Re: [PATCH] p54: avoid accessing the data mapped to streaming DMA
From: Kalle Valo <hidden>
Date: 2020-08-18 12:42:23
Also in:
lkml, netdev
From: Kalle Valo <hidden>
Date: 2020-08-18 12:42:23
Also in:
lkml, netdev
Jia-Ju Bai [off-list ref] wrote:
In p54p_tx(), skb->data is mapped to streaming DMA on line 337: mapping = pci_map_single(..., skb->data, ...); Then skb->data is accessed on line 349: desc->device_addr = ((struct p54_hdr *)skb->data)->req_id; This access may cause data inconsistency between CPU cache and hardware. To fix this problem, ((struct p54_hdr *)skb->data)->req_id is stored in a local variable before DMA mapping, and then the driver accesses this local variable instead of skb->data. Signed-off-by: Jia-Ju Bai <redacted>
Can someone review this? -- https://patchwork.kernel.org/patch/11696391/ https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches