kernel-ark/drivers/edac/edac_device.c
Jesper Dangaard Brouer 458e5ff13e edac: core: remove completion-wait for complete with rcu_barrier
Module edac_core.ko uses call_rcu() callbacks in edac_device.c, edac_mc.c
and edac_pci.c.

They all use a wait_for_completion() scheme, but this scheme it not 100%
safe on multiple CPUs.  See the _rcu_barrier() implementation which
explains why extra precausion is needed.

The patch adds a comment about rcu_barrier() and as a precausion calls
rcu_barrier().  A maintainer needs to look at removing the
wait_for_completion code.

[dougthompson@xmission.com: remove the wait_for_completion code]
Signed-off-by Jesper Dangaard Brouer <hawk@comx.dk>
Signed-off-by: Doug Thompson <dougthompson@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-09-24 07:21:05 -07:00

737 lines
20 KiB
C

/*
* edac_device.c
* (C) 2007 www.douglaskthompson.com
*
* This file may be distributed under the terms of the
* GNU General Public License.
*
* Written by Doug Thompson <norsk5@xmission.com>
*
* edac_device API implementation
* 19 Jan 2007
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/sysctl.h>
#include <linux/highmem.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sysdev.h>
#include <linux/ctype.h>
#include <linux/workqueue.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#include "edac_core.h"
#include "edac_module.h"
/* lock for the list: 'edac_device_list', manipulation of this list
* is protected by the 'device_ctls_mutex' lock
*/
static DEFINE_MUTEX(device_ctls_mutex);
static LIST_HEAD(edac_device_list);
#ifdef CONFIG_EDAC_DEBUG
static void edac_device_dump_device(struct edac_device_ctl_info *edac_dev)
{
debugf3("\tedac_dev = %p dev_idx=%d \n", edac_dev, edac_dev->dev_idx);
debugf4("\tedac_dev->edac_check = %p\n", edac_dev->edac_check);
debugf3("\tdev = %p\n", edac_dev->dev);
debugf3("\tmod_name:ctl_name = %s:%s\n",
edac_dev->mod_name, edac_dev->ctl_name);
debugf3("\tpvt_info = %p\n\n", edac_dev->pvt_info);
}
#endif /* CONFIG_EDAC_DEBUG */
/*
* edac_device_alloc_ctl_info()
* Allocate a new edac device control info structure
*
* The control structure is allocated in complete chunk
* from the OS. It is in turn sub allocated to the
* various objects that compose the struture
*
* The structure has a 'nr_instance' array within itself.
* Each instance represents a major component
* Example: L1 cache and L2 cache are 2 instance components
*
* Within each instance is an array of 'nr_blocks' blockoffsets
*/
struct edac_device_ctl_info *edac_device_alloc_ctl_info(
unsigned sz_private,
char *edac_device_name, unsigned nr_instances,
char *edac_block_name, unsigned nr_blocks,
unsigned offset_value, /* zero, 1, or other based offset */
struct edac_dev_sysfs_block_attribute *attrib_spec, unsigned nr_attrib,
int device_index)
{
struct edac_device_ctl_info *dev_ctl;
struct edac_device_instance *dev_inst, *inst;
struct edac_device_block *dev_blk, *blk_p, *blk;
struct edac_dev_sysfs_block_attribute *dev_attrib, *attrib_p, *attrib;
unsigned total_size;
unsigned count;
unsigned instance, block, attr;
void *pvt;
int err;
debugf4("%s() instances=%d blocks=%d\n",
__func__, nr_instances, nr_blocks);
/* Calculate the size of memory we need to allocate AND
* determine the offsets of the various item arrays
* (instance,block,attrib) from the start of an allocated structure.
* We want the alignment of each item (instance,block,attrib)
* to be at least as stringent as what the compiler would
* provide if we could simply hardcode everything into a single struct.
*/
dev_ctl = (struct edac_device_ctl_info *)NULL;
/* Calc the 'end' offset past end of ONE ctl_info structure
* which will become the start of the 'instance' array
*/
dev_inst = edac_align_ptr(&dev_ctl[1], sizeof(*dev_inst));
/* Calc the 'end' offset past the instance array within the ctl_info
* which will become the start of the block array
*/
dev_blk = edac_align_ptr(&dev_inst[nr_instances], sizeof(*dev_blk));
/* Calc the 'end' offset past the dev_blk array
* which will become the start of the attrib array, if any.
*/
count = nr_instances * nr_blocks;
dev_attrib = edac_align_ptr(&dev_blk[count], sizeof(*dev_attrib));
/* Check for case of when an attribute array is specified */
if (nr_attrib > 0) {
/* calc how many nr_attrib we need */
count *= nr_attrib;
/* Calc the 'end' offset past the attributes array */
pvt = edac_align_ptr(&dev_attrib[count], sz_private);
} else {
/* no attribute array specificed */
pvt = edac_align_ptr(dev_attrib, sz_private);
}
/* 'pvt' now points to where the private data area is.
* At this point 'pvt' (like dev_inst,dev_blk and dev_attrib)
* is baselined at ZERO
*/
total_size = ((unsigned long)pvt) + sz_private;
/* Allocate the amount of memory for the set of control structures */
dev_ctl = kzalloc(total_size, GFP_KERNEL);
if (dev_ctl == NULL)
return NULL;
/* Adjust pointers so they point within the actual memory we
* just allocated rather than an imaginary chunk of memory
* located at address 0.
* 'dev_ctl' points to REAL memory, while the others are
* ZERO based and thus need to be adjusted to point within
* the allocated memory.
*/
dev_inst = (struct edac_device_instance *)
(((char *)dev_ctl) + ((unsigned long)dev_inst));
dev_blk = (struct edac_device_block *)
(((char *)dev_ctl) + ((unsigned long)dev_blk));
dev_attrib = (struct edac_dev_sysfs_block_attribute *)
(((char *)dev_ctl) + ((unsigned long)dev_attrib));
pvt = sz_private ? (((char *)dev_ctl) + ((unsigned long)pvt)) : NULL;
/* Begin storing the information into the control info structure */
dev_ctl->dev_idx = device_index;
dev_ctl->nr_instances = nr_instances;
dev_ctl->instances = dev_inst;
dev_ctl->pvt_info = pvt;
/* Default logging of CEs and UEs */
dev_ctl->log_ce = 1;
dev_ctl->log_ue = 1;
/* Name of this edac device */
snprintf(dev_ctl->name,sizeof(dev_ctl->name),"%s",edac_device_name);
debugf4("%s() edac_dev=%p next after end=%p\n",
__func__, dev_ctl, pvt + sz_private );
/* Initialize every Instance */
for (instance = 0; instance < nr_instances; instance++) {
inst = &dev_inst[instance];
inst->ctl = dev_ctl;
inst->nr_blocks = nr_blocks;
blk_p = &dev_blk[instance * nr_blocks];
inst->blocks = blk_p;
/* name of this instance */
snprintf(inst->name, sizeof(inst->name),
"%s%u", edac_device_name, instance);
/* Initialize every block in each instance */
for (block = 0; block < nr_blocks; block++) {
blk = &blk_p[block];
blk->instance = inst;
snprintf(blk->name, sizeof(blk->name),
"%s%d", edac_block_name, block+offset_value);
debugf4("%s() instance=%d inst_p=%p block=#%d "
"block_p=%p name='%s'\n",
__func__, instance, inst, block,
blk, blk->name);
/* if there are NO attributes OR no attribute pointer
* then continue on to next block iteration
*/
if ((nr_attrib == 0) || (attrib_spec == NULL))
continue;
/* setup the attribute array for this block */
blk->nr_attribs = nr_attrib;
attrib_p = &dev_attrib[block*nr_instances*nr_attrib];
blk->block_attributes = attrib_p;
debugf4("%s() THIS BLOCK_ATTRIB=%p\n",
__func__, blk->block_attributes);
/* Initialize every user specified attribute in this
* block with the data the caller passed in
* Each block gets its own copy of pointers,
* and its unique 'value'
*/
for (attr = 0; attr < nr_attrib; attr++) {
attrib = &attrib_p[attr];
/* populate the unique per attrib
* with the code pointers and info
*/
attrib->attr = attrib_spec[attr].attr;
