From: Mateusz Guzik <mjguzik@gmail.com>
To: brauner@kernel.org
Cc: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
jack@suse.cz, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, Mateusz Guzik <mjguzik@gmail.com>
Subject: [PATCH 1/2] fs: touch up predicts in inode_permission()
Date: Thu, 17 Apr 2025 00:16:25 +0200 [thread overview]
Message-ID: <20250416221626.2710239-2-mjguzik@gmail.com> (raw)
In-Reply-To: <20250416221626.2710239-1-mjguzik@gmail.com>
The routine only encounters errors when people try to access things they
can't, which is a negligible amount of calls.
The only questionable bit might be the pre-existing predict around
MAY_WRITE. Currently the routine is predominantly used for MAY_EXEC, so
this makes some sense.
I verified this straightens out the asm.
Signed-off-by: Mateusz Guzik <mjguzik@gmail.com>
---
fs/namei.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c
index daebc307c1a3..cff69c12d6fd 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -571,14 +571,14 @@ int inode_permission(struct mnt_idmap *idmap,
int retval;
retval = sb_permission(inode->i_sb, inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
if (unlikely(mask & MAY_WRITE)) {
/*
* Nobody gets write access to an immutable file.
*/
- if (IS_IMMUTABLE(inode))
+ if (unlikely(IS_IMMUTABLE(inode)))
return -EPERM;
/*
@@ -586,16 +586,16 @@ int inode_permission(struct mnt_idmap *idmap,
* written back improperly if their true value is unknown
* to the vfs.
*/
- if (HAS_UNMAPPED_ID(idmap, inode))
+ if (unlikely(HAS_UNMAPPED_ID(idmap, inode)))
return -EACCES;
}
retval = do_inode_permission(idmap, inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
retval = devcgroup_inode_permission(inode, mask);
- if (retval)
+ if (unlikely(retval))
return retval;
return security_inode_permission(inode, mask);
--
2.48.1
next prev parent reply other threads:[~2025-04-16 22:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-04-16 22:16 [PATCH 0/2] two nits for path lookup Mateusz Guzik
2025-04-16 22:16 ` Mateusz Guzik [this message]
2025-04-16 22:16 ` [PATCH 2/2] device_cgroup: avoid access to ->i_rdev in the common case in devcgroup_inode_permission() Mateusz Guzik
2025-04-16 22:35 ` [PATCH 0/2] two nits for path lookup Mateusz Guzik
2025-04-16 22:39 ` Linus Torvalds
2025-04-17 8:13 ` Christian Brauner
2025-04-17 9:04 ` Christian Brauner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20250416221626.2710239-2-mjguzik@gmail.com \
--to=mjguzik@gmail.com \
--cc=brauner@kernel.org \
--cc=jack@suse.cz \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=torvalds@linux-foundation.org \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®