2022-08-24 08:32:46

by CGEL

Subject: [PATCH] staging: r8188eu: remove unnecessary null check

From: Minghao Chi <[email protected]>

container_of is never null, so this null check is
unnecessary.

Reported-by: Zeal Robot <[email protected]>
Signed-off-by: Minghao Chi <[email protected]>
---
drivers/staging/r8188eu/core/rtw_mlme.c | 4 ----
1 file changed, 4 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_mlme.c b/drivers/staging/r8188eu/core/rtw_mlme.c
index 56c8bd5f4c60..d089da7e90e0 100644
--- a/drivers/staging/r8188eu/core/rtw_mlme.c
+++ b/drivers/staging/r8188eu/core/rtw_mlme.c
@@ -1442,10 +1442,6 @@ int rtw_select_and_join_from_scanned_queue(struct mlme_priv *pmlmepriv)
pmlmepriv->pscanned = phead->next;
while (phead != pmlmepriv->pscanned) {
pnetwork = container_of(pmlmepriv->pscanned, struct wlan_network, list);
- if (!pnetwork) {
- ret = _FAIL;
- goto exit;
- }
pmlmepriv->pscanned = pmlmepriv->pscanned->next;
rtw_check_join_candidate(pmlmepriv, &candidate, pnetwork);
}
--
2.25.1

2022-08-25 07:23:13

by Dan Carpenter

Subject: Re: [PATCH] staging: r8188eu: remove unnecessary null check

On Wed, Aug 24, 2022 at 08:03:50AM +0000, [email protected] wrote:
> From: Minghao Chi <[email protected]>
>
> container_of is never null, so this null check is
> unnecessary.
>

I can't Ack a patch with this commit message because container_of()
*CAN* be NULL. Here, it requires two things:
1) That ->list is the first struct member of struct wlan_network which
is true.
2) That "pmlmepriv->pscanned" is NULL. Which I have not looked at.

It's really ugly to check container_of() for NULL but some people do it
deliberately. Some people also will add a build time assert to ensure
that ->list is always the first element so that the check always works.

regards,
dan carpenter