attrib->show = attrib_spec[attr].show;
attrib->store = attrib_spec[attr].store;
attrib->block = blk; /* up link */
debugf4("%s() alloc-attrib=%p attrib_name='%s' "
"attrib-spec=%p spec-name=%s\n",
__func__, attrib, attrib->attr.name,
&attrib_spec[attr],
attrib_spec[attr].attr.name
);
}
}
}
/* Mark this instance as merely ALLOCATED */
dev_ctl->op_state = OP_ALLOC;
/*
* Initialize the 'root' kobj for the edac_device controller
*/
err = edac_device_register_sysfs_main_kobj(dev_ctl);
if (err) {
kfree(dev_ctl);
return NULL;
}
/* at this point, the root kobj is valid, and in order to
* 'free' the object, then the function:
* edac_device_unregister_sysfs_main_kobj() must be called
* which will perform kobj unregistration and the actual free
* will occur during the kobject callback operation
*/
return dev_ctl;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_ctl_info);
/*
* edac_device_free_ctl_info()
* frees the memory allocated by the edac_device_alloc_ctl_info()
* function
*/
void edac_device_free_ctl_info(struct edac_device_ctl_info *ctl_info)
{
edac_device_unregister_sysfs_main_kobj(ctl_info);
}
EXPORT_SYMBOL_GPL(edac_device_free_ctl_info);
/*
* find_edac_device_by_dev
* scans the edac_device list for a specific 'struct device *'
*
* lock to be held prior to call: device_ctls_mutex
*
* Return:
* pointer to control structure managing 'dev'
* NULL if not found on list
*/
static struct edac_device_ctl_info *find_edac_device_by_dev(struct device *dev)
{
struct edac_device_ctl_info *edac_dev;
struct list_head *item;
debugf0("%s()\n", __func__);
list_for_each(item, &edac_device_list) {
edac_dev = list_entry(item, struct edac_device_ctl_info, link);
if (edac_dev->dev == dev)
return edac_dev;
}
return NULL;
}
/*
* add_edac_dev_to_global_list
* Before calling this function, caller must
* assign a unique value to edac_dev->dev_idx.
*
* lock to be held prior to call: device_ctls_mutex
*
* Return:
* 0 on success
* 1 on failure.
*/
static int add_edac_dev_to_global_list(struct edac_device_ctl_info *edac_dev)
{
struct list_head *item, *insert_before;
struct edac_device_ctl_info *rover;
insert_before = &edac_device_list;
/* Determine if already on the list */
rover = find_edac_device_by_dev(edac_dev->dev);
if (unlikely(rover != NULL))
goto fail0;
/* Insert in ascending order by 'dev_idx', so find position */
list_for_each(item, &edac_device_list) {
rover = list_entry(item, struct edac_device_ctl_info, link);
if (rover->dev_idx >= edac_dev->dev_idx) {
if (unlikely(rover->dev_idx == edac_dev->dev_idx))
goto fail1;
insert_before = item;
break;
}
}
list_add_tail_rcu(&edac_dev->link, insert_before);
return 0;
fail0:
edac_printk(KERN_WARNING, EDAC_MC,
"%s (%s) %s %s already assigned %d\n",
dev_name(rover->dev), edac_dev_name(rover),
rover->mod_name, rover->ctl_name, rover->dev_idx);
return 1;
fail1:
edac_printk(KERN_WARNING, EDAC_MC,
"bug in low-level driver: attempt to assign\n"
" duplicate dev_idx %d in %s()\n", rover->dev_idx,
__func__);
return 1;
}
/*
* complete_edac_device_list_del
*
* callback function when reference count is zero
*/
static void complete_edac_device_list_del(struct rcu_head *head)
{
struct edac_device_ctl_info *edac_dev;
edac_dev = container_of(head, struct edac_device_ctl_info, rcu);
INIT_LIST_HEAD(&edac_dev->link);
}
/*
* del_edac_device_from_global_list
*
* remove the RCU, setup for a callback call,
* then wait for the callback to occur
*/
static void del_edac_device_from_global_list(struct edac_device_ctl_info
*edac_device)
{
list_del_rcu(&edac_device->link);
call_rcu(&edac_device->rcu, complete_edac_device_list_del);
rcu_barrier();
}
/*
* edac_device_workq_function
* performs the operation scheduled by a workq request
*
* this workq is embedded within an edac_device_ctl_info
* structure, that needs to be polled for possible error events.
