2005-04-16 22:20:36 +00:00
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/*
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2007-09-20 08:31:38 +00:00
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* fs/sysfs/file.c - sysfs regular (text) file implementation
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*
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* Copyright (c) 2001-3 Patrick Mochel
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* Copyright (c) 2007 SUSE Linux Products GmbH
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* Copyright (c) 2007 Tejun Heo <teheo@suse.de>
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*
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* This file is released under the GPLv2.
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*
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* Please see Documentation/filesystems/sysfs.txt for more information.
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2005-04-16 22:20:36 +00:00
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*/
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#include <linux/module.h>
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#include <linux/kobject.h>
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2008-03-04 23:09:07 +00:00
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#include <linux/kallsyms.h>
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2008-03-14 02:41:52 +00:00
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#include <linux/slab.h>
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2008-06-16 11:46:47 +00:00
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#include <linux/fsnotify.h>
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2005-06-23 07:09:12 +00:00
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#include <linux/namei.h>
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2006-03-20 06:53:53 +00:00
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#include <linux/poll.h>
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2006-12-20 09:52:44 +00:00
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#include <linux/list.h>
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2007-07-26 11:03:54 +00:00
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#include <linux/mutex.h>
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2007-08-24 23:11:54 +00:00
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#include <linux/limits.h>
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2013-08-21 23:34:59 +00:00
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#include <linux/uaccess.h>
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2013-10-01 21:42:02 +00:00
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#include <linux/seq_file.h>
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2013-10-01 21:42:07 +00:00
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#include <linux/mm.h>
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2005-04-16 22:20:36 +00:00
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#include "sysfs.h"
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2007-09-20 07:05:12 +00:00
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/*
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2013-10-01 21:41:59 +00:00
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* There's one sysfs_open_file for each open file and one sysfs_open_dirent
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2013-10-01 21:41:58 +00:00
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* for each sysfs_dirent with one or more open files.
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2007-09-20 07:05:12 +00:00
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*
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2013-10-01 21:41:58 +00:00
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* sysfs_dirent->s_attr.open points to sysfs_open_dirent. s_attr.open is
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* protected by sysfs_open_dirent_lock.
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*
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2013-10-01 21:42:02 +00:00
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* filp->private_data points to seq_file whose ->private points to
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* sysfs_open_file. sysfs_open_files are chained at
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2013-10-01 21:41:59 +00:00
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* sysfs_open_dirent->files, which is protected by sysfs_open_file_mutex.
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2007-09-20 07:05:12 +00:00
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*/
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2007-11-21 22:55:19 +00:00
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static DEFINE_SPINLOCK(sysfs_open_dirent_lock);
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2013-10-01 21:41:58 +00:00
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static DEFINE_MUTEX(sysfs_open_file_mutex);
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2007-09-20 07:05:12 +00:00
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struct sysfs_open_dirent {
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atomic_t refcnt;
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2007-09-20 07:05:12 +00:00
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atomic_t event;
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wait_queue_head_t poll;
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2013-10-01 21:41:59 +00:00
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struct list_head files; /* goes through sysfs_open_file.list */
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2007-09-20 07:05:12 +00:00
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};
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2013-10-01 21:41:59 +00:00
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struct sysfs_open_file {
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2013-10-01 21:42:00 +00:00
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struct sysfs_dirent *sd;
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struct file *file;
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2007-07-26 11:03:54 +00:00
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struct mutex mutex;
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2007-06-13 18:45:16 +00:00
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int event;
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2007-09-20 07:05:12 +00:00
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struct list_head list;
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2013-10-01 21:42:07 +00:00
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bool mmapped;
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const struct vm_operations_struct *vm_ops;
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2007-06-13 18:45:16 +00:00
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};
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2005-04-16 22:20:36 +00:00
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2013-10-01 21:42:05 +00:00
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static bool sysfs_is_bin(struct sysfs_dirent *sd)
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{
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return sysfs_type(sd) == SYSFS_KOBJ_BIN_ATTR;
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}
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2013-10-01 21:42:02 +00:00
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static struct sysfs_open_file *sysfs_of(struct file *file)
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{
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return ((struct seq_file *)file->private_data)->private;
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}
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2013-10-01 21:41:57 +00:00
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/*
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* Determine ktype->sysfs_ops for the given sysfs_dirent. This function
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* must be called while holding an active reference.
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*/
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static const struct sysfs_ops *sysfs_file_ops(struct sysfs_dirent *sd)
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{
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struct kobject *kobj = sd->s_parent->s_dir.kobj;
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lockdep_assert_held(sd);
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return kobj->ktype ? kobj->ktype->sysfs_ops : NULL;
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}
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2013-10-01 21:42:02 +00:00
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/*
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* Reads on sysfs are handled through seq_file, which takes care of hairy
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* details like buffering and seeking. The following function pipes
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* sysfs_ops->show() result through seq_file.
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2005-04-16 22:20:36 +00:00
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*/
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2013-10-01 21:42:02 +00:00
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static int sysfs_seq_show(struct seq_file *sf, void *v)
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2005-04-16 22:20:36 +00:00
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{
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2013-10-01 21:42:02 +00:00
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struct sysfs_open_file *of = sf->private;
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struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
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2013-10-01 21:41:57 +00:00
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const struct sysfs_ops *ops;
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2013-10-01 21:42:02 +00:00
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char *buf;
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2005-04-16 22:20:36 +00:00
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ssize_t count;
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2013-10-01 21:42:02 +00:00
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/* acquire buffer and ensure that it's >= PAGE_SIZE */
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count = seq_get_buf(sf, &buf);
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if (count < PAGE_SIZE) {
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seq_commit(sf, -1);
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return 0;
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}
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2005-04-16 22:20:36 +00:00
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2013-10-01 21:42:02 +00:00
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/*
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* Need @of->sd for attr and ops, its parent for kobj. @of->mutex
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* nests outside active ref and is just to ensure that the ops
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* aren't called concurrently for the same open file.
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*/
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mutex_lock(&of->mutex);
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if (!sysfs_get_active(of->sd)) {
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mutex_unlock(&of->mutex);
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2007-06-13 18:45:16 +00:00
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return -ENODEV;
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2013-10-01 21:42:02 +00:00
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}
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2007-06-13 18:45:16 +00:00
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2013-10-01 21:42:02 +00:00
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of->event = atomic_read(&of->sd->s_attr.open->event);
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2013-10-01 21:41:57 +00:00
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2013-10-01 21:42:02 +00:00
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/*
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* Lookup @ops and invoke show(). Control may reach here via seq
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* file lseek even if @ops->show() isn't implemented.
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*/
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ops = sysfs_file_ops(of->sd);
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if (ops->show)
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count = ops->show(kobj, of->sd->s_attr.attr, buf);
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else
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count = 0;
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2007-06-13 18:45:16 +00:00
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2013-10-01 21:42:02 +00:00
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sysfs_put_active(of->sd);
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mutex_unlock(&of->mutex);
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if (count < 0)
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return count;
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2007-06-13 18:45:16 +00:00
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2007-11-21 22:55:19 +00:00
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/*
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* The code works fine with PAGE_SIZE return but it's likely to
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* indicate truncated result or overflow in normal use cases.
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*/
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2008-03-04 23:09:07 +00:00
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if (count >= (ssize_t)PAGE_SIZE) {
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print_symbol("fill_read_buffer: %s returned bad count\n",
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(unsigned long)ops->show);
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/* Try to struggle along */
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count = PAGE_SIZE - 1;
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}
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2013-10-01 21:42:02 +00:00
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seq_commit(sf, count);
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return 0;
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2005-04-16 22:20:36 +00:00
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}
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2013-10-01 21:42:06 +00:00
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/*
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* Read method for bin files. As reading a bin file can have side-effects,
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* the exact offset and bytes specified in read(2) call should be passed to
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* the read callback making it difficult to use seq_file. Implement
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* simplistic custom buffering for bin files.
