UbiquitousOS
/
OpenCloudOS-Kernel
mirror of https://gitee.com/OpenCloudOS/OpenCloudOS-Kernel.git
11
0
Fork 0
Code Issues Projects Releases Wiki Activity

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>
This commit is contained in:
Daniel Mack 2018-04-10 19:35:58 +02:00 committed by Kalle Valo
parent 6da2b2d46f
commit 9ff6fde86f
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/net/wireless/ath/wcn36xx/dxe.c
View File

@ -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);