[PATCH] Reinit the RX DMA buffer to avoid skb conflict， Handle all RX packets in the DMA ring buffer

[Kalle Valo]

YanBo <dreamfly281 at gmail.com> writes:

> This patch is used to reallocation the rx skb buffer instead of clone
> it, cause if just clone the skb, the hardware may refill the skb
> buffer when the upper layer still ir. and this skb buffer is still in
> DMA mapping status, it should not be access by the CPU before unmap
> it.
>
> Another function of this patch is it will check every possible filled
> RX descriptor in the ring buffer and handle them at once, normally the
> hardware may fill more than one RX descriptors but just trigger one
> interrupt to reduce CPU interrupt load.
>
> (This patch is just for pre review cause it is just generated after
> rebased on the newest wcn36xx repo. I have tested it in the previous
> wcn36xx repo.  but still not verify it after rebase due to lack of
> time, welcome to get you feedback for this)

The patch was severily whitspace damaged so it was pretty difficult to
review. I recommend using git send-email to submit patches, it usually
gets everything right.

I need to review this again, but I found one issue now:

> +static int wcn36xx_dxe_fill_skb(struct wcn36xx_dxe_ctl *cur_dxe_ctl)
> +{
> + struct wcn36xx_dxe_desc *cur_dxe_desc = cur_dxe_ctl->desc;
> + struct sk_buff *skb;
> +
> + skb = alloc_skb(WCN36XX_PKT_SIZE, GFP_ATOMIC);
> +        if (skb == NULL) {
> + wcn36xx_error("DMA buffer allocation failed");
> + return -1;

This needs to be -ENOMEM or similar. Also there's a general rule in
Linux that memory allocation failures don't need any error messages, the
memory subsystem handles that.

-- 
Kalle Valo