kernel-ark/net/unix/garbage.c
Tim Schmielau cd354f1ae7 [PATCH] remove many unneeded #includes of sched.h
After Al Viro (finally) succeeded in removing the sched.h #include in module.h
recently, it makes sense again to remove other superfluous sched.h includes.
There are quite a lot of files which include it but don't actually need
anything defined in there.  Presumably these includes were once needed for
macros that used to live in sched.h, but moved to other header files in the
course of cleaning it up.

To ease the pain, this time I did not fiddle with any header files and only
removed #includes from .c-files, which tend to cause less trouble.

Compile tested against 2.6.20-rc2 and 2.6.20-rc2-mm2 (with offsets) on alpha,
arm, i386, ia64, mips, powerpc, and x86_64 with allnoconfig, defconfig,
allmodconfig, and allyesconfig as well as a few randconfigs on x86_64 and all
configs in arch/arm/configs on arm.  I also checked that no new warnings were
introduced by the patch (actually, some warnings are removed that were emitted
by unnecessarily included header files).

Signed-off-by: Tim Schmielau <tim@physik3.uni-rostock.de>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-14 08:09:54 -08:00

313 lines
7.3 KiB
C

/*
* NET3: Garbage Collector For AF_UNIX sockets
*
* Garbage Collector:
* Copyright (C) Barak A. Pearlmutter.
* Released under the GPL version 2 or later.
*
* Chopped about by Alan Cox 22/3/96 to make it fit the AF_UNIX socket problem.
* If it doesn't work blame me, it worked when Barak sent it.
*
* Assumptions:
*
* - object w/ a bit
* - free list
*
* Current optimizations:
*
* - explicit stack instead of recursion
* - tail recurse on first born instead of immediate push/pop
* - we gather the stuff that should not be killed into tree
* and stack is just a path from root to the current pointer.
*
* Future optimizations:
*
* - don't just push entire root set; process in place
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Fixes:
* Alan Cox 07 Sept 1997 Vmalloc internal stack as needed.
* Cope with changing max_files.
* Al Viro 11 Oct 1998
* Graph may have cycles. That is, we can send the descriptor
* of foo to bar and vice versa. Current code chokes on that.
* Fix: move SCM_RIGHTS ones into the separate list and then
* skb_free() them all instead of doing explicit fput's.
* Another problem: since fput() may block somebody may
* create a new unix_socket when we are in the middle of sweep
* phase. Fix: revert the logic wrt MARKED. Mark everything
* upon the beginning and unmark non-junk ones.
*
* [12 Oct 1998] AAARGH! New code purges all SCM_RIGHTS
* sent to connect()'ed but still not accept()'ed sockets.
* Fixed. Old code had slightly different problem here:
* extra fput() in situation when we passed the descriptor via
* such socket and closed it (descriptor). That would happen on
* each unix_gc() until the accept(). Since the struct file in
* question would go to the free list and might be reused...
* That might be the reason of random oopses on filp_close()
* in unrelated processes.
*
* AV 28 Feb 1999
* Kill the explicit allocation of stack. Now we keep the tree
* with root in dummy + pointer (gc_current) to one of the nodes.
* Stack is represented as path from gc_current to dummy. Unmark
* now means "add to tree". Push == "make it a son of gc_current".
* Pop == "move gc_current to parent". We keep only pointers to
* parents (->gc_tree).
* AV 1 Mar 1999
* Damn. Added missing check for ->dead in listen queues scanning.
*
*/
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/un.h>
#include <linux/net.h>
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <linux/file.h>
#include <linux/proc_fs.h>
#include <linux/mutex.h>
#include <net/sock.h>
#include <net/af_unix.h>
#include <net/scm.h>
#include <net/tcp_states.h>
/* Internal data structures and random procedures: */
#define GC_HEAD ((struct sock *)(-1))
#define GC_ORPHAN ((struct sock *)(-3))