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*/
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static ssize_t sysfs_bin_read(struct file *file, char __user *userbuf,
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size_t bytes, loff_t *off)
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{
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struct sysfs_open_file *of = sysfs_of(file);
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struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
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struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
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int size = file_inode(file)->i_size;
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int count = min_t(size_t, bytes, PAGE_SIZE);
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loff_t offs = *off;
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char *buf;
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if (!bytes)
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return 0;
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if (size) {
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if (offs > size)
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return 0;
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if (offs + count > size)
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count = size - offs;
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}
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buf = kmalloc(count, GFP_KERNEL);
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if (!buf)
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return -ENOMEM;
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/* need of->sd for battr, its parent for kobj */
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mutex_lock(&of->mutex);
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if (!sysfs_get_active(of->sd)) {
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count = -ENODEV;
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mutex_unlock(&of->mutex);
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goto out_free;
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}
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if (battr->read)
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count = battr->read(file, kobj, battr, buf, offs, count);
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else
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count = -EIO;
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sysfs_put_active(of->sd);
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mutex_unlock(&of->mutex);
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if (count < 0)
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goto out_free;
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if (copy_to_user(userbuf, buf, count)) {
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count = -EFAULT;
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goto out_free;
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}
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pr_debug("offs = %lld, *off = %lld, count = %d\n", offs, *off, count);
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*off = offs + count;
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out_free:
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kfree(buf);
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return count;
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}
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2005-04-16 22:20:36 +00:00
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/**
|
2013-10-01 21:42:01 +00:00
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* flush_write_buffer - push buffer to kobject
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* @of: open file
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* @buf: data buffer for file
|
2013-10-01 21:42:05 +00:00
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* @off: file offset to write to
|
2013-10-01 21:42:01 +00:00
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* @count: number of bytes
|
2005-04-16 22:20:36 +00:00
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*
|
2013-10-01 21:42:01 +00:00
|
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* Get the correct pointers for the kobject and the attribute we're dealing
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* with, then call the store() method for it with @buf.
|
2005-04-16 22:20:36 +00:00
|
|
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*/
|
2013-10-01 21:42:05 +00:00
|
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static int flush_write_buffer(struct sysfs_open_file *of, char *buf, loff_t off,
|
2013-10-01 21:42:01 +00:00
|
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size_t count)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2013-10-01 21:42:00 +00:00
|
|
|
struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
|
2013-10-01 21:42:01 +00:00
|
|
|
int rc = 0;
|
2007-06-13 18:45:16 +00:00
|
|
|
|
2013-10-01 21:42:01 +00:00
|
|
|
/*
|
|
|
|
* Need @of->sd for attr and ops, its parent for kobj. @of->mutex
|
|
|
|
* nests outside active ref and is just to ensure that the ops
|
|
|
|
* aren't called concurrently for the same open file.
|
|
|
|
*/
|
|
|
|
mutex_lock(&of->mutex);
|
|
|
|
if (!sysfs_get_active(of->sd)) {
|
|
|
|
mutex_unlock(&of->mutex);
|
2007-06-13 18:45:16 +00:00
|
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|
return -ENODEV;
|
2013-10-01 21:42:01 +00:00
|
|
|
}
|
2007-06-13 18:45:16 +00:00
|
|
|
|
2013-10-01 21:42:05 +00:00
|
|
|
if (sysfs_is_bin(of->sd)) {
|
|
|
|
struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
|
|
|
|
|
|
|
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rc = -EIO;
|
|
|
|
if (battr->write)
|
|
|
|
rc = battr->write(of->file, kobj, battr, buf, off,
|
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|
|
count);
|
|
|
|
} else {
|
|
|
|
const struct sysfs_ops *ops = sysfs_file_ops(of->sd);
|
|
|
|
|
|
|
|
rc = ops->store(kobj, of->sd->s_attr.attr, buf, count);
|
|
|
|
}
|
2007-06-13 18:45:16 +00:00
|
|
|
|
2013-10-01 21:42:00 +00:00
|
|
|
sysfs_put_active(of->sd);
|
2013-10-01 21:42:01 +00:00
|
|
|
mutex_unlock(&of->mutex);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-06-13 18:45:16 +00:00
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
2013-10-01 21:42:01 +00:00
|
|
|
* sysfs_write_file - write an attribute
|
|
|
|
* @file: file pointer
|
|
|
|
* @user_buf: data to write
|
|
|
|
* @count: number of bytes
|
|
|
|
* @ppos: starting offset
|
|
|
|
*
|
|
|
|
* Copy data in from userland and pass it to the matching
|
|
|
|
* sysfs_ops->store() by invoking flush_write_buffer().
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
2013-10-01 21:42:01 +00:00
|
|
|
* There is no easy way for us to know if userspace is only doing a partial
|
|
|
|
* write, so we don't support them. We expect the entire buffer to come on
|
|
|
|
* the first write. Hint: if you're writing a value, first read the file,
|
|
|
|
* modify only the the value you're changing, then write entire buffer
|
|
|
|
* back.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2013-10-01 21:42:01 +00:00
|
|
|
static ssize_t sysfs_write_file(struct file *file, const char __user *user_buf,
|
2013-08-21 23:33:34 +00:00
|
|
|
size_t count, loff_t *ppos)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2013-10-01 21:42:02 +00:00
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
2013-10-01 21:42:05 +00:00
|
|
|
ssize_t len = min_t(size_t, count, PAGE_SIZE);
|
2013-10-01 21:42:01 +00:00
|
|
|
char *buf;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:42:05 +00:00
|
|
|
if (sysfs_is_bin(of->sd)) {
|
|
|
|
loff_t size = file_inode(file)->i_size;
|
|
|
|
|
|
|
|
if (size <= *ppos)
|
|
|
|
return 0;
|
|
|
|
len = min_t(ssize_t, len, size - *ppos);
|
|
|
|
}
|
|
|
|
|
2013-10-01 21:42:01 +00:00
|
|
|
if (!len)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
buf = kmalloc(len + 1, GFP_KERNEL);
|
|
|
|
if (!buf)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
if (copy_from_user(buf, user_buf, len)) {
|
|
|
|
len = -EFAULT;
|
|
|
|
goto out_free;
|
|
|
|
}
|
|
|
|
buf[len] = '\0'; /* guarantee string termination */
|
|
|
|
|
2013-10-01 21:42:05 +00:00
|
|
|
len = flush_write_buffer(of, buf, *ppos, len);
|
2005-04-16 22:20:36 +00:00
|
|
|
if (len > 0)
|
|
|
|
*ppos += len;
|
2013-10-01 21:42:01 +00:00
|
|
|
out_free:
|
|
|
|
kfree(buf);
|
2005-04-16 22:20:36 +00:00
|
|
|
return len;
|
|
|
|
}
|
|
|
|
|
2013-10-01 21:42:07 +00:00
|
|
|
static void sysfs_bin_vma_open(struct vm_area_struct *vma)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (of->vm_ops->open)
|
|
|
|
of->vm_ops->open(vma);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
}
|
|
|
|
|
|
|
|
static int sysfs_bin_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
|
|
|
|
ret = VM_FAULT_SIGBUS;
|
|
|
|
if (of->vm_ops->fault)
|
|
|
|
ret = of->vm_ops->fault(vma, vmf);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int sysfs_bin_page_mkwrite(struct vm_area_struct *vma,
|
|
|
|
struct vm_fault *vmf)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return VM_FAULT_SIGBUS;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
if (of->vm_ops->page_mkwrite)
|
|
|
|
ret = of->vm_ops->page_mkwrite(vma, vmf);
|
|
|
|
else
|
|
|
|
file_update_time(file);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int sysfs_bin_access(struct vm_area_struct *vma, unsigned long addr,
|
|
|
|
void *buf, int len, int write)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
if (of->vm_ops->access)
|
|
|
|
ret = of->vm_ops->access(vma, addr, buf, len, write);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef CONFIG_NUMA
|
|
|
|
static int sysfs_bin_set_policy(struct vm_area_struct *vma,
|
|
|
|
struct mempolicy *new)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return -EINVAL;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
if (of->vm_ops->set_policy)
|
|
|
|
ret = of->vm_ops->set_policy(vma, new);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
|
|
|
|
static struct mempolicy *sysfs_bin_get_policy(struct vm_area_struct *vma,
|
|
|
|
unsigned long addr)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
struct mempolicy *pol;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return vma->vm_policy;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return vma->vm_policy;
|
|
|
|
|
|
|
|
pol = vma->vm_policy;
|
|
|
|
if (of->vm_ops->get_policy)
|
|
|
|
pol = of->vm_ops->get_policy(vma, addr);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return pol;
|
|
|
|
}
|
|
|
|
|
|
|
|
static int sysfs_bin_migrate(struct vm_area_struct *vma, const nodemask_t *from,
|
|
|
|
const nodemask_t *to, unsigned long flags)
|
|
|
|
{
|
|
|
|
struct file *file = vma->vm_file;
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
if (!of->vm_ops)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
ret = 0;
|
|
|
|
if (of->vm_ops->migrate)
|
|
|
|
ret = of->vm_ops->migrate(vma, from, to, flags);
|
|
|
|
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
return ret;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
static const struct vm_operations_struct sysfs_bin_vm_ops = {
|
|
|
|
.open = sysfs_bin_vma_open,
|
|
|
|
.fault = sysfs_bin_fault,
|
|
|
|
.page_mkwrite = sysfs_bin_page_mkwrite,
|
|
|
|
.access = sysfs_bin_access,
|
|
|
|
#ifdef CONFIG_NUMA
|
|
|
|
.set_policy = sysfs_bin_set_policy,
|
|
|
|
.get_policy = sysfs_bin_get_policy,
|
|
|
|
.migrate = sysfs_bin_migrate,
|
|
|
|
#endif
|
|
|
|
};
|
|
|
|
|
|
|
|
static int sysfs_bin_mmap(struct file *file, struct vm_area_struct *vma)
|
|
|
|
{
|
|
|
|
struct sysfs_open_file *of = sysfs_of(file);
|
|
|
|
struct bin_attribute *battr = of->sd->s_bin_attr.bin_attr;
|
|
|
|
struct kobject *kobj = of->sd->s_parent->s_dir.kobj;
|
|
|
|
int rc;
|
|
|
|
|
|
|
|
mutex_lock(&of->mutex);
|
|
|
|
|
|
|
|
/* need of->sd for battr, its parent for kobj */
|
|
|
|
rc = -ENODEV;
|
|
|
|
if (!sysfs_get_active(of->sd))
|
|
|
|
goto out_unlock;
|
|
|
|
|
|
|
|
rc = -EINVAL;
|
|
|
|
if (!battr->mmap)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
rc = battr->mmap(file, kobj, battr, vma);
|
|
|
|
if (rc)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* PowerPC's pci_mmap of legacy_mem uses shmem_zero_setup()
|
|
|
|
* to satisfy versions of X which crash if the mmap fails: that
|
|
|
|
* substitutes a new vm_file, and we don't then want bin_vm_ops.
