[PATCH 6/10] Bsdacct: make the acct_lock global

Pavel Emelyanov
2008-04-10T08:48:13Z

Don't use per-bsd-acct-struct lock, but work with a global
one. This lock is taken for short periods, so it's not going
to be a bottleneck, but it will allow us to easily avoid
many locking difficulties in the future.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>

---
kernel/acct.c | 42 +++++++++++++++++++++---------------------
1 files changed, 21 insertions(+), 21 deletions(-)

diff --git a/kernel/acct.c b/kernel/acct.c
index 05f8bc0..fc71c13 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);
--
1.5.3.4