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fs: Use try_cmpxchg() in sb_init_done_wq() 

Use !try_cmpxchg() instead of cmpxchg(*ptr, old, new) != old.

The x86 CMPXCHG instruction returns success in the ZF flag,
so this change saves a compare after CMPXCHG.

No functional change intended.

Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/20250811132326.620521-1-ubizjak@gmail.com
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Uros Bizjak 2025-08-11 15:23:03 +02:00 committed by Christian Brauner
parent 14498ca7e0
commit ec6f613ef3
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1 changed files with 5 additions and 3 deletions
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6
fs/super.c
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@ -2318,13 +2318,15 @@ int sb_init_dio_done_wq(struct super_block *sb)
sb->s_id);
if (!wq)
return -ENOMEM;
old = NULL;
/*
* This has to be atomic as more DIOs can race to create the workqueue
*/
old = cmpxchg(&sb->s_dio_done_wq, NULL, wq);
if (!try_cmpxchg(&sb->s_dio_done_wq, &old, wq)) {
/* Someone created workqueue before us? Free ours... */
if (old)
destroy_workqueue(wq);
}
return 0;
}
EXPORT_SYMBOL_GPL(sb_init_dio_done_wq);