Thread (7 messages) 7 messages, 3 authors, 2020-09-01

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

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
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