[PATCH 2/9] libceph: avoid clang out-of-range warning

Arnd Bergmann
2024-03-28T14:31:29Z

From: Arnd Bergmann <arnd@arndb.de>

clang-14 points out that on 64-bit architectures, a u32
is never larger than constant based on SIZE_MAX:

net/ceph/osdmap.c:1425:10: error: result of comparison of constant 4611686018427387891 with expression of type 'u32' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
net/ceph/osdmap.c:1608:10: error: result of comparison of constant 2305843009213693945 with expression of type 'u32' (aka 'unsigned int') is always false [-Werror,-Wtautological-constant-out-of-range-compare]
if (len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32)))
~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The code is correct anyway, so just shut up that warning.

Fixes: 6f428df47dae ("libceph: pg_upmap[_items] infrastructure")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
fs/ceph/snap.c | 2 +-
net/ceph/osdmap.c | 4 ++--
2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c
index c65f2b202b2b..521507ea8260 100644
--- a/fs/ceph/snap.c
+++ b/fs/ceph/snap.c
@@ -374,7 +374,7 @@ static int build_snap_context(struct ceph_mds_client *mdsc,

/* alloc new snap context */
err = -ENOMEM;
- if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
+ if ((size_t)num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))
goto fail;
snapc = ceph_create_snap_context(num, GFP_NOFS);
if (!snapc)
diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c
index 295098873861..8e7cb2fde6f1 100644
--- a/net/ceph/osdmap.c
+++ b/net/ceph/osdmap.c
@@ -1438,7 +1438,7 @@ static struct ceph_pg_mapping *__decode_pg_temp(void **p, void *end,
ceph_decode_32_safe(p, end, len, e_inval);
if (len == 0 && incremental)
return NULL; /* new_pg_temp: [] to remove */
- if (len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
+ if ((size_t)len > (SIZE_MAX - sizeof(*pg)) / sizeof(u32))
return ERR_PTR(-EINVAL);

ceph_decode_need(p, end, len * sizeof(u32), e_inval);
@@ -1621,7 +1621,7 @@ static struct ceph_pg_mapping *__decode_pg_upmap_items(void **p, void *end,
u32 len, i;

ceph_decode_32_safe(p, end, len, e_inval);
- if (len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32)))
+ if ((size_t)len > (SIZE_MAX - sizeof(*pg)) / (2 * sizeof(u32)))
return ERR_PTR(-EINVAL);

ceph_decode_need(p, end, 2 * len * sizeof(u32), e_inval);
--
2.39.2