|
|
|
|
*/
|
|
|
|
if (vma->vm_file != file)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
rc = -EINVAL;
|
|
|
|
if (of->mmapped && of->vm_ops != vma->vm_ops)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
/*
|
|
|
|
* It is not possible to successfully wrap close.
|
|
|
|
* So error if someone is trying to use close.
|
|
|
|
*/
|
|
|
|
rc = -EINVAL;
|
|
|
|
if (vma->vm_ops && vma->vm_ops->close)
|
|
|
|
goto out_put;
|
|
|
|
|
|
|
|
rc = 0;
|
|
|
|
of->mmapped = 1;
|
|
|
|
of->vm_ops = vma->vm_ops;
|
|
|
|
vma->vm_ops = &sysfs_bin_vm_ops;
|
|
|
|
out_put:
|
|
|
|
sysfs_put_active(of->sd);
|
|
|
|
out_unlock:
|
|
|
|
mutex_unlock(&of->mutex);
|
|
|
|
|
|
|
|
return rc;
|
|
|
|
}
|
|
|
|
|
2007-09-20 07:05:12 +00:00
|
|
|
/**
|
|
|
|
* sysfs_get_open_dirent - get or create sysfs_open_dirent
|
|
|
|
* @sd: target sysfs_dirent
|
2013-10-01 21:41:59 +00:00
|
|
|
* @of: sysfs_open_file for this instance of open
|
2007-09-20 07:05:12 +00:00
|
|
|
*
|
|
|
|
* If @sd->s_attr.open exists, increment its reference count;
|
2013-10-01 21:41:59 +00:00
|
|
|
* otherwise, create one. @of is chained to the files list.
|
2007-09-20 07:05:12 +00:00
|
|
|
*
|
|
|
|
* LOCKING:
|
|
|
|
* Kernel thread context (may sleep).
|
|
|
|
*
|
|
|
|
* RETURNS:
|
|
|
|
* 0 on success, -errno on failure.
|
|
|
|
*/
|
|
|
|
static int sysfs_get_open_dirent(struct sysfs_dirent *sd,
|
2013-10-01 21:41:59 +00:00
|
|
|
struct sysfs_open_file *of)
|
2007-09-20 07:05:12 +00:00
|
|
|
{
|
|
|
|
struct sysfs_open_dirent *od, *new_od = NULL;
|
|
|
|
|
|
|
|
retry:
|
2013-10-01 21:41:58 +00:00
|
|
|
mutex_lock(&sysfs_open_file_mutex);
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_lock_irq(&sysfs_open_dirent_lock);
|
2007-09-20 07:05:12 +00:00
|
|
|
|
|
|
|
if (!sd->s_attr.open && new_od) {
|
|
|
|
sd->s_attr.open = new_od;
|
|
|
|
new_od = NULL;
|
|
|
|
}
|
|
|
|
|
|
|
|
od = sd->s_attr.open;
|
|
|
|
if (od) {
|
|
|
|
atomic_inc(&od->refcnt);
|
2013-10-01 21:41:59 +00:00
|
|
|
list_add_tail(&of->list, &od->files);
|
2007-09-20 07:05:12 +00:00
|
|
|
}
|
|
|
|
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_unlock_irq(&sysfs_open_dirent_lock);
|
2013-10-01 21:41:58 +00:00
|
|
|
mutex_unlock(&sysfs_open_file_mutex);
|
2007-09-20 07:05:12 +00:00
|
|
|
|
|
|
|
if (od) {
|
|
|
|
kfree(new_od);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* not there, initialize a new one and retry */
|
|
|
|
new_od = kmalloc(sizeof(*new_od), GFP_KERNEL);
|
|
|
|
if (!new_od)
|
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
atomic_set(&new_od->refcnt, 0);
|
2007-09-20 07:05:12 +00:00
|
|
|
atomic_set(&new_od->event, 1);
|
|
|
|
init_waitqueue_head(&new_od->poll);
|
2013-10-01 21:41:59 +00:00
|
|
|
INIT_LIST_HEAD(&new_od->files);
|
2007-09-20 07:05:12 +00:00
|
|
|
goto retry;
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* sysfs_put_open_dirent - put sysfs_open_dirent
|
|
|
|
* @sd: target sysfs_dirent
|
2013-10-01 21:41:59 +00:00
|
|
|
* @of: associated sysfs_open_file
|
2007-09-20 07:05:12 +00:00
|
|
|
*
|
2013-10-01 21:41:59 +00:00
|
|
|
* Put @sd->s_attr.open and unlink @of from the files list. If
|
|
|
|
* reference count reaches zero, disassociate and free it.
|
2007-09-20 07:05:12 +00:00
|
|
|
*
|
|
|
|
* LOCKING:
|
|
|
|
* None.
|
|
|
|
*/
|
|
|
|
static void sysfs_put_open_dirent(struct sysfs_dirent *sd,
|
2013-10-01 21:41:59 +00:00
|
|
|
struct sysfs_open_file *of)
|
2007-09-20 07:05:12 +00:00
|
|
|
{
|
|
|
|
struct sysfs_open_dirent *od = sd->s_attr.open;
|
2009-09-15 23:05:51 +00:00
|
|
|
unsigned long flags;
|
2007-09-20 07:05:12 +00:00
|
|
|
|
2013-10-01 21:41:58 +00:00
|
|
|
mutex_lock(&sysfs_open_file_mutex);
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
|
2007-09-20 07:05:12 +00:00
|
|
|
|
2013-10-01 21:42:07 +00:00
|
|
|
if (of)
|
|
|
|
list_del(&of->list);
|
|
|
|
|
2007-09-20 07:05:12 +00:00
|
|
|
if (atomic_dec_and_test(&od->refcnt))
|
|
|
|
sd->s_attr.open = NULL;
|
|
|
|
else
|
|
|
|
od = NULL;
|
|
|
|
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
|
2013-10-01 21:41:58 +00:00
|
|
|
mutex_unlock(&sysfs_open_file_mutex);
|
2007-09-20 07:05:12 +00:00
|
|
|
|
|
|
|
kfree(od);
|
|
|
|
}
|
|
|
|
|
2006-12-20 09:52:44 +00:00
|
|
|
static int sysfs_open_file(struct inode *inode, struct file *file)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-06-13 18:45:15 +00:00
|
|
|
struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
|
2007-09-20 07:05:11 +00:00
|
|
|
struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
|
2013-10-01 21:41:59 +00:00
|
|
|
struct sysfs_open_file *of;
|
2013-10-01 21:42:08 +00:00
|
|
|
bool has_read, has_write;
|
2007-11-02 12:47:53 +00:00
|
|
|
int error = -EACCES;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-06-13 18:45:16 +00:00
|
|
|
/* need attr_sd for attr and ops, its parent for kobj */
|
2010-02-11 23:18:38 +00:00
|
|
|
if (!sysfs_get_active(attr_sd))
|
2007-06-13 18:45:16 +00:00
|
|
|
return -ENODEV;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:42:08 +00:00
|
|
|
if (sysfs_is_bin(attr_sd)) {
|
|
|
|
struct bin_attribute *battr = attr_sd->s_bin_attr.bin_attr;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:42:08 +00:00
|
|
|
has_read = battr->read || battr->mmap;
|
|
|
|
has_write = battr->write || battr->mmap;
|
|
|
|
} else {
|
|
|
|
const struct sysfs_ops *ops = sysfs_file_ops(attr_sd);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:42:08 +00:00
|
|
|
/* every kobject with an attribute needs a ktype assigned */
|
|
|
|
if (WARN(!ops, KERN_ERR
|
|
|
|
"missing sysfs attribute operations for kobject: %s\n",
|
|
|
|
kobject_name(kobj)))
|
2007-06-13 18:45:17 +00:00
|
|
|
goto err_out;
|
2013-10-01 21:42:08 +00:00
|
|
|
|
|
|
|
has_read = ops->show;
|
|
|
|
has_write = ops->store;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
2013-10-01 21:42:08 +00:00
|
|
|
/* check perms and supported operations */
|
|
|
|
if ((file->f_mode & FMODE_WRITE) &&
|
|
|
|
(!(inode->i_mode & S_IWUGO) || !has_write))
|
|
|
|
goto err_out;
|
|
|
|
|
|
|
|
if ((file->f_mode & FMODE_READ) &&
|
|
|
|
(!(inode->i_mode & S_IRUGO) || !has_read))
|
|
|
|
goto err_out;
|
|
|
|
|
2013-10-01 21:42:02 +00:00
|
|
|
/* allocate a sysfs_open_file for the file */
|
2007-06-13 18:45:16 +00:00
|
|
|
error = -ENOMEM;
|
2013-10-01 21:41:59 +00:00
|
|
|
of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL);
|
|
|
|
if (!of)
|
2007-06-13 18:45:17 +00:00
|
|
|
goto err_out;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:41:59 +00:00
|
|
|
mutex_init(&of->mutex);
|
2013-10-01 21:42:00 +00:00
|
|
|
of->sd = attr_sd;
|
|
|
|
of->file = file;
|
2013-10-01 21:42:02 +00:00
|
|
|
|
|
|
|
/*
|
2013-10-01 21:42:08 +00:00
|
|
|
* Always instantiate seq_file even if read access doesn't use
|
|
|
|
* seq_file or is not requested. This unifies private data access
|
|
|
|
* and readable regular files are the vast majority anyway.
