2023-10-26 09:18:30

by Su Hui

Subject: [PATCH v2] vga_switcheroo: Fix impossible judgment condition

'id' is enum type like unsigned int, so it will never be less than zero.
It's better to check VGA_SWITCHEROO_UNKNOWN_ID too.

Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
Signed-off-by: Su Hui <[email protected]>
---
v2:
- add check of VGA_SWITCHEROO_UNKNOWN_ID(Dan's suggestion).

By the way, all functions of 'get_client_id' will never return error code
or VGA_SWITCHEROO_UNKNOWN_ID，should we remove this check or keep it for
future.

drivers/gpu/vga/vga_switcheroo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/vga/vga_switcheroo.c b/drivers/gpu/vga/vga_switcheroo.c
index 365e6ddbe90f..cf530094f929 100644
--- a/drivers/gpu/vga/vga_switcheroo.c
+++ b/drivers/gpu/vga/vga_switcheroo.c
@@ -375,7 +375,7 @@ int vga_switcheroo_register_audio_client(struct pci_dev *pdev,
mutex_lock(&vgasr_mutex);
if (vgasr_priv.active) {
id = vgasr_priv.handler->get_client_id(vga_dev);
- if (id < 0) {
+ if ((int)id < 0 || id == VGA_SWITCHEROO_UNKNOWN_ID) {
mutex_unlock(&vgasr_mutex);
return -EINVAL;
}
--
2.30.2

2023-10-26 09:31:13

by Dan Carpenter

Subject: Re: [PATCH v2] vga_switcheroo: Fix impossible judgment condition

On Thu, Oct 26, 2023 at 05:18:04PM +0800, Su Hui wrote:
> 'id' is enum type like unsigned int, so it will never be less than zero.
> It's better to check VGA_SWITCHEROO_UNKNOWN_ID too.
>
> Fixes: 4aaf448fa975 ("vga_switcheroo: set audio client id according to bound GPU id")
> Signed-off-by: Su Hui <[email protected]>
> ---
> v2:
> - add check of VGA_SWITCHEROO_UNKNOWN_ID(Dan's suggestion).
>
> By the way, all functions of 'get_client_id' will never return error code
> or VGA_SWITCHEROO_UNKNOWN_ID，should we remove this check or keep it for
> future.
>

Thanks!

Reviewed-by: Dan Carpenter <[email protected]>

regards,
dan carpenter