*
* This operation is to acquire the list mutex lock
* (thus preventing insertation or deletion)
* and then call the device's poll function IFF this device is
* running polled and there is a poll function defined.
*/
static void edac_device_workq_function(struct work_struct *work_req)
{
struct delayed_work *d_work = to_delayed_work(work_req);
struct edac_device_ctl_info *edac_dev = to_edac_device_ctl_work(d_work);
mutex_lock(&device_ctls_mutex);
/* If we are being removed, bail out immediately */
if (edac_dev->op_state == OP_OFFLINE) {
mutex_unlock(&device_ctls_mutex);
return;
}
/* Only poll controllers that are running polled and have a check */
if ((edac_dev->op_state == OP_RUNNING_POLL) &&
(edac_dev->edac_check != NULL)) {
edac_dev->edac_check(edac_dev);
}
mutex_unlock(&device_ctls_mutex);
/* Reschedule the workq for the next time period to start again
* if the number of msec is for 1 sec, then adjust to the next
* whole one second to save timers fireing all over the period
* between integral seconds
*/
if (edac_dev->poll_msec == 1000)
queue_delayed_work(edac_workqueue, &edac_dev->work,
round_jiffies_relative(edac_dev->delay));
else
queue_delayed_work(edac_workqueue, &edac_dev->work,
edac_dev->delay);
}
/*
* edac_device_workq_setup
* initialize a workq item for this edac_device instance
* passing in the new delay period in msec
*/
void edac_device_workq_setup(struct edac_device_ctl_info *edac_dev,
unsigned msec)
{
debugf0("%s()\n", __func__);
/* take the arg 'msec' and set it into the control structure
* to used in the time period calculation
* then calc the number of jiffies that represents
*/
edac_dev->poll_msec = msec;
edac_dev->delay = msecs_to_jiffies(msec);
INIT_DELAYED_WORK(&edac_dev->work, edac_device_workq_function);
/* optimize here for the 1 second case, which will be normal value, to
* fire ON the 1 second time event. This helps reduce all sorts of
* timers firing on sub-second basis, while they are happy
* to fire together on the 1 second exactly
*/
if (edac_dev->poll_msec == 1000)
queue_delayed_work(edac_workqueue, &edac_dev->work,
round_jiffies_relative(edac_dev->delay));
else
queue_delayed_work(edac_workqueue, &edac_dev->work,
edac_dev->delay);
}
/*
* edac_device_workq_teardown
* stop the workq processing on this edac_dev
*/
void edac_device_workq_teardown(struct edac_device_ctl_info *edac_dev)
{
int status;
status = cancel_delayed_work(&edac_dev->work);
if (status == 0) {
/* workq instance might be running, wait for it */
flush_workqueue(edac_workqueue);
}
}
/*
* edac_device_reset_delay_period
*
* need to stop any outstanding workq queued up at this time
* because we will be resetting the sleep time.
