From: Uros Bizjak <ubizjak@gmail.com>
To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Uros Bizjak <ubizjak@gmail.com>,
Alexander Viro <viro@zeniv.linux.org.uk>
Subject: [PATCH] posix_acl: Use try_cmpxchg in get_acl
Date: Thu, 14 Jul 2022 19:38:19 +0200 [thread overview]
Message-ID: <20220714173819.13312-1-ubizjak@gmail.com> (raw)
Use try_cmpxchg instead of cmpxchg (*ptr, old, new) == old
in get_acl. x86 CMPXCHG instruction returns success in ZF flag,
so this change saves a compare after cmpxchg (and related move
instruction in front of cmpxchg).
No functional change intended.
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
---
fs/posix_acl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/posix_acl.c b/fs/posix_acl.c
index 962d32468eb4..49a13fd4d3cb 100644
--- a/fs/posix_acl.c
+++ b/fs/posix_acl.c
@@ -164,7 +164,7 @@ struct posix_acl *get_acl(struct inode *inode, int type)
* Cache the result, but only if our sentinel is still in place.
*/
posix_acl_dup(acl);
- if (unlikely(cmpxchg(p, sentinel, acl) != sentinel))
+ if (unlikely(!try_cmpxchg(p, &sentinel, acl)))
posix_acl_release(acl);
return acl;
}
--
2.35.3
next reply other threads:[~2022-07-14 17:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-14 17:38 Uros Bizjak [this message]
[not found] <202207162205.iBwToBEr-lkp@intel.com>
2022-07-18 2:05 ` [PATCH] posix_acl: Use try_cmpxchg in get_acl kernel test robot
2022-12-21 19:35 Uros Bizjak
2022-12-23 10:47 ` Christian Brauner
2023-01-08 11:42 ` Christian Brauner
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