|
2013-10-01 21:42:02 +00:00
|
|
|
*/
|
2013-10-01 21:42:08 +00:00
|
|
|
if (sysfs_is_bin(attr_sd))
|
|
|
|
error = single_open(file, NULL, of);
|
|
|
|
else
|
|
|
|
error = single_open(file, sysfs_seq_show, of);
|
2013-10-01 21:42:02 +00:00
|
|
|
if (error)
|
|
|
|
goto err_free;
|
|
|
|
|
|
|
|
/* seq_file clears PWRITE unconditionally, restore it if WRITE */
|
|
|
|
if (file->f_mode & FMODE_WRITE)
|
|
|
|
file->f_mode |= FMODE_PWRITE;
|
2007-06-13 18:45:16 +00:00
|
|
|
|
2007-09-20 07:05:12 +00:00
|
|
|
/* make sure we have open dirent struct */
|
2013-10-01 21:41:59 +00:00
|
|
|
error = sysfs_get_open_dirent(attr_sd, of);
|
2007-09-20 07:05:12 +00:00
|
|
|
if (error)
|
2013-10-01 21:42:02 +00:00
|
|
|
goto err_close;
|
2007-09-20 07:05:12 +00:00
|
|
|
|
2007-09-20 07:05:10 +00:00
|
|
|
/* open succeeded, put active references */
|
2010-02-11 23:18:38 +00:00
|
|
|
sysfs_put_active(attr_sd);
|
2007-06-13 18:45:16 +00:00
|
|
|
return 0;
|
|
|
|
|
2013-10-01 21:42:02 +00:00
|
|
|
err_close:
|
|
|
|
single_release(inode, file);
|
|
|
|
err_free:
|
2013-10-01 21:41:59 +00:00
|
|
|
kfree(of);
|
2013-10-01 21:42:02 +00:00
|
|
|
err_out:
|
2010-02-11 23:18:38 +00:00
|
|
|
sysfs_put_active(attr_sd);
|
2005-04-16 22:20:36 +00:00
|
|
|
return error;
|
|
|
|
}
|
|
|
|
|
2007-09-20 07:05:12 +00:00
|
|
|
static int sysfs_release(struct inode *inode, struct file *filp)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-09-20 07:05:12 +00:00
|
|
|
struct sysfs_dirent *sd = filp->f_path.dentry->d_fsdata;
|
2013-10-01 21:42:02 +00:00
|
|
|
struct sysfs_open_file *of = sysfs_of(filp);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-10-01 21:41:59 +00:00
|
|
|
sysfs_put_open_dirent(sd, of);
|
2013-10-01 21:42:02 +00:00
|
|
|
single_release(inode, filp);
|
2013-10-01 21:41:59 +00:00
|
|
|
kfree(of);
|
2007-09-20 07:05:10 +00:00
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
2013-10-01 21:42:07 +00:00
|
|
|
void sysfs_unmap_bin_file(struct sysfs_dirent *sd)
|
|
|
|
{
|
|
|
|
struct sysfs_open_dirent *od;
|
|
|
|
struct sysfs_open_file *of;
|
|
|
|
|
|
|
|
if (!sysfs_is_bin(sd))
|
|
|
|
return;
|
|
|
|
|
|
|
|
spin_lock_irq(&sysfs_open_dirent_lock);
|
|
|
|
od = sd->s_attr.open;
|
|
|
|
if (od)
|
|
|
|
atomic_inc(&od->refcnt);
|
|
|
|
spin_unlock_irq(&sysfs_open_dirent_lock);
|
|
|
|
if (!od)
|
|
|
|
return;
|
|
|
|
|
|
|
|
mutex_lock(&sysfs_open_file_mutex);
|
|
|
|
list_for_each_entry(of, &od->files, list) {
|
|
|
|
struct inode *inode = file_inode(of->file);
|
|
|
|
unmap_mapping_range(inode->i_mapping, 0, 0, 1);
|
|
|
|
}
|
|
|
|
mutex_unlock(&sysfs_open_file_mutex);
|
|
|
|
|
|
|
|
sysfs_put_open_dirent(sd, NULL);
|
|
|
|
}
|
|
|
|
|
2006-03-20 06:53:53 +00:00
|
|
|
/* Sysfs attribute files are pollable. The idea is that you read
|
|
|
|
* the content and then you use 'poll' or 'select' to wait for
|
|
|
|
* the content to change. When the content changes (assuming the
|
|
|
|
* manager for the kobject supports notification), poll will
|
|
|
|
* return POLLERR|POLLPRI, and select will return the fd whether
|
|
|
|
* it is waiting for read, write, or exceptions.
|
|
|
|
* Once poll/select indicates that the value has changed, you
|
2008-04-07 22:35:01 +00:00
|
|
|
* need to close and re-open the file, or seek to 0 and read again.
|
2006-03-20 06:53:53 +00:00
|
|
|
* Reminder: this only works for attributes which actively support
|
|
|
|
* it, and it is not possible to test an attribute from userspace
|
2007-08-10 20:51:07 +00:00
|
|
|
* to see if it supports poll (Neither 'poll' nor 'select' return
|
2006-03-20 06:53:53 +00:00
|
|
|
* an appropriate error code). When in doubt, set a suitable timeout value.
|
|
|
|
*/
|
|
|
|
static unsigned int sysfs_poll(struct file *filp, poll_table *wait)
|
|
|
|
{
|
2013-10-01 21:42:02 +00:00
|
|
|
struct sysfs_open_file *of = sysfs_of(filp);
|
2007-06-13 18:45:16 +00:00
|
|
|
struct sysfs_dirent *attr_sd = filp->f_path.dentry->d_fsdata;
|
2007-09-20 07:05:12 +00:00
|
|
|
struct sysfs_open_dirent *od = attr_sd->s_attr.open;
|
2007-06-13 18:45:16 +00:00
|
|
|
|
|
|
|
/* need parent for the kobj, grab both */
|
2010-02-11 23:18:38 +00:00
|
|
|
if (!sysfs_get_active(attr_sd))
|
2007-06-13 18:45:16 +00:00
|
|
|
goto trigger;
|
2006-03-20 06:53:53 +00:00
|
|
|
|
2007-09-20 07:05:12 +00:00
|
|
|
poll_wait(filp, &od->poll, wait);
|
2006-03-20 06:53:53 +00:00
|
|
|
|
2010-02-11 23:18:38 +00:00
|
|
|
sysfs_put_active(attr_sd);
|
2007-06-13 18:45:16 +00:00
|
|
|
|
2013-10-01 21:41:59 +00:00
|
|
|
if (of->event != atomic_read(&od->event))
|
2007-06-13 18:45:16 +00:00
|
|
|
goto trigger;
|
2006-03-20 06:53:53 +00:00
|
|
|
|
sysfs: sysfs poll keep the poll rule of regular file.
Currently, following test programs don't finished.
% ruby -e '
Thread.new { sleep }
File.read("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies")
'
strace expose the reason.
...
open("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", O_RDONLY|O_LARGEFILE) = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbf9fa6b8) = -1 ENOTTY (Inappropriate ioctl for device)
fstat64(3, {st_mode=S_IFREG|0444, st_size=4096, ...}) = 0
_llseek(3, 0, [0], SEEK_CUR) = 0
select(4, [3], NULL, NULL, NULL) = 1 (in [3])
read(3, "1400000 1300000 1200000 1100000 1"..., 4096) = 62
select(4, [3], NULL, NULL, NULL
Because Ruby (the scripting language) VM assume select system-call
against regular file don't block. it because SUSv3 says "Regular files
shall always poll TRUE for reading and writing". see
http://www.opengroup.org/onlinepubs/009695399/functions/poll.html it
seems valid assumption.
But sysfs_poll() don't keep this rule although sysfs file can read and
write always.
This patch restore proper poll behavior to sysfs.
/sys/block/md*/md/sync_action polling application and another sysfs
updating sensitive application still can use POLLERR and POLLPRI.
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-09 04:53:22 +00:00
|
|
|
return DEFAULT_POLLMASK;
|
2007-06-13 18:45:16 +00:00
|
|
|
|
|
|
|
trigger:
|
sysfs: sysfs poll keep the poll rule of regular file.
Currently, following test programs don't finished.
% ruby -e '
Thread.new { sleep }
File.read("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies")
'
strace expose the reason.
