[PATCH] wcn36xx: add proper DMA memory barriers in rx path

[Kalle Valo]

Benjamin Li <benl at squareup.com> wrote:

> This is essentially exactly following the dma_wmb()/dma_rmb() usage
> instructions in Documentation/memory-barriers.txt.
> 
> The theoretical races here are:
> 
> 1. DXE (the DMA Transfer Engine in the Wi-Fi subsystem) seeing the
> dxe->ctrl & WCN36xx_DXE_CTRL_VLD write before the dxe->dst_addr_l
> write, thus performing DMA into the wrong address.
> 
> 2. CPU reading dxe->dst_addr_l before DXE unsets dxe->ctrl &
> WCN36xx_DXE_CTRL_VLD. This should generally be harmless since DXE
> doesn't write dxe->dst_addr_l (no risk of freeing the wrong skb).
> 
> Fixes: 8e84c2582169 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
> Signed-off-by: Benjamin Li <benl at squareup.com>
> Signed-off-by: Kalle Valo <kvalo at codeaurora.org>

Patch applied to ath-next branch of ath.git, thanks.

9bfe38e064af wcn36xx: add proper DMA memory barriers in rx path

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20211023001528.3077822-1-benl@squareup.com/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches