Re: [PATCH v4] brcm80211: fmac: Add error log in brcmf_usb_dl_cmd()

[Arend Van Spriel <arend.vanspriel@broadcom.com>]

On April 15, 2025 2:21:37 PM Wentao Liang <vulab@iscas.ac.cn> wrote:

> In brcmf_usb_dl_cmd(), the error logging is not enough to describe
> the error state. And some caller of the brcmf_usb_dl_cmd() does not
> handle its error. An error log in brcmf_usb_dl_cmd() is needed to
> prevent silent failure.
>
> Add error handling in brcmf_usb_dl_cmd() to log the command id and
> error code in the brcmf_usb_dl_cmd() fails. In this way, every
> invocation of the function logs a message upon failure.
>
> Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
> ---
> v4: Fix spelling problem.
> v3: Change patch name and comment. Move error log into brcmf_usb_dl_cmd().
> v2: Remove redundant bailing out code.
>
> .../wireless/broadcom/brcm80211/brcmfmac/usb.c   | 16 ++++++++++++----
> 1 file changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c 
> b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
> index d06c724f63d9..a11a6d9f3c2b 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
> @@ -744,12 +744,16 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info 
> *devinfo, u8 cmd,
> char *tmpbuf;
> u16 size;
>
> - if ((!devinfo) || (devinfo->ctl_urb == NULL))
> - return -EINVAL;
> + if (!devinfo || !devinfo->ctl_urb) {
> + ret = -EINVAL;
> + goto err;
> + }
>
> tmpbuf = kmalloc(buflen, GFP_ATOMIC);
> - if (!tmpbuf)
> - return -ENOMEM;
> + if (!tmpbuf) {
> + ret = -ENOMEM;
> + goto err;
> + }
>
> size = buflen;
> devinfo->ctl_urb->transfer_buffer_length = size;
> @@ -783,6 +787,10 @@ static int brcmf_usb_dl_cmd(struct brcmf_usbdev_info 
> *devinfo, u8 cmd,
> finalize:

The finalize label is used for failure path as well. So I suggest to get 
rid of it requiring modified patch like:

- finalize:
        kfree(tmpbuf);
-       return ret;
+.     return 0;
+
+ err:

+      brcmf_err("dl cmd %u failed: err=%d\n", cmd, ret);
+      kfree(tmpbuf);
+      return ret;
}

Obviously this means tmpbuf should be NULL initialized.

Regards,
Arend