linux-kernel - [RFC PATCH v3 09/59] do_readlinkat(): import pathname only once

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Message-ID: <20251216035518.4037331-10-viro@zeniv.linux.org.uk>
Date: Tue, 16 Dec 2025 03:54:28 +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 09/59] do_readlinkat(): import pathname only once

Take getname_flags() and putname() outside of retry loop.

Since getname_flags() is the only thing that cares about LOOKUP_EMPTY,
don't bother with setting LOOKUP_EMPTY in lookup_flags - just pass it
to getname_flags() and be done with that.

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/stat.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/stat.c b/fs/stat.c
index 6c79661e1b96..ee9ae2c3273a 100644
--- a/fs/stat.c
+++ b/fs/stat.c
@@ -566,13 +566,13 @@ static int do_readlinkat(int dfd, const char __user *pathname,
 	struct path path;
 	struct filename *name;
 	int error;
-	unsigned int lookup_flags = LOOKUP_EMPTY;
+	unsigned int lookup_flags = 0;
 
 	if (bufsiz <= 0)
 		return -EINVAL;
 
+	name = getname_flags(pathname, LOOKUP_EMPTY);
 retry:
-	name = getname_flags(pathname, lookup_flags);
 	error = filename_lookup(dfd, name, lookup_flags, &path, NULL);
 	if (unlikely(error)) {
 		putname(name);
@@ -593,11 +593,11 @@ static int do_readlinkat(int dfd, const char __user *pathname,
 		error = (name->name[0] == '\0') ? -ENOENT : -EINVAL;
 	}
 	path_put(&path);
-	putname(name);
 	if (retry_estale(error, lookup_flags)) {
 		lookup_flags |= LOOKUP_REVAL;
 		goto retry;
 	}
+	putname(name);
 	return error;
 }
 
-- 
2.47.3