[PATCH 6.18 293/641] jfs: avoid -Wtautological-constant-out-of-range-compare warning

Greg Kroah-Hartman
2026-02-25T06:55:53Z

6.18-stable review patch. If anyone has any objections, please let me know.

------------------

From: Arnd Bergmann <arnd@arndb.de>

[ Upstream commit 7833570dae833028337bb53b7f389825b910c100 ]

A recent change for the range check started triggering a clang warning:

fs/jfs/jfs_dtree.c:2906:31: error: result of comparison of constant 128 with expression of type 's8' (aka 'signed char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
2906 | if (stbl[i] < 0 || stbl[i] >= DTPAGEMAXSLOT) {
| ~~~~~~~ ^ ~~~~~~~~~~~~~
fs/jfs/jfs_dtree.c:3111:30: error: result of comparison of constant 128 with expression of type 's8' (aka 'signed char') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
3111 | if (stbl[0] < 0 || stbl[0] >= DTPAGEMAXSLOT) {
| ~~~~~~~ ^ ~~~~~~~~~~~~~

Both the old and the new check were useless, but the previous version
apparently did not lead to the warning.

Remove the extraneous range check for simplicity.

Fixes: cafc6679824a ("jfs: replace hardcoded magic number with DTPAGEMAXSLOT constant")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/jfs/jfs_dtree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/jfs/jfs_dtree.c b/fs/jfs/jfs_dtree.c
index 0ab83bb7bbdf9..9ab3f2fc61d17 100644
--- a/fs/jfs/jfs_dtree.c
+++ b/fs/jfs/jfs_dtree.c
@@ -2903,7 +2903,7 @@ int jfs_readdir(struct file *file, struct dir_context *ctx)
stbl = DT_GETSTBL(p);

for (i = index; i < p->header.nextindex; i++) {
- if (stbl[i] < 0 || stbl[i] >= DTPAGEMAXSLOT) {
+ if (stbl[i] < 0) {
jfs_err("JFS: Invalid stbl[%d] = %d for inode %ld, block = %lld",
i, stbl[i], (long)ip->i_ino, (long long)bn);
free_page(dirent_buf);
@@ -3108,7 +3108,7 @@ static int dtReadFirst(struct inode *ip, struct btstack * btstack)
/* get the leftmost entry */
stbl = DT_GETSTBL(p);

- if (stbl[0] < 0 || stbl[0] >= DTPAGEMAXSLOT) {
+ if (stbl[0] < 0) {
DT_PUTPAGE(mp);
jfs_error(ip->i_sb, "stbl[0] out of bound\n");
return -EIO;
--
2.51.0