[PATCH v2] uapi/fcntl: define RENAME_* and AT_RENAME_* macros

[Randy Dunlap <rdunlap@infradead.org>]

Define the RENAME_* and AT_RENAME_* macros exactly the same as in
recent glibc <stdio.h> so that duplicate definition build errors in
both samples/watch_queue/watch_test.c and samples/vfs/test-statx.c
no longer happen. When they defined in exactly the same way in
multiple places, the build errors are prevented.

Defining only the AT_RENAME_* macros is not sufficient since they
depend on the RENAME_* macros, which may not be defined when the
AT_RENAME_* macros are used.

Build errors being fixed:

for samples/vfs/test-statx.c:

In file included from ../samples/vfs/test-statx.c:23:
usr/include/linux/fcntl.h:159:9: warning: ‘AT_RENAME_NOREPLACE’ redefined
  159 | #define AT_RENAME_NOREPLACE     0x0001
In file included from ../samples/vfs/test-statx.c:13:
/usr/include/stdio.h:171:10: note: this is the location of the previous definition
  171 | # define AT_RENAME_NOREPLACE RENAME_NOREPLACE
usr/include/linux/fcntl.h:160:9: warning: ‘AT_RENAME_EXCHANGE’ redefined
  160 | #define AT_RENAME_EXCHANGE      0x0002
/usr/include/stdio.h:173:10: note: this is the location of the previous definition
  173 | # define AT_RENAME_EXCHANGE RENAME_EXCHANGE
usr/include/linux/fcntl.h:161:9: warning: ‘AT_RENAME_WHITEOUT’ redefined
  161 | #define AT_RENAME_WHITEOUT      0x0004
/usr/include/stdio.h:175:10: note: this is the location of the previous definition
  175 | # define AT_RENAME_WHITEOUT RENAME_WHITEOUT

for samples/watch_queue/watch_test.c:

In file included from usr/include/linux/watch_queue.h:6,
                 from ../samples/watch_queue/watch_test.c:19:
usr/include/linux/fcntl.h:159:9: warning: ‘AT_RENAME_NOREPLACE’ redefined
  159 | #define AT_RENAME_NOREPLACE     0x0001
In file included from ../samples/watch_queue/watch_test.c:11:
/usr/include/stdio.h:171:10: note: this is the location of the previous definition
  171 | # define AT_RENAME_NOREPLACE RENAME_NOREPLACE
usr/include/linux/fcntl.h:160:9: warning: ‘AT_RENAME_EXCHANGE’ redefined
  160 | #define AT_RENAME_EXCHANGE      0x0002
/usr/include/stdio.h:173:10: note: this is the location of the previous definition
  173 | # define AT_RENAME_EXCHANGE RENAME_EXCHANGE
usr/include/linux/fcntl.h:161:9: warning: ‘AT_RENAME_WHITEOUT’ redefined
  161 | #define AT_RENAME_WHITEOUT      0x0004
/usr/include/stdio.h:175:10: note: this is the location of the previous definition
  175 | # define AT_RENAME_WHITEOUT RENAME_WHITEOUT

Fixes: b4fef22c2fb9 ("uapi: explain how per-syscall AT_* flags should be allocated")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
---
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Jeff Layton <jlayton@kernel.org>
Cc: Chuck Lever <chuck.lever@oracle.com>
Cc: Alexander Aring <alex.aring@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Aleksa Sarai <cyphar@cyphar.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Howells <dhowells@redhat.com>
CC: linux-api@vger.kernel.org
To: linux-fsdevel@vger.kernel.org

 include/uapi/linux/fcntl.h |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

--- linux-next-20250819.orig/include/uapi/linux/fcntl.h
+++ linux-next-20250819/include/uapi/linux/fcntl.h
@@ -156,9 +156,12 @@
  */
 
 /* Flags for renameat2(2) (must match legacy RENAME_* flags). */
-#define AT_RENAME_NOREPLACE	0x0001
-#define AT_RENAME_EXCHANGE	0x0002
-#define AT_RENAME_WHITEOUT	0x0004
+# define RENAME_NOREPLACE (1 << 0)
+# define AT_RENAME_NOREPLACE RENAME_NOREPLACE
+# define RENAME_EXCHANGE (1 << 1)
+# define AT_RENAME_EXCHANGE RENAME_EXCHANGE
+# define RENAME_WHITEOUT (1 << 2)
+# define AT_RENAME_WHITEOUT RENAME_WHITEOUT
 
 /* Flag for faccessat(2). */
 #define AT_EACCESS		0x200	/* Test access permitted for