diff options
| author | Daniel Mack <daniel@zonque.org> | 2018-04-10 20:35:58 +0300 |
|---|---|---|
| committer | Kalle Valo <kvalo@codeaurora.org> | 2018-04-19 19:22:43 +0300 |
| commit | 9ff6fde86fd27a0c733c01114eb0d46bd3a33fb7 (patch) | |
| tree | aa54bac9457e49aabcb6bb0928eb7fbb85e1ca0e | |
| parent | 6da2b2d46ff937edc3ecea0a36d92252981d033a (diff) | |
| download | linux-9ff6fde86fd27a0c733c01114eb0d46bd3a33fb7.tar.xz | |
wcn36xx: use READ_ONCE() to access desc->ctrl
When accessing shared memory to check for the stat of submitted
descriptors, make sure to use READ_ONCE(). This will guarantee the
compiler treats these memory locations as volatile and doesn't apply
any caching.
While this doesn't fix any particular problem I ran into, it's best
practice to do it this way.
Note that this patch also removes the superflous extra condition check
in the do-while loop in reap_tx_dxes(), as the loop will break
instantly anyway in that case.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
| -rw-r--r-- | drivers/net/wireless/ath/wcn36xx/dxe.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/net/wireless/ath/wcn36xx/dxe.c b/drivers/net/wireless/ath/wcn36xx/dxe.c index a6702ada13d3..bd2b946a65c9 100644 --- a/drivers/net/wireless/ath/wcn36xx/dxe.c +++ b/drivers/net/wireless/ath/wcn36xx/dxe.c @@ -368,7 +368,7 @@ static void reap_tx_dxes(struct wcn36xx *wcn, struct wcn36xx_dxe_ch *ch) spin_lock_irqsave(&ch->lock, flags); ctl = ch->tail_blk_ctl; do { - if (ctl->desc->ctrl & WCN36xx_DXE_CTRL_VLD) + if (READ_ONCE(ctl->desc->ctrl) & WCN36xx_DXE_CTRL_VLD) break; if (ctl->skb) { dma_unmap_single(wcn->dev, ctl->desc->src_addr_l, @@ -387,8 +387,7 @@ static void reap_tx_dxes(struct wcn36xx *wcn, struct wcn36xx_dxe_ch *ch) ctl->skb = NULL; } ctl = ctl->next; - } while (ctl != ch->head_blk_ctl && - !(ctl->desc->ctrl & WCN36xx_DXE_CTRL_VLD)); + } while (ctl != ch->head_blk_ctl); ch->tail_blk_ctl = ctl; spin_unlock_irqrestore(&ch->lock, flags); @@ -530,7 +529,7 @@ static int wcn36xx_rx_handle_packets(struct wcn36xx *wcn, int_mask = WCN36XX_DXE_INT_CH3_MASK; } - while (!(dxe->ctrl & WCN36xx_DXE_CTRL_VLD)) { + while (!(READ_ONCE(dxe->ctrl) & WCN36xx_DXE_CTRL_VLD)) { skb = ctl->skb; dma_addr = dxe->dst_addr_l; ret = wcn36xx_dxe_fill_skb(wcn->dev, ctl, GFP_ATOMIC); |