* Then restart the workq on the new delay
*/
void edac_device_reset_delay_period(struct edac_device_ctl_info *edac_dev,
unsigned long value)
{
/* cancel the current workq request, without the mutex lock */
edac_device_workq_teardown(edac_dev);
/* acquire the mutex before doing the workq setup */
mutex_lock(&device_ctls_mutex);
/* restart the workq request, with new delay value */
edac_device_workq_setup(edac_dev, value);
mutex_unlock(&device_ctls_mutex);
}
/*
* edac_device_alloc_index: Allocate a unique device index number
*
* Return:
* allocated index number
*/
int edac_device_alloc_index(void)
{
static atomic_t device_indexes = ATOMIC_INIT(0);
return atomic_inc_return(&device_indexes) - 1;
}
EXPORT_SYMBOL_GPL(edac_device_alloc_index);
/**
* edac_device_add_device: Insert the 'edac_dev' structure into the
* edac_device global list and create sysfs entries associated with
* edac_device structure.
* @edac_device: pointer to the edac_device structure to be added to the list
* 'edac_device' structure.
*
* Return:
* 0 Success
* !0 Failure
*/
int edac_device_add_device(struct edac_device_ctl_info *edac_dev)
{
debugf0("%s()\n", __func__);
#ifdef CONFIG_EDAC_DEBUG
if (edac_debug_level >= 3)
edac_device_dump_device(edac_dev);
#endif
mutex_lock(&device_ctls_mutex);
if (add_edac_dev_to_global_list(edac_dev))
goto fail0;
/* set load time so that error rate can be tracked */
edac_dev->start_time = jiffies;
/* create this instance's sysfs entries */
if (edac_device_create_sysfs(edac_dev)) {
edac_device_printk(edac_dev, KERN_WARNING,
"failed to create sysfs device\n");
goto fail1;
}
/* If there IS a check routine, then we are running POLLED */
if (edac_dev->edac_check != NULL) {
/* This instance is NOW RUNNING */
edac_dev->op_state = OP_RUNNING_POLL;
/*
* enable workq processing on this instance,
* default = 1000 msec
*/
edac_device_workq_setup(edac_dev, 1000);
} else {
edac_dev->op_state = OP_RUNNING_INTERRUPT;
}
/* Report action taken */
edac_device_printk(edac_dev, KERN_INFO,
"Giving out device to module '%s' controller "
"'%s': DEV '%s' (%s)\n",
edac_dev->mod_name,
edac_dev->ctl_name,
edac_dev_name(edac_dev),
edac_op_state_to_string(edac_dev->op_state));
mutex_unlock(&device_ctls_mutex);
return 0;
fail1:
/* Some error, so remove the entry from the lsit */
del_edac_device_from_global_list(edac_dev);
fail0:
mutex_unlock(&device_ctls_mutex);
return 1;
}
EXPORT_SYMBOL_GPL(edac_device_add_device);
/**
* edac_device_del_device:
* Remove sysfs entries for specified edac_device structure and
* then remove edac_device structure from global list
*
* @pdev:
* Pointer to 'struct device' representing edac_device
* structure to remove.
*
* Return:
* Pointer to removed edac_device structure,
* OR NULL if device not found.
