platform: sps: Fix an unsigned comparison that can never be negative

[PATCH v2] platform: sps: Fix an unsigned comparison that can never be negative

Posted by coolrrsh@gmail.com 2 years, 4 months ago

From: Rajeshwar R Shinde <coolrrsh@gmail.com>

The variable 'mode' is declared as unsigned int in local function.
The return value of function amd_pmf_get_pprof_modes(dev) is int and
it is stored in the 'mode' variable. Also the value of 'mode' variable
is compared with 0 which is signed int by default. Thus redeclaring the
variable to signed int.

This fixes warning such as:
drivers/platform/x86/amd/pmf/sps.c:128:5-9:
WARNING: Unsigned expression compared with zero: mode < 0

Signed-off-by: Rajeshwar R Shinde <coolrrsh@gmail.com>

---
v1->v2
changed the commit subject
---
 drivers/platform/x86/amd/pmf/sps.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/platform/x86/amd/pmf/sps.c b/drivers/platform/x86/amd/pmf/sps.c
index ab69d517a36a..703723a66830 100644
--- a/drivers/platform/x86/amd/pmf/sps.c
+++ b/drivers/platform/x86/amd/pmf/sps.c
@@ -176,7 +176,7 @@ int amd_pmf_get_pprof_modes(struct amd_pmf_dev *pmf)
 
 int amd_pmf_power_slider_update_event(struct amd_pmf_dev *dev)
 {
-	u8 mode, flag = 0;
+	int mode, flag = 0;
 	int src;
 
 	mode = amd_pmf_get_pprof_modes(dev);
-- 
2.25.1

Re: [PATCH v2] platform: sps: Fix an unsigned comparison that can never be negative

Posted by Hans de Goede 2 years, 4 months ago

Hi,

On 8/13/23 13:08, coolrrsh@gmail.com wrote:
> From: Rajeshwar R Shinde <coolrrsh@gmail.com>
> 
> The variable 'mode' is declared as unsigned int in local function.
> The return value of function amd_pmf_get_pprof_modes(dev) is int and
> it is stored in the 'mode' variable. Also the value of 'mode' variable
> is compared with 0 which is signed int by default. Thus redeclaring the
> variable to signed int.
> 
> This fixes warning such as:
> drivers/platform/x86/amd/pmf/sps.c:128:5-9:
> WARNING: Unsigned expression compared with zero: mode < 0
> 
> Signed-off-by: Rajeshwar R Shinde <coolrrsh@gmail.com>

Thank you your patch.

This has already been fixed by a patch which is pending in the pdx86/fixes branch:

https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/commit/?h=fixes&id=785c00993dc4c4bb2f7b0f3a3f29c03a6f7aab2e
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=fixes

Regards,

Hans