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

Lorenzo Bianconi
2025-10-23T13:16:07Z

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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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