address remaining -Wtautological-constant-out-of-range-compare

[PATCH 1/9] dm integrity: fix out-of-range warning

Posted by Arnd Bergmann 1 year, 10 months ago

From: Arnd Bergmann <arnd@arndb.de>

Depending on the value of CONFIG_HZ, clang compares about a pointless
comparison:

drivers/md/dm-integrity.c:4085:12: error: result of comparison of constant 42949672950 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
                        if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {

As the check remains useful for other configurations, shut up the
warning by adding a second type cast to uint64_t.

Fixes: 468dfca38b1a ("dm integrity: add a bitmap mode")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/md/dm-integrity.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
index 37b9f8f1ae1a..7f3dc8ee6ab8 100644
--- a/drivers/md/dm-integrity.c
+++ b/drivers/md/dm-integrity.c
@@ -4221,7 +4221,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
 		} else if (sscanf(opt_string, "sectors_per_bit:%llu%c", &llval, &dummy) == 1) {
 			log2_sectors_per_bitmap_bit = !llval ? 0 : __ilog2_u64(llval);
 		} else if (sscanf(opt_string, "bitmap_flush_interval:%u%c", &val, &dummy) == 1) {
-			if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
+			if ((uint64_t)val >= (uint64_t)UINT_MAX * 1000 / HZ) {
 				r = -EINVAL;
 				ti->error = "Invalid bitmap_flush_interval argument";
 				goto bad;
-- 
2.39.2

Re: [PATCH 1/9] dm integrity: fix out-of-range warning

Posted by Justin Stitt 1 year, 10 months ago

On Thu, Mar 28, 2024 at 7:31 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> Depending on the value of CONFIG_HZ, clang compares about a pointless
> comparison:
>
> drivers/md/dm-integrity.c:4085:12: error: result of comparison of constant 42949672950 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
>                         if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
>
> As the check remains useful for other configurations, shut up the
> warning by adding a second type cast to uint64_t.

Yeah, nice.

>
> Fixes: 468dfca38b1a ("dm integrity: add a bitmap mode")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Justin Stitt <justinstitt@google.com>

> ---
>  drivers/md/dm-integrity.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
> index 37b9f8f1ae1a..7f3dc8ee6ab8 100644
> --- a/drivers/md/dm-integrity.c
> +++ b/drivers/md/dm-integrity.c
> @@ -4221,7 +4221,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
>                 } else if (sscanf(opt_string, "sectors_per_bit:%llu%c", &llval, &dummy) == 1) {
>                         log2_sectors_per_bitmap_bit = !llval ? 0 : __ilog2_u64(llval);
>                 } else if (sscanf(opt_string, "bitmap_flush_interval:%u%c", &val, &dummy) == 1) {
> -                       if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
> +                       if ((uint64_t)val >= (uint64_t)UINT_MAX * 1000 / HZ) {
>                                 r = -EINVAL;
>                                 ti->error = "Invalid bitmap_flush_interval argument";
>                                 goto bad;
> --
> 2.39.2
>

Re: [PATCH 1/9] dm integrity: fix out-of-range warning

Posted by Mikulas Patocka 1 year, 10 months ago


On Thu, 28 Mar 2024, Arnd Bergmann wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> Depending on the value of CONFIG_HZ, clang compares about a pointless
> comparison:
> 
> drivers/md/dm-integrity.c:4085:12: error: result of comparison of constant 42949672950 with expression of type 'unsigned int' is always false [-Werror,-Wtautological-constant-out-of-range-compare]
>                         if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
> 
> As the check remains useful for other configurations, shut up the
> warning by adding a second type cast to uint64_t.
> 
> Fixes: 468dfca38b1a ("dm integrity: add a bitmap mode")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>

> ---
>  drivers/md/dm-integrity.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/md/dm-integrity.c b/drivers/md/dm-integrity.c
> index 37b9f8f1ae1a..7f3dc8ee6ab8 100644
> --- a/drivers/md/dm-integrity.c
> +++ b/drivers/md/dm-integrity.c
> @@ -4221,7 +4221,7 @@ static int dm_integrity_ctr(struct dm_target *ti, unsigned int argc, char **argv
>  		} else if (sscanf(opt_string, "sectors_per_bit:%llu%c", &llval, &dummy) == 1) {
>  			log2_sectors_per_bitmap_bit = !llval ? 0 : __ilog2_u64(llval);
>  		} else if (sscanf(opt_string, "bitmap_flush_interval:%u%c", &val, &dummy) == 1) {
> -			if (val >= (uint64_t)UINT_MAX * 1000 / HZ) {
> +			if ((uint64_t)val >= (uint64_t)UINT_MAX * 1000 / HZ) {
>  				r = -EINVAL;
>  				ti->error = "Invalid bitmap_flush_interval argument";
>  				goto bad;
> -- 
> 2.39.2
>