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[PATCH] free_uid() locking improvement 

Reduce lock hold times in free_uid().

Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Andrew Morton 2006-03-24 03:15:47 -08:00 committed by Linus Torvalds
parent 3cf64b933c
commit 36f574135e
1 changed files with 7 additions and 3 deletions
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10
kernel/user.c
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@ -105,15 +105,19 @@ void free_uid(struct user_struct *up)
{ {
unsigned long flags; unsigned long flags;
if (!up)
return;
local_irq_save(flags); local_irq_save(flags);
if (up && atomic_dec_and_lock(&up->__count, &uidhash_lock)) { if (atomic_dec_and_lock(&up->__count, &uidhash_lock)) {
uid_hash_remove(up); uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
key_put(up->uid_keyring); key_put(up->uid_keyring);
key_put(up->session_keyring); key_put(up->session_keyring);
kmem_cache_free(uid_cachep, up); kmem_cache_free(uid_cachep, up);
spin_unlock(&uidhash_lock); } else {
local_irq_restore(flags);
} }
local_irq_restore(flags);
} }
struct user_struct * alloc_uid(uid_t uid) struct user_struct * alloc_uid(uid_t uid)