Commit a75d9797 authored by Pavel Emelyanov's avatar Pavel Emelyanov Committed by Linus Torvalds
Browse files

bsdacct: turn the acct_lock from on-the-struct to global 



Don't use per-bsd-acct-struct lock, but work with a global one.

This lock is taken for short periods, so it doesn't seem it'll become a
bottleneck, but it will allow us to easily avoid many locking difficulties
in the future.

So this is a mostly s/acct_globals.lock/acct_lock/ over the file.

Signed-off-by: default avatarPavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e59a04a7

kernel/acct.c

+21 −21
Original line number Diff line number Diff line
@@ -83,7 +83,6 @@ static void do_acct_process(struct pid_namespace *ns, struct file *); 
 * the cache line to have the data after getting the lock.

 */

struct bsd_acct_struct {

	spinlock_t		lock;

	volatile int		active;

	volatile int		needcheck;

	struct file		*file;
@@ -91,8 +90,9 @@ struct bsd_acct_struct { 
	struct timer_list	timer;

};



static struct bsd_acct_struct acct_globals __cacheline_aligned =

	{__SPIN_LOCK_UNLOCKED(acct_globals.lock)};

static DEFINE_SPINLOCK(acct_lock);



static struct bsd_acct_struct acct_globals __cacheline_aligned;



/*

 * Called whenever the timer says to check the free space.
@@ -114,11 +114,11 @@ static int check_free_space(struct file *file) 
	sector_t resume;

	sector_t suspend;



	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	res = acct_globals.active;

	if (!file || !acct_globals.needcheck)

		goto out;

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);



	/* May block */

	if (vfs_statfs(file->f_path.dentry, &sbuf))
@@ -140,7 +140,7 @@ static int check_free_space(struct file *file) 
	 * If some joker switched acct_globals.file under us we'ld better be

	 * silent and _not_ touch anything.

	 */

	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	if (file != acct_globals.file) {

		if (act)

			res = act>0;
@@ -165,7 +165,7 @@ static int check_free_space(struct file *file) 
	add_timer(&acct_globals.timer);

	res = acct_globals.active;

out:

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);

	return res;

}
@@ -173,7 +173,7 @@ out: 
 * Close the old accounting file (if currently open) and then replace

 * it with file (if non-NULL).

 *

 * NOTE: acct_globals.lock MUST be held on entry and exit.

 * NOTE: acct_lock MUST be held on entry and exit.

 */

static void acct_file_reopen(struct file *file)

{
@@ -201,11 +201,11 @@ static void acct_file_reopen(struct file *file) 
	}

	if (old_acct) {

		mnt_unpin(old_acct->f_path.mnt);

		spin_unlock(&acct_globals.lock);

		spin_unlock(&acct_lock);

		do_acct_process(old_ns, old_acct);

		filp_close(old_acct, NULL);

		put_pid_ns(old_ns);

		spin_lock(&acct_globals.lock);

		spin_lock(&acct_lock);

	}

}
@@ -235,10 +235,10 @@ static int acct_on(char *name) 
		return error;

	}



	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	mnt_pin(file->f_path.mnt);

	acct_file_reopen(file);

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);



	mntput(file->f_path.mnt); /* it's pinned, now give up active reference */
@@ -272,9 +272,9 @@ asmlinkage long sys_acct(const char __user *name) 
	} else {

		error = security_acct(NULL);

		if (!error) {

			spin_lock(&acct_globals.lock);

			spin_lock(&acct_lock);

			acct_file_reopen(NULL);

			spin_unlock(&acct_globals.lock);

			spin_unlock(&acct_lock);

		}

	}

	return error;
@@ -289,10 +289,10 @@ asmlinkage long sys_acct(const char __user *name) 
 */

void acct_auto_close_mnt(struct vfsmount *m)

{

	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	if (acct_globals.file && acct_globals.file->f_path.mnt == m)

		acct_file_reopen(NULL);

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);

}



/**
@@ -304,12 +304,12 @@ void acct_auto_close_mnt(struct vfsmount *m) 
 */

void acct_auto_close(struct super_block *sb)

{

	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	if (acct_globals.file &&

	    acct_globals.file->f_path.mnt->mnt_sb == sb) {

		acct_file_reopen(NULL);

	}

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);

}



/*
@@ -594,15 +594,15 @@ void acct_process(void) 
	if (!acct_globals.file)

		return;



	spin_lock(&acct_globals.lock);

	spin_lock(&acct_lock);

	file = acct_globals.file;

	if (unlikely(!file)) {

		spin_unlock(&acct_globals.lock);

		spin_unlock(&acct_lock);

		return;

	}

	get_file(file);

	ns = get_pid_ns(acct_globals.ns);

	spin_unlock(&acct_globals.lock);

	spin_unlock(&acct_lock);



	do_acct_process(ns, file);

	fput(file);

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