*/
struct edac_device_ctl_info *edac_device_del_device(struct device *dev)
{
struct edac_device_ctl_info *edac_dev;
debugf0("%s()\n", __func__);
mutex_lock(&device_ctls_mutex);
/* Find the structure on the list, if not there, then leave */
edac_dev = find_edac_device_by_dev(dev);
if (edac_dev == NULL) {
mutex_unlock(&device_ctls_mutex);
return NULL;
}
/* mark this instance as OFFLINE */
edac_dev->op_state = OP_OFFLINE;
/* deregister from global list */
del_edac_device_from_global_list(edac_dev);
mutex_unlock(&device_ctls_mutex);
/* clear workq processing on this instance */
edac_device_workq_teardown(edac_dev);
/* Tear down the sysfs entries for this instance */
edac_device_remove_sysfs(edac_dev);
edac_printk(KERN_INFO, EDAC_MC,
"Removed device %d for %s %s: DEV %s\n",
edac_dev->dev_idx,
edac_dev->mod_name, edac_dev->ctl_name, edac_dev_name(edac_dev));
return edac_dev;
}
EXPORT_SYMBOL_GPL(edac_device_del_device);
static inline int edac_device_get_log_ce(struct edac_device_ctl_info *edac_dev)
{
return edac_dev->log_ce;
}
static inline int edac_device_get_log_ue(struct edac_device_ctl_info *edac_dev)
{
return edac_dev->log_ue;
}
static inline int edac_device_get_panic_on_ue(struct edac_device_ctl_info
*edac_dev)
{
return edac_dev->panic_on_ue;
}
/*
* edac_device_handle_ce
* perform a common output and handling of an 'edac_dev' CE event
*/
void edac_device_handle_ce(struct edac_device_ctl_info *edac_dev,
int inst_nr, int block_nr, const char *msg)
{
struct edac_device_instance *instance;
struct edac_device_block *block = NULL;
if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
edac_device_printk(edac_dev, KERN_ERR,
"INTERNAL ERROR: 'instance' out of range "
"(%d >= %d)\n", inst_nr,
edac_dev->nr_instances);
return;
}
instance = edac_dev->instances + inst_nr;
if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
edac_device_printk(edac_dev, KERN_ERR,
"INTERNAL ERROR: instance %d 'block' "
"out of range (%d >= %d)\n",
inst_nr, block_nr,
instance->nr_blocks);
return;
}
if (instance->nr_blocks > 0) {
block = instance->blocks + block_nr;
block->counters.ce_count++;
}
/* Propogate the count up the 'totals' tree */
instance->counters.ce_count++;
edac_dev->counters.ce_count++;
if (edac_device_get_log_ce(edac_dev))
edac_device_printk(edac_dev, KERN_WARNING,
"CE: %s instance: %s block: %s '%s'\n",
edac_dev->ctl_name, instance->name,
block ? block->name : "N/A", msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ce);
/*
* edac_device_handle_ue
* perform a common output and handling of an 'edac_dev' UE event
*/
void edac_device_handle_ue(struct edac_device_ctl_info *edac_dev,
int inst_nr, int block_nr, const char *msg)
{
struct edac_device_instance *instance;
struct edac_device_block *block = NULL;
if ((inst_nr >= edac_dev->nr_instances) || (inst_nr < 0)) {
edac_device_printk(edac_dev, KERN_ERR,
"INTERNAL ERROR: 'instance' out of range "
"(%d >= %d)\n", inst_nr,
edac_dev->nr_instances);
return;
}
instance = edac_dev->instances + inst_nr;
if ((block_nr >= instance->nr_blocks) || (block_nr < 0)) {
edac_device_printk(edac_dev, KERN_ERR,
"INTERNAL ERROR: instance %d 'block' "
"out of range (%d >= %d)\n",
inst_nr, block_nr,
instance->nr_blocks);
return;
}
if (instance->nr_blocks > 0) {
block = instance->blocks + block_nr;
block->counters.ue_count++;
}
/* Propogate the count up the 'totals' tree */
instance->counters.ue_count++;
edac_dev->counters.ue_count++;
if (edac_device_get_log_ue(edac_dev))
edac_device_printk(edac_dev, KERN_EMERG,
"UE: %s instance: %s block: %s '%s'\n",
edac_dev->ctl_name, instance->name,
block ? block->name : "N/A", msg);
if (edac_device_get_panic_on_ue(edac_dev))
panic("EDAC %s: UE instance: %s block %s '%s'\n",
edac_dev->ctl_name, instance->name,
block ? block->name : "N/A", msg);
}
EXPORT_SYMBOL_GPL(edac_device_handle_ue);