...
open("/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies", O_RDONLY|O_LARGEFILE) = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbf9fa6b8) = -1 ENOTTY (Inappropriate ioctl for device)
fstat64(3, {st_mode=S_IFREG|0444, st_size=4096, ...}) = 0
_llseek(3, 0, [0], SEEK_CUR) = 0
select(4, [3], NULL, NULL, NULL) = 1 (in [3])
read(3, "1400000 1300000 1200000 1100000 1"..., 4096) = 62
select(4, [3], NULL, NULL, NULL
Because Ruby (the scripting language) VM assume select system-call
against regular file don't block. it because SUSv3 says "Regular files
shall always poll TRUE for reading and writing". see
http://www.opengroup.org/onlinepubs/009695399/functions/poll.html it
seems valid assumption.
But sysfs_poll() don't keep this rule although sysfs file can read and
write always.
This patch restore proper poll behavior to sysfs.
/sys/block/md*/md/sync_action polling application and another sysfs
updating sensitive application still can use POLLERR and POLLPRI.
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-04-09 04:53:22 +00:00
|
|
|
return DEFAULT_POLLMASK|POLLERR|POLLPRI;
|
2006-03-20 06:53:53 +00:00
|
|
|
}
|
|
|
|
|
2008-07-15 22:58:04 +00:00
|
|
|
void sysfs_notify_dirent(struct sysfs_dirent *sd)
|
|
|
|
{
|
|
|
|
struct sysfs_open_dirent *od;
|
2009-09-15 23:05:51 +00:00
|
|
|
unsigned long flags;
|
2008-07-15 22:58:04 +00:00
|
|
|
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_lock_irqsave(&sysfs_open_dirent_lock, flags);
|
2008-07-15 22:58:04 +00:00
|
|
|
|
2013-06-07 14:45:13 +00:00
|
|
|
if (!WARN_ON(sysfs_type(sd) != SYSFS_KOBJ_ATTR)) {
|
|
|
|
od = sd->s_attr.open;
|
|
|
|
if (od) {
|
|
|
|
atomic_inc(&od->event);
|
|
|
|
wake_up_interruptible(&od->poll);
|
|
|
|
}
|
2008-07-15 22:58:04 +00:00
|
|
|
}
|
|
|
|
|
2009-09-15 23:05:51 +00:00
|
|
|
spin_unlock_irqrestore(&sysfs_open_dirent_lock, flags);
|
2008-07-15 22:58:04 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_notify_dirent);
|
|
|
|
|
2008-09-25 23:45:13 +00:00
|
|
|
void sysfs_notify(struct kobject *k, const char *dir, const char *attr)
|
2006-03-20 06:53:53 +00:00
|
|
|
{
|
2007-06-13 19:27:25 +00:00
|
|
|
struct sysfs_dirent *sd = k->sd;
|
2006-03-20 06:53:53 +00:00
|
|
|
|
2007-06-13 19:27:25 +00:00
|
|
|
mutex_lock(&sysfs_mutex);
|
|
|
|
|
|
|
|
if (sd && dir)
|
2013-09-12 02:29:09 +00:00
|
|
|
sd = sysfs_find_dirent(sd, dir, NULL);
|
2007-06-13 19:27:25 +00:00
|
|
|
if (sd && attr)
|
2013-09-12 02:29:09 +00:00
|
|
|
sd = sysfs_find_dirent(sd, attr, NULL);
|
2008-07-15 22:58:04 +00:00
|
|
|
if (sd)
|
|
|
|
sysfs_notify_dirent(sd);
|
2007-06-13 19:27:25 +00:00
|
|
|
|
|
|
|
mutex_unlock(&sysfs_mutex);
|
2006-03-20 06:53:53 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_notify);
|
|
|
|
|
2006-03-28 09:56:42 +00:00
|
|
|
const struct file_operations sysfs_file_operations = {
|
2013-10-01 21:42:02 +00:00
|
|
|
.read = seq_read,
|
2005-04-16 22:20:36 +00:00
|
|
|
.write = sysfs_write_file,
|
2013-10-01 21:42:02 +00:00
|
|
|
.llseek = seq_lseek,
|
2005-04-16 22:20:36 +00:00
|
|
|
.open = sysfs_open_file,
|
|
|
|
.release = sysfs_release,
|
2006-03-20 06:53:53 +00:00
|
|
|
.poll = sysfs_poll,
|
2005-04-16 22:20:36 +00:00
|
|
|
};
|
|
|
|
|
2013-10-01 21:42:05 +00:00
|
|
|
const struct file_operations sysfs_bin_operations = {
|
2013-10-01 21:42:06 +00:00
|
|
|
.read = sysfs_bin_read,
|
2013-10-01 21:42:05 +00:00
|
|
|
.write = sysfs_write_file,
|
|
|
|
.llseek = generic_file_llseek,
|
2013-10-01 21:42:07 +00:00
|
|
|
.mmap = sysfs_bin_mmap,
|
2013-10-01 21:42:08 +00:00
|
|
|
.open = sysfs_open_file,
|
|
|
|
.release = sysfs_release,
|
|
|
|
.poll = sysfs_poll,
|
2013-10-01 21:42:05 +00:00
|
|
|
};
|
|
|
|
|
2013-09-12 02:29:04 +00:00
|
|
|
int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,
|
|
|
|
const struct attribute *attr, int type,
|
|
|
|
umode_t amode, const void *ns)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2008-03-21 01:47:52 +00:00
|
|
|
umode_t mode = (amode & S_IALLUGO) | S_IFREG;
|
2007-06-13 19:27:24 +00:00
|
|
|
struct sysfs_addrm_cxt acxt;
|
2007-06-13 18:45:14 +00:00
|
|
|
struct sysfs_dirent *sd;
|
2007-08-02 12:38:03 +00:00
|
|
|
int rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-06-13 19:27:23 +00:00
|
|
|
sd = sysfs_new_dirent(attr->name, mode, type);
|
|
|
|
if (!sd)
|
|
|
|
return -ENOMEM;
|
2011-10-12 21:53:38 +00:00
|
|
|
|
|
|
|
sd->s_ns = ns;
|
2007-09-20 07:05:11 +00:00
|
|
|
sd->s_attr.attr = (void *)attr;
|
2010-02-11 23:20:00 +00:00
|
|
|
sysfs_dirent_init_lockdep(sd);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-09-18 21:15:35 +00:00
|
|
|
sysfs_addrm_start(&acxt);
|
|
|
|
rc = sysfs_add_one(&acxt, sd, dir_sd);
|
2007-08-02 12:38:03 +00:00
|
|
|
sysfs_addrm_finish(&acxt);
|
2007-06-13 18:45:14 +00:00
|
|
|
|
2007-08-02 12:38:03 +00:00
|
|
|
if (rc)
|
2007-07-18 07:38:11 +00:00
|
|
|
sysfs_put(sd);
|
2007-06-13 19:27:23 +00:00
|
|
|
|
2007-08-02 12:38:03 +00:00
|
|
|
return rc;
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
|
|
|
|
|
|
|
|
2008-03-21 01:47:52 +00:00
|
|
|
int sysfs_add_file(struct sysfs_dirent *dir_sd, const struct attribute *attr,
|
|
|
|
int type)
|
|
|
|
{
|
2013-09-12 02:29:04 +00:00
|
|
|
return sysfs_add_file_mode_ns(dir_sd, attr, type, attr->mode, NULL);
|
2008-03-21 01:47:52 +00:00
|
|
|
}
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/**
|
2013-09-12 02:29:04 +00:00
|
|
|
* sysfs_create_file_ns - create an attribute file for an object with custom ns
|
|
|
|
* @kobj: object we're creating for
|
|
|
|
* @attr: attribute descriptor
|
|
|
|
* @ns: namespace the new file should belong to
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2013-09-12 02:29:04 +00:00
|
|
|
int sysfs_create_file_ns(struct kobject *kobj, const struct attribute *attr,
|
|
|
|
const void *ns)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2007-06-13 19:27:22 +00:00
|
|
|
BUG_ON(!kobj || !kobj->sd || !attr);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-09-12 02:29:04 +00:00
|
|
|
return sysfs_add_file_mode_ns(kobj->sd, attr, SYSFS_KOBJ_ATTR,
|
|
|
|
attr->mode, ns);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
|
|
|
}
|
2013-09-12 02:29:04 +00:00
|
|
|
EXPORT_SYMBOL_GPL(sysfs_create_file_ns);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2010-01-05 11:48:01 +00:00
|
|
|
int sysfs_create_files(struct kobject *kobj, const struct attribute **ptr)
|
|
|
|
{
|
|
|
|
int err = 0;
|
|
|
|
int i;
|
|
|
|
|
|
|
|
for (i = 0; ptr[i] && !err; i++)
|
|
|
|
err = sysfs_create_file(kobj, ptr[i]);
|
|
|
|
if (err)
|
|
|
|
while (--i >= 0)
|
|
|
|
sysfs_remove_file(kobj, ptr[i]);
|
|
|
|
return err;
|
|
|
|
}
|
2013-08-21 23:17:47 +00:00
|
|
|
EXPORT_SYMBOL_GPL(sysfs_create_files);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-02-20 20:02:44 +00:00
|
|
|
/**
|
|
|
|
* sysfs_add_file_to_group - add an attribute file to a pre-existing group.
|
|
|
|
* @kobj: object we're acting for.
|
|
|
|
* @attr: attribute descriptor.
|
|
|
|
* @group: group name.
