[PATCH] net: ipv4: fix clang -Wformat warning

From: Justin Stitt
Date: Thu Jul 07 2022 - 13:32:35 EST


When building with Clang we encounter this warning:
| net/ipv4/ah4.c:513:4: error: format specifies type 'unsigned short' but
| the argument has type 'int' [-Werror,-Wformat]
| aalg_desc->uinfo.auth.icv_fullbits / 8);

`aalg_desc->uinfo.auth.icv_fullbits` is a u16 but due to default
argument promotion becomes an int.

Variadic functions (printf-like) undergo default argument promotion.
Documentation/core-api/printk-formats.rst specifically recommends using
the promoted-to-type's format flag.

As per C11 6.3.1.1:
(https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf) `If an int
can represent all values of the original type ..., the value is
converted to an int; otherwise, it is converted to an unsigned int.
These are called the integer promotions.` Thus it makes sense to change
%hu to %d not only to follow this standard but to suppress the warning
as well.

Link: https://github.com/ClangBuiltLinux/linux/issues/378
Signed-off-by: Justin Stitt <justinstitt@xxxxxxxxxx>
---
net/ipv4/ah4.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/ah4.c b/net/ipv4/ah4.c
index 6eea1e9e998d..3bf3d01fb7e3 100644
--- a/net/ipv4/ah4.c
+++ b/net/ipv4/ah4.c
@@ -507,7 +507,7 @@ static int ah_init_state(struct xfrm_state *x)

if (aalg_desc->uinfo.auth.icv_fullbits/8 !=
crypto_ahash_digestsize(ahash)) {
- pr_info("%s: %s digestsize %u != %hu\n",
+ pr_info("%s: %s digestsize %u != %d\n",
__func__, x->aalg->alg_name,
crypto_ahash_digestsize(ahash),
aalg_desc->uinfo.auth.icv_fullbits / 8);
--
2.37.0.rc0.161.g10f37bed90-goog