On Wed 19-03-25 13:49:23, Mateusz Guzik wrote:
> 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@xxxxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> fs/file_table.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/file_table.c b/fs/file_table.c
> index 5b4cc9da1344..c04ed94cdc4b 100644
> --- a/fs/file_table.c
> +++ b/fs/file_table.c
> @@ -221,7 +221,8 @@ 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.
> --
> 2.43.0
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