|
|
|
|
*/
|
|
|
|
int sysfs_add_file_to_group(struct kobject *kobj,
|
|
|
|
const struct attribute *attr, const char *group)
|
|
|
|
{
|
2007-06-13 19:27:22 +00:00
|
|
|
struct sysfs_dirent *dir_sd;
|
2007-02-20 20:02:44 +00:00
|
|
|
int error;
|
|
|
|
|
2008-01-03 00:44:05 +00:00
|
|
|
if (group)
|
2013-09-12 03:19:13 +00:00
|
|
|
dir_sd = sysfs_get_dirent(kobj->sd, group);
|
2008-01-03 00:44:05 +00:00
|
|
|
else
|
|
|
|
dir_sd = sysfs_get(kobj->sd);
|
|
|
|
|
2007-06-13 19:27:22 +00:00
|
|
|
if (!dir_sd)
|
|
|
|
return -ENOENT;
|
|
|
|
|
|
|
|
error = sysfs_add_file(dir_sd, attr, SYSFS_KOBJ_ATTR);
|
|
|
|
sysfs_put(dir_sd);
|
|
|
|
|
2007-02-20 20:02:44 +00:00
|
|
|
return error;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_add_file_to_group);
|
|
|
|
|
2005-04-19 04:57:32 +00:00
|
|
|
/**
|
|
|
|
* sysfs_chmod_file - update the modified mode value on an object attribute.
|
|
|
|
* @kobj: object we're acting for.
|
|
|
|
* @attr: attribute descriptor.
|
|
|
|
* @mode: file permissions.
|
|
|
|
*
|
|
|
|
*/
|
2010-07-02 14:54:05 +00:00
|
|
|
int sysfs_chmod_file(struct kobject *kobj, const struct attribute *attr,
|
2011-07-24 07:40:40 +00:00
|
|
|
umode_t mode)
|
2005-04-19 04:57:32 +00:00
|
|
|
{
|
2009-11-21 00:08:54 +00:00
|
|
|
struct sysfs_dirent *sd;
|
2005-07-29 19:13:35 +00:00
|
|
|
struct iattr newattrs;
|
2007-06-13 19:27:25 +00:00
|
|
|
int rc;
|
|
|
|
|
2009-11-21 00:08:54 +00:00
|
|
|
mutex_lock(&sysfs_mutex);
|
2007-06-13 19:27:25 +00:00
|
|
|
|
2009-11-21 00:08:54 +00:00
|
|
|
rc = -ENOENT;
|
2013-09-12 02:29:09 +00:00
|
|
|
sd = sysfs_find_dirent(kobj->sd, attr->name, NULL);
|
2009-11-21 00:08:54 +00:00
|
|
|
if (!sd)
|
2007-06-13 19:27:25 +00:00
|
|
|
goto out;
|
2007-09-20 07:05:10 +00:00
|
|
|
|
2009-11-21 00:08:54 +00:00
|
|
|
newattrs.ia_mode = (mode & S_IALLUGO) | (sd->s_mode & ~S_IALLUGO);
|
2009-11-08 07:27:02 +00:00
|
|
|
newattrs.ia_valid = ATTR_MODE;
|
2009-11-21 00:08:54 +00:00
|
|
|
rc = sysfs_sd_setattr(sd, &newattrs);
|
2007-09-20 07:05:10 +00:00
|
|
|
|
2007-06-13 19:27:25 +00:00
|
|
|
out:
|
2009-11-21 00:08:54 +00:00
|
|
|
mutex_unlock(&sysfs_mutex);
|
2007-06-13 19:27:25 +00:00
|
|
|
return rc;
|
2005-04-19 04:57:32 +00:00
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_chmod_file);
|
|
|
|
|
2005-04-16 22:20:36 +00:00
|
|
|
/**
|
2013-09-12 02:29:04 +00:00
|
|
|
* sysfs_remove_file_ns - remove an object attribute with a custom ns tag
|
|
|
|
* @kobj: object we're acting for
|
|
|
|
* @attr: attribute descriptor
|
|
|
|
* @ns: namespace tag of the file to remove
|
2005-04-16 22:20:36 +00:00
|
|
|
*
|
2013-09-12 02:29:04 +00:00
|
|
|
* Hash the attribute name and namespace tag and kill the victim.
|
2005-04-16 22:20:36 +00:00
|
|
|
*/
|
2013-09-12 02:29:04 +00:00
|
|
|
void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
|
|
|
|
const void *ns)
|
2005-04-16 22:20:36 +00:00
|
|
|
{
|
2013-09-12 02:29:04 +00:00
|
|
|
struct sysfs_dirent *dir_sd = kobj->sd;
|
2011-10-12 21:53:38 +00:00
|
|
|
|
2013-09-12 02:29:09 +00:00
|
|
|
sysfs_hash_and_remove(dir_sd, attr->name, ns);
|
2005-04-16 22:20:36 +00:00
|
|
|
}
|
2013-09-12 02:29:04 +00:00
|
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2013-08-21 23:28:26 +00:00
|
|
|
void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
|
2010-01-05 11:48:01 +00:00
|
|
|
{
|
|
|
|
int i;
|
|
|
|
for (i = 0; ptr[i]; i++)
|
|
|
|
sysfs_remove_file(kobj, ptr[i]);
|
|
|
|
}
|
2013-08-21 23:17:47 +00:00
|
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_files);
|
2005-04-16 22:20:36 +00:00
|
|
|
|
2007-02-20 20:02:44 +00:00
|
|
|
/**
|
|
|
|
* sysfs_remove_file_from_group - remove an attribute file from a group.
|
|
|
|
* @kobj: object we're acting for.
|
|
|
|
* @attr: attribute descriptor.
|
|
|
|
* @group: group name.
|
|
|
|
*/
|
|
|
|
void sysfs_remove_file_from_group(struct kobject *kobj,
|
|
|
|
const struct attribute *attr, const char *group)
|
|
|
|
{
|
2007-06-13 19:27:22 +00:00
|
|
|
struct sysfs_dirent *dir_sd;
|
2007-02-20 20:02:44 +00:00
|
|
|
|
2008-01-03 00:44:05 +00:00
|
|
|
if (group)
|
2013-09-12 03:19:13 +00:00
|
|
|
dir_sd = sysfs_get_dirent(kobj->sd, group);
|
2008-01-03 00:44:05 +00:00
|
|
|
else
|
|
|
|
dir_sd = sysfs_get(kobj->sd);
|
2007-06-13 19:27:22 +00:00
|
|
|
if (dir_sd) {
|
2013-09-12 02:29:09 +00:00
|
|
|
sysfs_hash_and_remove(dir_sd, attr->name, NULL);
|
2007-06-13 19:27:22 +00:00
|
|
|
sysfs_put(dir_sd);
|
2007-02-20 20:02:44 +00:00
|
|
|
}
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_remove_file_from_group);
|
|
|
|
|
2007-03-15 19:50:34 +00:00
|
|
|
struct sysfs_schedule_callback_struct {
|
2009-03-13 18:07:36 +00:00
|
|
|
struct list_head workq_list;
|
|
|
|
struct kobject *kobj;
|
2007-03-15 19:50:34 +00:00
|
|
|
void (*func)(void *);
|
|
|
|
void *data;
|
2007-04-26 07:12:04 +00:00
|
|
|
struct module *owner;
|
2007-03-15 19:50:34 +00:00
|
|
|
struct work_struct work;
|
|
|
|
};
|
|
|
|
|
sysfs: don't use global workqueue in sysfs_schedule_callback()
A sysfs attribute using sysfs_schedule_callback() to commit suicide
may end up calling device_unregister(), which will eventually call
a driver's ->remove function.
Drivers may call flush_scheduled_work() in their shutdown routines,
in which case lockdep will complain with something like the following:
=============================================
[ INFO: possible recursive locking detected ]
2.6.29-rc8-kk #1
---------------------------------------------
events/4/56 is trying to acquire lock:
(events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
but task is already holding lock:
(events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
other info that might help us debug this:
3 locks held by events/4/56:
#0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
stack backtrace:
Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1
Call Trace:
[<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260
[<ffffffff8026eade>] __lock_acquire+0x42e/0xa40
[<ffffffff8026f148>] lock_acquire+0x58/0x80
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff8025800d>] flush_workqueue+0x4d/0xa0
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff80258070>] flush_scheduled_work+0x10/0x20
[<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e]
[<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50
[<ffffffff803bfeb2>] pci_device_remove+0x32/0x70
[<ffffffff80441da9>] __device_release_driver+0x59/0x90
[<ffffffff80441edb>] device_release_driver+0x2b/0x40
[<ffffffff804419d6>] bus_remove_device+0xa6/0x120
[<ffffffff8043e46b>] device_del+0x12b/0x190
[<ffffffff8043e4f6>] device_unregister+0x26/0x70
[<ffffffff803ba969>] pci_stop_dev+0x49/0x60
[<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0
[<ffffffff803c10d9>] remove_callback+0x29/0x40
[<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50
[<ffffffff8025769a>] run_workqueue+0x15a/0x230
[<ffffffff80257648>] ? run_workqueue+0x108/0x230
[<ffffffff8025846f>] worker_thread+0x9f/0x100
[<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff802583d0>] ? worker_thread+0x0/0x100
[<ffffffff8025b89d>] kthread+0x4d/0x80
[<ffffffff8020d4ba>] child_rip+0xa/0x20
[<ffffffff8020cebc>] ? restore_args+0x0/0x30
[<ffffffff8025b850>] ? kthread+0x0/0x80
[<ffffffff8020d4b0>] ? child_rip+0x0/0x20
Although we know that the device_unregister path will never acquire
a lock that a driver might try to acquire in its ->remove, in general
we should never attempt to flush a workqueue from within the same
workqueue, and lockdep rightly complains.
