2021-10-29 15:44:07

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] iwlwifi: pcie: fix constant-conversion warning

From: Arnd Bergmann <[email protected]>

clang points out a potential issue with integer overflow when
the iwl_dev_info_table[] array is empty:

drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~

This is still harmless, as the loop correctly terminates, but adding
an (int) cast makes that clearer to the compiler.

Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/wireless/intel/iwlwifi/pcie/drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
index c574f041f096..81e8f2fc4982 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
@@ -1341,7 +1341,7 @@ iwl_pci_find_dev_info(u16 device, u16 subsystem_device,
{
int i;

- for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
+ for (i = (int)ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
const struct iwl_dev_info *dev_info = &iwl_dev_info_table[i];

if (dev_info->device != (u16)IWL_CFG_ANY &&
--
2.29.2


2021-10-31 07:31:26

by Kalle Valo

[permalink] [raw]
Subject: Re: [PATCH] iwlwifi: pcie: fix constant-conversion warning

Arnd Bergmann <[email protected]> writes:

> From: Arnd Bergmann <[email protected]>
>
> clang points out a potential issue with integer overflow when
> the iwl_dev_info_table[] array is empty:
>
> drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
> for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
> ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
>
> This is still harmless, as the loop correctly terminates, but adding
> an (int) cast makes that clearer to the compiler.
>
> Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
> Signed-off-by: Arnd Bergmann <[email protected]>

Luca, can I take this to wireless-drivers? Ack?

--
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

2021-11-01 07:30:05

by Luciano Coelho

[permalink] [raw]
Subject: Re: [PATCH] iwlwifi: pcie: fix constant-conversion warning

On Sun, 2021-10-31 at 09:06 +0200, Kalle Valo wrote:
> Arnd Bergmann <[email protected]> writes:
>
> > From: Arnd Bergmann <[email protected]>
> >
> > clang points out a potential issue with integer overflow when
> > the iwl_dev_info_table[] array is empty:
> >
> > drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
> > for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
> > ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
> >
> > This is still harmless, as the loop correctly terminates, but adding
> > an (int) cast makes that clearer to the compiler.
> >
> > Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
> > Signed-off-by: Arnd Bergmann <[email protected]>
>
> Luca, can I take this to wireless-drivers? Ack?

Yes, please do.

Thanks.

Acked-by: Luca Coelho <[email protected]>

--
Cheers,
Luca.

2021-11-01 07:32:28

by Luciano Coelho

[permalink] [raw]
Subject: Re: [PATCH] iwlwifi: pcie: fix constant-conversion warning

On Mon, 2021-11-01 at 09:29 +0200, Luciano Coelho wrote:
> On Sun, 2021-10-31 at 09:06 +0200, Kalle Valo wrote:
> > Arnd Bergmann <[email protected]> writes:
> >
> > > From: Arnd Bergmann <[email protected]>
> > >
> > > clang points out a potential issue with integer overflow when
> > > the iwl_dev_info_table[] array is empty:
> > >
> > > drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1344:42: error: implicit conversion from 'unsigned long' to 'int' changes value from 18446744073709551615 to -1 [-Werror,-Wconstant-conversion]
> > > for (i = ARRAY_SIZE(iwl_dev_info_table) - 1; i >= 0; i--) {
> > > ~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
> > >
> > > This is still harmless, as the loop correctly terminates, but adding
> > > an (int) cast makes that clearer to the compiler.
> > >
> > > Fixes: 3f7320428fa4 ("iwlwifi: pcie: simplify iwl_pci_find_dev_info()")
> > > Signed-off-by: Arnd Bergmann <[email protected]>
> >
> > Luca, can I take this to wireless-drivers? Ack?
>
> Yes, please do.
>
> Thanks.
>
> Acked-by: Luca Coelho <[email protected]>

Actually, wouldn't it be simpler to change the declaration of i to be
unsigned int?

--
Luca.