[PATCH 4/7] namei: clean up do_mknodat retry logic

[Dmitry Kadashev <dkadashev@xxxxxxxxx>]

Moving the main logic to a helper function makes the whole thing much
easier to follow.

Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christian Brauner <christian.brauner@xxxxxxxxxx>
Suggested-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/io-uring/CAHk-=wiG+sN+2zSoAOggKCGue2kOJvw3rQySvQXsZstRQFTN+g@xxxxxxxxxxxxxx/
Signed-off-by: Dmitry Kadashev <dkadashev@xxxxxxxxx>
---
 fs/namei.c | 31 ++++++++++++++++++-------------
 1 file changed, 18 insertions(+), 13 deletions(-)

diff --git a/fs/namei.c b/fs/namei.c
index b9762e2cf3b9..7bf7a9f38ce2 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -3745,29 +3745,27 @@ static int may_mknod(umode_t mode)
 	}
 }
 
-static int do_mknodat(int dfd, struct filename *name, umode_t mode,
-		unsigned int dev)
+static int mknodat_helper(int dfd, struct filename *name, umode_t mode,
+			  unsigned int dev, unsigned int lookup_flags)
 {
 	struct user_namespace *mnt_userns;
 	struct dentry *dentry;
 	struct path path;
 	int error;
-	unsigned int lookup_flags = 0;
 
 	error = may_mknod(mode);
 	if (error)
-		goto out1;
-retry:
+		return error;
 	dentry = __filename_create(dfd, name, &path, lookup_flags);
 	error = PTR_ERR(dentry);
 	if (IS_ERR(dentry))
-		goto out1;
+		return error;
 
 	if (!IS_POSIXACL(path.dentry->d_inode))
 		mode &= ~current_umask();
 	error = security_path_mknod(&path, dentry, mode, dev);
 	if (error)
-		goto out2;
+		goto out;
 
 	mnt_userns = mnt_user_ns(path.mnt);
 	switch (mode & S_IFMT) {
@@ -3786,13 +3784,20 @@ static int do_mknodat(int dfd, struct filename *name, umode_t mode,
 					  dentry, mode, 0);
 			break;
 	}
-out2:
+out:
 	done_path_create(&path, dentry);
-	if (retry_estale(error, lookup_flags)) {
-		lookup_flags |= LOOKUP_REVAL;
-		goto retry;
-	}
-out1:
+	return error;
+}
+
+static int do_mknodat(int dfd, struct filename *name, umode_t mode,
+		unsigned int dev)
+{
+	int error;
+
+	error = mknodat_helper(dfd, name, mode, dev, 0);
+	if (retry_estale(error, 0))
+		error = mknodat_helper(dfd, name, mode, dev, LOOKUP_REVAL);
+
 	putname(name);
 	return error;
 }
-- 
2.30.2