static struct sock *gc_current = GC_HEAD; /* stack of objects to mark */
atomic_t unix_tot_inflight = ATOMIC_INIT(0);
static struct sock *unix_get_socket(struct file *filp)
{
struct sock *u_sock = NULL;
struct inode *inode = filp->f_path.dentry->d_inode;
/*
* Socket ?
*/
if (S_ISSOCK(inode->i_mode)) {
struct socket * sock = SOCKET_I(inode);
struct sock * s = sock->sk;
/*
* PF_UNIX ?
*/
if (s && sock->ops && sock->ops->family == PF_UNIX)
u_sock = s;
}
return u_sock;
}
/*
* Keep the number of times in flight count for the file
* descriptor if it is for an AF_UNIX socket.
*/
void unix_inflight(struct file *fp)
{
struct sock *s = unix_get_socket(fp);
if(s) {
atomic_inc(&unix_sk(s)->inflight);
atomic_inc(&unix_tot_inflight);
}
}
void unix_notinflight(struct file *fp)
{
struct sock *s = unix_get_socket(fp);
if(s) {
atomic_dec(&unix_sk(s)->inflight);
atomic_dec(&unix_tot_inflight);
}
}
/*
* Garbage Collector Support Functions
*/
static inline struct sock *pop_stack(void)
{
struct sock *p = gc_current;
gc_current = unix_sk(p)->gc_tree;
return p;
}
static inline int empty_stack(void)
{
return gc_current == GC_HEAD;
}
static void maybe_unmark_and_push(struct sock *x)
{
struct unix_sock *u = unix_sk(x);
if (u->gc_tree != GC_ORPHAN)
return;
sock_hold(x);
u->gc_tree = gc_current;
gc_current = x;
}
/* The external entry point: unix_gc() */
void unix_gc(void)
{
static DEFINE_MUTEX(unix_gc_sem);
int i;
struct sock *s;
struct sk_buff_head hitlist;
struct sk_buff *skb;
/*
* Avoid a recursive GC.
*/
if (!mutex_trylock(&unix_gc_sem))
return;
spin_lock(&unix_table_lock);
forall_unix_sockets(i, s)
{
unix_sk(s)->gc_tree = GC_ORPHAN;
}
/*
* Everything is now marked
*/
/* Invariant to be maintained:
- everything unmarked is either:
-- (a) on the stack, or
-- (b) has all of its children unmarked
- everything on the stack is always unmarked
- nothing is ever pushed onto the stack twice, because:
-- nothing previously unmarked is ever pushed on the stack
*/
/*
* Push root set
*/
forall_unix_sockets(i, s)
{
int open_count = 0;
/*
* If all instances of the descriptor are not
* in flight we are in use.
*
* Special case: when socket s is embrion, it may be
* hashed but still not in queue of listening socket.
* In this case (see unix_create1()) we set artificial
* negative inflight counter to close race window.
* It is trick of course and dirty one.
*/
if (s->sk_socket && s->sk_socket->file)
open_count = file_count(s->sk_socket->file);
if (open_count > atomic_read(&unix_sk(s)->inflight))
maybe_unmark_and_push(s);
}
/*
* Mark phase
*/
while (!empty_stack())
{
struct sock *x = pop_stack();
struct sock *sk;
spin_lock(&x->sk_receive_queue.lock);
skb = skb_peek(&x->sk_receive_queue);
/*
* Loop through all but first born
*/
while (skb && skb != (struct sk_buff *)&x->sk_receive_queue) {
/*
* Do we have file descriptors ?
*/
if(UNIXCB(skb).fp)
{
/*
* Process the descriptors of this socket
*/
int nfd=UNIXCB(skb).fp->count;
struct file **fp = UNIXCB(skb).fp->fp;
while(nfd--)
{
/*
* Get the socket the fd matches if
* it indeed does so
*/
if((sk=unix_get_socket(*fp++))!=NULL)
{
maybe_unmark_and_push(sk);
}
}
}
/* We have to scan not-yet-accepted ones too */
if (x->sk_state == TCP_LISTEN)
maybe_unmark_and_push(skb->sk);
skb=skb->next;
}
spin_unlock(&x->sk_receive_queue.lock);
sock_put(x);
}
skb_queue_head_init(&hitlist);
forall_unix_sockets(i, s)
{
struct unix_sock *u = unix_sk(s);
if (u->gc_tree == GC_ORPHAN) {
struct sk_buff *nextsk;
spin_lock(&s->sk_receive_queue.lock);
skb = skb_peek(&s->sk_receive_queue);
while (skb &&
skb != (struct sk_buff *)&s->sk_receive_queue) {
nextsk = skb->next;
/*
* Do we have file descriptors ?
*/
if (UNIXCB(skb).fp) {
__skb_unlink(skb,
&s->sk_receive_queue);
__skb_queue_tail(&hitlist, skb);
}
skb = nextsk;
}
spin_unlock(&s->sk_receive_queue.lock);
}
u->gc_tree = GC_ORPHAN;
}
spin_unlock(&unix_table_lock);
/*
* Here we are. Hitlist is filled. Die.
*/
__skb_queue_purge(&hitlist);
mutex_unlock(&unix_gc_sem);
}