So as long as sysfs attributes cannot commit suicide directly and we
are stuck with this callback mechanism, put the sysfs callbacks on
their own workqueue instead of the global one.
This has the side benefit that if a suicidal sysfs attribute kicks
off a long chain of ->remove callbacks, we no longer induce a long
delay on the global queue.
This also fixes a missing module_put in the error path introduced
by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch.
We never destroy the workqueue, but I'm not sure that's a
problem.
Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25 21:11:36 +00:00
|
|
|
static struct workqueue_struct *sysfs_workqueue;
|
2009-03-13 18:07:36 +00:00
|
|
|
static DEFINE_MUTEX(sysfs_workq_mutex);
|
|
|
|
static LIST_HEAD(sysfs_workq);
|
2007-03-15 19:50:34 +00:00
|
|
|
static void sysfs_schedule_callback_work(struct work_struct *work)
|
|
|
|
{
|
|
|
|
struct sysfs_schedule_callback_struct *ss = container_of(work,
|
|
|
|
struct sysfs_schedule_callback_struct, work);
|
|
|
|
|
|
|
|
(ss->func)(ss->data);
|
|
|
|
kobject_put(ss->kobj);
|
2007-04-26 07:12:04 +00:00
|
|
|
module_put(ss->owner);
|
2009-03-13 18:07:36 +00:00
|
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
|
|
list_del(&ss->workq_list);
|
|
|
|
mutex_unlock(&sysfs_workq_mutex);
|
2007-03-15 19:50:34 +00:00
|
|
|
kfree(ss);
|
|
|
|
}
|
|
|
|
|
|
|
|
/**
|
|
|
|
* sysfs_schedule_callback - helper to schedule a callback for a kobject
|
|
|
|
* @kobj: object we're acting for.
|
|
|
|
* @func: callback function to invoke later.
|
|
|
|
* @data: argument to pass to @func.
|
2007-04-26 07:12:04 +00:00
|
|
|
* @owner: module owning the callback code
|
2007-03-15 19:50:34 +00:00
|
|
|
*
|
|
|
|
* sysfs attribute methods must not unregister themselves or their parent
|
|
|
|
* kobject (which would amount to the same thing). Attempts to do so will
|
|
|
|
* deadlock, since unregistration is mutually exclusive with driver
|
|
|
|
* callbacks.
|
|
|
|
*
|
|
|
|
* Instead methods can call this routine, which will attempt to allocate
|
|
|
|
* and schedule a workqueue request to call back @func with @data as its
|
|
|
|
* argument in the workqueue's process context. @kobj will be pinned
|
|
|
|
* until @func returns.
|
|
|
|
*
|
|
|
|
* Returns 0 if the request was submitted, -ENOMEM if storage could not
|
2009-03-13 18:07:36 +00:00
|
|
|
* be allocated, -ENODEV if a reference to @owner isn't available,
|
|
|
|
* -EAGAIN if a callback has already been scheduled for @kobj.
|
2007-03-15 19:50:34 +00:00
|
|
|
*/
|
|
|
|
int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
|
2007-04-26 07:12:04 +00:00
|
|
|
void *data, struct module *owner)
|
2007-03-15 19:50:34 +00:00
|
|
|
{
|
2009-03-13 18:07:36 +00:00
|
|
|
struct sysfs_schedule_callback_struct *ss, *tmp;
|
2007-03-15 19:50:34 +00:00
|
|
|
|
2007-04-26 07:12:04 +00:00
|
|
|
if (!try_module_get(owner))
|
|
|
|
return -ENODEV;
|
2009-03-13 18:07:36 +00:00
|
|
|
|
|
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
|
|
list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)
|
|
|
|
if (ss->kobj == kobj) {
|
sysfs: don't use global workqueue in sysfs_schedule_callback()
A sysfs attribute using sysfs_schedule_callback() to commit suicide
may end up calling device_unregister(), which will eventually call
a driver's ->remove function.
Drivers may call flush_scheduled_work() in their shutdown routines,
in which case lockdep will complain with something like the following:
=============================================
[ INFO: possible recursive locking detected ]
2.6.29-rc8-kk #1
---------------------------------------------
events/4/56 is trying to acquire lock:
(events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
but task is already holding lock:
(events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
other info that might help us debug this:
3 locks held by events/4/56:
#0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
stack backtrace:
Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1
Call Trace:
[<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260
[<ffffffff8026eade>] __lock_acquire+0x42e/0xa40
[<ffffffff8026f148>] lock_acquire+0x58/0x80
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff8025800d>] flush_workqueue+0x4d/0xa0
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff80258070>] flush_scheduled_work+0x10/0x20
[<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e]
[<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50
[<ffffffff803bfeb2>] pci_device_remove+0x32/0x70
[<ffffffff80441da9>] __device_release_driver+0x59/0x90
[<ffffffff80441edb>] device_release_driver+0x2b/0x40
[<ffffffff804419d6>] bus_remove_device+0xa6/0x120
[<ffffffff8043e46b>] device_del+0x12b/0x190
[<ffffffff8043e4f6>] device_unregister+0x26/0x70
[<ffffffff803ba969>] pci_stop_dev+0x49/0x60
[<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0
[<ffffffff803c10d9>] remove_callback+0x29/0x40
[<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50
[<ffffffff8025769a>] run_workqueue+0x15a/0x230
[<ffffffff80257648>] ? run_workqueue+0x108/0x230
[<ffffffff8025846f>] worker_thread+0x9f/0x100
[<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff802583d0>] ? worker_thread+0x0/0x100
[<ffffffff8025b89d>] kthread+0x4d/0x80
[<ffffffff8020d4ba>] child_rip+0xa/0x20
[<ffffffff8020cebc>] ? restore_args+0x0/0x30
[<ffffffff8025b850>] ? kthread+0x0/0x80
[<ffffffff8020d4b0>] ? child_rip+0x0/0x20
Although we know that the device_unregister path will never acquire
a lock that a driver might try to acquire in its ->remove, in general
we should never attempt to flush a workqueue from within the same
workqueue, and lockdep rightly complains.
So as long as sysfs attributes cannot commit suicide directly and we
are stuck with this callback mechanism, put the sysfs callbacks on
their own workqueue instead of the global one.
This has the side benefit that if a suicidal sysfs attribute kicks
off a long chain of ->remove callbacks, we no longer induce a long
delay on the global queue.
This also fixes a missing module_put in the error path introduced
by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch.
We never destroy the workqueue, but I'm not sure that's a
problem.
Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25 21:11:36 +00:00
|
|
|
module_put(owner);
|
2009-03-13 18:07:36 +00:00
|
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
|
|
return -EAGAIN;
|
|
|
|
}
|
|
|
|
mutex_unlock(&sysfs_workq_mutex);
|
|
|
|
|
sysfs: don't use global workqueue in sysfs_schedule_callback()
A sysfs attribute using sysfs_schedule_callback() to commit suicide
may end up calling device_unregister(), which will eventually call
a driver's ->remove function.
Drivers may call flush_scheduled_work() in their shutdown routines,
in which case lockdep will complain with something like the following:
=============================================
[ INFO: possible recursive locking detected ]
2.6.29-rc8-kk #1
---------------------------------------------
events/4/56 is trying to acquire lock:
(events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
but task is already holding lock:
(events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
other info that might help us debug this:
3 locks held by events/4/56:
#0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
stack backtrace:
Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1
Call Trace:
[<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260
[<ffffffff8026eade>] __lock_acquire+0x42e/0xa40
[<ffffffff8026f148>] lock_acquire+0x58/0x80
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff8025800d>] flush_workqueue+0x4d/0xa0
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff80258070>] flush_scheduled_work+0x10/0x20
[<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e]
[<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50
[<ffffffff803bfeb2>] pci_device_remove+0x32/0x70
[<ffffffff80441da9>] __device_release_driver+0x59/0x90
[<ffffffff80441edb>] device_release_driver+0x2b/0x40
[<ffffffff804419d6>] bus_remove_device+0xa6/0x120
[<ffffffff8043e46b>] device_del+0x12b/0x190
[<ffffffff8043e4f6>] device_unregister+0x26/0x70
[<ffffffff803ba969>] pci_stop_dev+0x49/0x60
[<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0
[<ffffffff803c10d9>] remove_callback+0x29/0x40
[<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50
[<ffffffff8025769a>] run_workqueue+0x15a/0x230
[<ffffffff80257648>] ? run_workqueue+0x108/0x230
[<ffffffff8025846f>] worker_thread+0x9f/0x100
[<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff802583d0>] ? worker_thread+0x0/0x100
[<ffffffff8025b89d>] kthread+0x4d/0x80
[<ffffffff8020d4ba>] child_rip+0xa/0x20
[<ffffffff8020cebc>] ? restore_args+0x0/0x30
[<ffffffff8025b850>] ? kthread+0x0/0x80
[<ffffffff8020d4b0>] ? child_rip+0x0/0x20
Although we know that the device_unregister path will never acquire
a lock that a driver might try to acquire in its ->remove, in general
we should never attempt to flush a workqueue from within the same
workqueue, and lockdep rightly complains.
