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authorMateusz Guzik <mjguzik@gmail.com>2025-03-19 13:49:23 +0100
committerChristian Brauner <brauner@kernel.org>2025-03-19 14:09:58 +0100
commit9ae7e5a1cd17b271e1b3339a23883d3d64724dcc (patch)
tree54065ce766278bb21114f5786e2c2a8b1b72cf55
parent5a607aa94398760585579649f0881d2d354f4e00 (diff)
fs: predict not reaching the limit in alloc_empty_file()
Eliminates a jump over a call to capable() in the common case. By default the limit is not even set, in which case the check can't even fail to begin with. It remains unset at least on Debian and Ubuntu. For this cases this can probably become a static branch instead. In the meantime tidy it up. I note the check separate from the bump makes the entire thing racy. Signed-off-by: Mateusz Guzik <mjguzik@gmail.com> Link: https://lore.kernel.org/r/20250319124923.1838719-1-mjguzik@gmail.com Signed-off-by: Christian Brauner <brauner@kernel.org>
-rw-r--r--fs/file_table.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/file_table.c b/fs/file_table.c
index f0291a66f9db..4d9f723350fb 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -216,7 +216,8 @@ struct file *alloc_empty_file(int flags, const struct cred *cred)
/*
* Privileged users can go above max_files
*/
- if (get_nr_files() >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) {
+ if (unlikely(get_nr_files() >= files_stat.max_files) &&
+ !capable(CAP_SYS_ADMIN)) {
/*
* percpu_counters are inaccurate. Do an expensive check before
* we go and fail.