linux-kernel - [RFC PATCH v3 04/59] do_utimes_path(): import pathname only once

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Message-ID: <20251216035518.4037331-5-viro@zeniv.linux.org.uk>
Date: Tue, 16 Dec 2025 03:54:23 +0000
From: Al Viro <viro@...iv.linux.org.uk>
To: linux-fsdevel@...r.kernel.org
Cc: torvalds@...ux-foundation.org,
	brauner@...nel.org,
	jack@...e.cz,
	mjguzik@...il.com,
	paul@...l-moore.com,
	axboe@...nel.dk,
	audit@...r.kernel.org,
	io-uring@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [RFC PATCH v3 04/59] do_utimes_path(): import pathname only once

Convert the user_path_at() call inside a retry loop into getname_flags() +
filename_lookup() + putname() and leave only filename_lookup() inside
the loop.

Since we have the default logics for use of LOOKUP_EMPTY (passed iff
AT_EMPTY_PATH is present in flags), just use getname_uflags() and
don't bother with setting LOOKUP_EMPTY in lookup_flags - getname_uflags()
will pass the right thing to getname_flags() and filename_lookup()
doesn't care about LOOKUP_EMPTY at all.

The things could be further simplified by use of cleanup.h stuff, but
let's not clutter the patch with that.

Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
 fs/utimes.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/utimes.c b/fs/utimes.c
index 86f8ce8cd6b1..84889ea1780e 100644
--- a/fs/utimes.c
+++ b/fs/utimes.c
@@ -8,6 +8,7 @@
 #include <linux/compat.h>
 #include <asm/unistd.h>
 #include <linux/filelock.h>
+#include "internal.h"
 
 static bool nsec_valid(long nsec)
 {
@@ -83,27 +84,27 @@ static int do_utimes_path(int dfd, const char __user *filename,
 {
 	struct path path;
 	int lookup_flags = 0, error;
+	struct filename *name;
 
 	if (flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
 		return -EINVAL;
 
 	if (!(flags & AT_SYMLINK_NOFOLLOW))
 		lookup_flags |= LOOKUP_FOLLOW;
-	if (flags & AT_EMPTY_PATH)
-		lookup_flags |= LOOKUP_EMPTY;
+	name = getname_uflags(filename, flags);
 
 retry:
-	error = user_path_at(dfd, filename, lookup_flags, &path);
+	error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
 	if (error)
-		return error;
-
+		goto out;
 	error = vfs_utimes(&path, times);
 	path_put(&path);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
-
+out:
+	putname(name);
 	return error;
 }
 
-- 
2.47.3