[PATCH] wifi: mt76: mt7996: remove redundant NULL check in mt7996_msdu_page_get_from_cache()

[PATCH] wifi: mt76: mt7996: remove redundant NULL check in mt7996_msdu_page_get_from_cache()

[Rakuram Eswaran]

Smatch reported a warning that the NULL check on `p` in
`mt7996_msdu_page_get_from_cache()` is redundant:

  drivers/net/wireless/mediatek/mt76/mt7996/mac.c:1651
  mt7996_msdu_page_get_from_cache() warn: can 'p' even be NULL?

The function first checks `list_empty(&dev->wed_rro.page_cache)` before
calling `list_first_entry()`. When the list is not empty,
`list_first_entry()` always returns a valid pointer and can never be NULL.

Hence, the `if (p)` condition is unnecessary. Removing it cleans up the
code.

Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/202510100155.MS0IXhzm-lkp@intel.com/
Signed-off-by: Rakuram Eswaran <rakuram.e96@gmail.com>
---
 drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index 9501def3e0e3e20132fdbcfe0b1f489694afdc5f..284f2eea71e5bf0a34c7fe84084d998164a31a05 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -1681,8 +1681,7 @@ mt7996_msdu_page_get_from_cache(struct mt7996_dev *dev)
 	if (!list_empty(&dev->wed_rro.page_cache)) {
 		p = list_first_entry(&dev->wed_rro.page_cache,
 				     struct mt7996_msdu_page, list);
-		if (p)
-			list_del(&p->list);
+		list_del(&p->list);
 	}
 
 	spin_unlock(&dev->wed_rro.lock);

---
base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada
change-id: 20251022-mt7996_mac_c-e10894b8bbb4

Best regards,
-- 
Rakuram Eswaran <rakuram.e96@gmail.com>

Re: [PATCH] wifi: mt76: mt7996: remove redundant NULL check in mt7996_msdu_page_get_from_cache()

[Lorenzo Bianconi]

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> Smatch reported a warning that the NULL check on `p` in
> `mt7996_msdu_page_get_from_cache()` is redundant:
> 
>   drivers/net/wireless/mediatek/mt76/mt7996/mac.c:1651
>   mt7996_msdu_page_get_from_cache() warn: can 'p' even be NULL?
> 
> The function first checks `list_empty(&dev->wed_rro.page_cache)` before
> calling `list_first_entry()`. When the list is not empty,
> `list_first_entry()` always returns a valid pointer and can never be NULL.
> 
> Hence, the `if (p)` condition is unnecessary. Removing it cleans up the
> code.

Hi Rakuram,

this issue has been already fixed here:
https://patchwork.kernel.org/project/linux-wireless/patch/20251014-mt7996_msdu_page_get_from_cache-remove-null-ptr-check-v1-1-fbeb7881e192@kernel.org/

Regards,
Lorenzo

> 
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202510100155.MS0IXhzm-lkp@intel.com/
> Signed-off-by: Rakuram Eswaran <rakuram.e96@gmail.com>
> ---
>  drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> index 9501def3e0e3e20132fdbcfe0b1f489694afdc5f..284f2eea71e5bf0a34c7fe84084d998164a31a05 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
> @@ -1681,8 +1681,7 @@ mt7996_msdu_page_get_from_cache(struct mt7996_dev *dev)
>  	if (!list_empty(&dev->wed_rro.page_cache)) {
>  		p = list_first_entry(&dev->wed_rro.page_cache,
>  				     struct mt7996_msdu_page, list);
> -		if (p)
> -			list_del(&p->list);
> +		list_del(&p->list);
>  	}
>  
>  	spin_unlock(&dev->wed_rro.lock);
> 
> ---
> base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada
> change-id: 20251022-mt7996_mac_c-e10894b8bbb4
> 
> Best regards,
> -- 
> Rakuram Eswaran <rakuram.e96@gmail.com>
> 

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Re: [PATCH] wifi: mt76: mt7996: remove redundant NULL check in mt7996_msdu_page_get_from_cache()

[Rakuram Eswaran]

On Thu, 23 Oct 2025 at 18:45, Lorenzo Bianconi <lorenzo@kernel.org> wrote:
>
> > Smatch reported a warning that the NULL check on `p` in
> > `mt7996_msdu_page_get_from_cache()` is redundant:
> >
> >   drivers/net/wireless/mediatek/mt76/mt7996/mac.c:1651
> >   mt7996_msdu_page_get_from_cache() warn: can 'p' even be NULL?
> >
> > The function first checks `list_empty(&dev->wed_rro.page_cache)` before
> > calling `list_first_entry()`. When the list is not empty,
> > `list_first_entry()` always returns a valid pointer and can never be NULL.
> >
> > Hence, the `if (p)` condition is unnecessary. Removing it cleans up the
> > code.
>
> Hi Rakuram,
>
> this issue has been already fixed here:
> https://patchwork.kernel.org/project/linux-wireless/patch/20251014-mt7996_msdu_page_get_from_cache-remove-null-ptr-check-v1-1-fbeb7881e192@kernel.org/
>
> Regards,
> Lorenzo
>

Hello Lorenzo,

Thank you for the information. I did check both linus-mainline and linux-next
branches before sending the patch. 

From next time, I’ll make sure to also check the subsystem-specific branches as well.

Thanks again for pointing it out.

Best regards,
Rakuram