| Message ID | 20220707173040.704116-1-justinstitt@google.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net: ipv4: fix clang -Wformat warning | expand |
On Thu, 2022-07-07 at 10:30 -0700, Justin Stitt wrote: > 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. I think it also makes sense to use %u and not %d as the original type is unsigned. > diff --git 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);
On Thu, Jul 7, 2022 at 10:40 AM Joe Perches <joe@perches.com> wrote: > > On Thu, 2022-07-07 at 10:30 -0700, Justin Stitt wrote: > > 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. > > I think it also makes sense to use %u and not %d > as the original type is unsigned. Yeah, that would also work. An integer (even a signed one) fully encompasses a u16 so it's really a choice of style. Do you think the change to %u warrants a v2 of this patch? > > > diff --git 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); >
On Thu, 2022-07-07 at 10:47 -0700, Justin Stitt wrote: > On Thu, Jul 7, 2022 at 10:40 AM Joe Perches <joe@perches.com> wrote: > > > > On Thu, 2022-07-07 at 10:30 -0700, Justin Stitt wrote: > > > 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. > > > > I think it also makes sense to use %u and not %d > > as the original type is unsigned. > Yeah, that would also work. An integer (even a signed one) fully > encompasses a u16 so it's really a choice of style. Do you think the > change to %u warrants a v2 of this patch? As it's rather odd output to use '%u != %d', probably. Your patch, up to you. > > > > > diff --git 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); > >
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);
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@google.com> --- net/ipv4/ah4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)