So as long as sysfs attributes cannot commit suicide directly and we
are stuck with this callback mechanism, put the sysfs callbacks on
their own workqueue instead of the global one.
This has the side benefit that if a suicidal sysfs attribute kicks
off a long chain of ->remove callbacks, we no longer induce a long
delay on the global queue.
This also fixes a missing module_put in the error path introduced
by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch.
We never destroy the workqueue, but I'm not sure that's a
problem.
Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25 21:11:36 +00:00
|
|
|
if (sysfs_workqueue == NULL) {
|
2009-05-07 19:36:53 +00:00
|
|
|
sysfs_workqueue = create_singlethread_workqueue("sysfsd");
|
sysfs: don't use global workqueue in sysfs_schedule_callback()
A sysfs attribute using sysfs_schedule_callback() to commit suicide
may end up calling device_unregister(), which will eventually call
a driver's ->remove function.
Drivers may call flush_scheduled_work() in their shutdown routines,
in which case lockdep will complain with something like the following:
=============================================
[ INFO: possible recursive locking detected ]
2.6.29-rc8-kk #1
---------------------------------------------
events/4/56 is trying to acquire lock:
(events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
but task is already holding lock:
(events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
other info that might help us debug this:
3 locks held by events/4/56:
#0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
stack backtrace:
Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1
Call Trace:
[<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260
[<ffffffff8026eade>] __lock_acquire+0x42e/0xa40
[<ffffffff8026f148>] lock_acquire+0x58/0x80
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff8025800d>] flush_workqueue+0x4d/0xa0
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff80258070>] flush_scheduled_work+0x10/0x20
[<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e]
[<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50
[<ffffffff803bfeb2>] pci_device_remove+0x32/0x70
[<ffffffff80441da9>] __device_release_driver+0x59/0x90
[<ffffffff80441edb>] device_release_driver+0x2b/0x40
[<ffffffff804419d6>] bus_remove_device+0xa6/0x120
[<ffffffff8043e46b>] device_del+0x12b/0x190
[<ffffffff8043e4f6>] device_unregister+0x26/0x70
[<ffffffff803ba969>] pci_stop_dev+0x49/0x60
[<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0
[<ffffffff803c10d9>] remove_callback+0x29/0x40
[<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50
[<ffffffff8025769a>] run_workqueue+0x15a/0x230
[<ffffffff80257648>] ? run_workqueue+0x108/0x230
[<ffffffff8025846f>] worker_thread+0x9f/0x100
[<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff802583d0>] ? worker_thread+0x0/0x100
[<ffffffff8025b89d>] kthread+0x4d/0x80
[<ffffffff8020d4ba>] child_rip+0xa/0x20
[<ffffffff8020cebc>] ? restore_args+0x0/0x30
[<ffffffff8025b850>] ? kthread+0x0/0x80
[<ffffffff8020d4b0>] ? child_rip+0x0/0x20
Although we know that the device_unregister path will never acquire
a lock that a driver might try to acquire in its ->remove, in general
we should never attempt to flush a workqueue from within the same
workqueue, and lockdep rightly complains.
So as long as sysfs attributes cannot commit suicide directly and we
are stuck with this callback mechanism, put the sysfs callbacks on
their own workqueue instead of the global one.
This has the side benefit that if a suicidal sysfs attribute kicks
off a long chain of ->remove callbacks, we no longer induce a long
delay on the global queue.
This also fixes a missing module_put in the error path introduced
by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch.
We never destroy the workqueue, but I'm not sure that's a
problem.
Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25 21:11:36 +00:00
|
|
|
if (sysfs_workqueue == NULL) {
|
|
|
|
module_put(owner);
|
|
|
|
return -ENOMEM;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
2007-03-15 19:50:34 +00:00
|
|
|
ss = kmalloc(sizeof(*ss), GFP_KERNEL);
|
2007-04-26 07:12:04 +00:00
|
|
|
if (!ss) {
|
|
|
|
module_put(owner);
|
2007-03-15 19:50:34 +00:00
|
|
|
return -ENOMEM;
|
2007-04-26 07:12:04 +00:00
|
|
|
}
|
2007-03-15 19:50:34 +00:00
|
|
|
kobject_get(kobj);
|
|
|
|
ss->kobj = kobj;
|
|
|
|
ss->func = func;
|
|
|
|
ss->data = data;
|
2007-04-26 07:12:04 +00:00
|
|
|
ss->owner = owner;
|
2007-03-15 19:50:34 +00:00
|
|
|
INIT_WORK(&ss->work, sysfs_schedule_callback_work);
|
2009-03-13 18:07:36 +00:00
|
|
|
INIT_LIST_HEAD(&ss->workq_list);
|
|
|
|
mutex_lock(&sysfs_workq_mutex);
|
|
|
|
list_add_tail(&ss->workq_list, &sysfs_workq);
|
|
|
|
mutex_unlock(&sysfs_workq_mutex);
|
sysfs: don't use global workqueue in sysfs_schedule_callback()
A sysfs attribute using sysfs_schedule_callback() to commit suicide
may end up calling device_unregister(), which will eventually call
a driver's ->remove function.
Drivers may call flush_scheduled_work() in their shutdown routines,
in which case lockdep will complain with something like the following:
=============================================
[ INFO: possible recursive locking detected ]
2.6.29-rc8-kk #1
---------------------------------------------
events/4/56 is trying to acquire lock:
(events){--..}, at: [<ffffffff80257fc0>] flush_workqueue+0x0/0xa0
but task is already holding lock:
(events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
other info that might help us debug this:
3 locks held by events/4/56:
#0: (events){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#1: (&ss->work){--..}, at: [<ffffffff80257648>] run_workqueue+0x108/0x230
#2: (pci_remove_rescan_mutex){--..}, at: [<ffffffff803c10d1>] remove_callback+0x21/0x40
stack backtrace:
Pid: 56, comm: events/4 Not tainted 2.6.29-rc8-kk #1
Call Trace:
[<ffffffff8026dfcd>] validate_chain+0xb7d/0x1260
[<ffffffff8026eade>] __lock_acquire+0x42e/0xa40
[<ffffffff8026f148>] lock_acquire+0x58/0x80
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff8025800d>] flush_workqueue+0x4d/0xa0
[<ffffffff80257fc0>] ? flush_workqueue+0x0/0xa0
[<ffffffff80258070>] flush_scheduled_work+0x10/0x20
[<ffffffffa0144065>] e1000_remove+0x55/0xfe [e1000e]
[<ffffffff8033ee30>] ? sysfs_schedule_callback_work+0x0/0x50
[<ffffffff803bfeb2>] pci_device_remove+0x32/0x70
[<ffffffff80441da9>] __device_release_driver+0x59/0x90
[<ffffffff80441edb>] device_release_driver+0x2b/0x40
[<ffffffff804419d6>] bus_remove_device+0xa6/0x120
[<ffffffff8043e46b>] device_del+0x12b/0x190
[<ffffffff8043e4f6>] device_unregister+0x26/0x70
[<ffffffff803ba969>] pci_stop_dev+0x49/0x60
[<ffffffff803baab0>] pci_remove_bus_device+0x40/0xc0
[<ffffffff803c10d9>] remove_callback+0x29/0x40
[<ffffffff8033ee4f>] sysfs_schedule_callback_work+0x1f/0x50
[<ffffffff8025769a>] run_workqueue+0x15a/0x230
[<ffffffff80257648>] ? run_workqueue+0x108/0x230
[<ffffffff8025846f>] worker_thread+0x9f/0x100
[<ffffffff8025bce0>] ? autoremove_wake_function+0x0/0x40
[<ffffffff802583d0>] ? worker_thread+0x0/0x100
[<ffffffff8025b89d>] kthread+0x4d/0x80
[<ffffffff8020d4ba>] child_rip+0xa/0x20
[<ffffffff8020cebc>] ? restore_args+0x0/0x30
[<ffffffff8025b850>] ? kthread+0x0/0x80
[<ffffffff8020d4b0>] ? child_rip+0x0/0x20
Although we know that the device_unregister path will never acquire
a lock that a driver might try to acquire in its ->remove, in general
we should never attempt to flush a workqueue from within the same
workqueue, and lockdep rightly complains.
So as long as sysfs attributes cannot commit suicide directly and we
are stuck with this callback mechanism, put the sysfs callbacks on
their own workqueue instead of the global one.
This has the side benefit that if a suicidal sysfs attribute kicks
off a long chain of ->remove callbacks, we no longer induce a long
delay on the global queue.
This also fixes a missing module_put in the error path introduced
by sysfs-only-allow-one-scheduled-removal-callback-per-kobj.patch.
We never destroy the workqueue, but I'm not sure that's a
problem.
Reported-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Tested-by: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Signed-off-by: Alex Chiang <achiang@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2009-03-25 21:11:36 +00:00
|
|
|
queue_work(sysfs_workqueue, &ss->work);
|
2007-03-15 19:50:34 +00:00
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
|