From: Pavel Emelyanov Date: Fri, 25 Jul 2008 08:48:45 +0000 (-0700) Subject: bsdacct: turn the acct_lock from on-the-struct to global X-Git-Tag: v2.6.27-rc1~259 X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=a75d97976517dcda69150fd81d6be86ae63324a1;p=linux-2.6-omap-h63xx.git 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: Pavel Emelyanov Cc: Balbir Singh Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/kernel/acct.c b/kernel/acct.c index 05f8bc094a4..fc71c130497 100644 --- a/kernel/acct.c +++ b/kernel/acct.c @@ -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);