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

From: Arnd Bergmann <arnd@kernel.org>
To: linux-kernel@vger.kernel.org, Xiubo Li <xiubli@redhat.com>,
	Ilya Dryomov <idryomov@gmail.com>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Nathan Chancellor <nathan@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>, Jeff Layton <jlayton@kernel.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Milind Changire <mchangir@redhat.com>,
	Patrick Donnelly <pdonnell@redhat.com>,
	Christian Brauner <brauner@kernel.org>,
	ceph-devel@vger.kernel.org, netdev@vger.kernel.org,
	llvm@lists.linux.dev
Subject: [PATCH 2/9] libceph: avoid clang out-of-range warning
Date: Thu, 28 Mar 2024 15:30:40 +0100	[thread overview]
Message-ID: <20240328143051.1069575-3-arnd@kernel.org> (raw)
In-Reply-To: <20240328143051.1069575-1-arnd@kernel.org>

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

