diff mbox

[v2,3/3] mwifiex: pcie: read FROMDEVICE DMA-able memory with READ_ONCE()

Message ID 20170113233538.36196-3-briannorris@chromium.org (mailing list archive)
State Accepted
Commit fe116788393942eef11d5c0f1cb16b1ef423970d
Delegated to: Kalle Valo
Headers show

Commit Message

Brian Norris Jan. 13, 2017, 11:35 p.m. UTC
In mwifiex_delay_for_sleep_cookie(), we're looping and waiting for the
PCIe endpoint to write a magic value back to memory, to signal that it
has finished going to sleep. We're not letting the compiler know that
this might change underneath our feet though. Let's do that, for good
hygiene.

I'm not aware of this fixing any concrete problems. I also give no
guarantee that this loop is actually correct in any other way, but at
least this looks like an improvement to me.

Signed-off-by: Brian Norris <briannorris@chromium.org>
---
v2: new in v2
---
 drivers/net/wireless/marvell/mwifiex/pcie.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c
index 194e0e04c3b1..c2511f212502 100644
--- a/drivers/net/wireless/marvell/mwifiex/pcie.c
+++ b/drivers/net/wireless/marvell/mwifiex/pcie.c
@@ -440,7 +440,7 @@  static void mwifiex_delay_for_sleep_cookie(struct mwifiex_adapter *adapter,
 
 	for (count = 0; count < max_delay_loop_cnt; count++) {
 		buffer = card->cmdrsp_buf->data - INTF_HEADER_LEN;
-		sleep_cookie = *(u32 *)buffer;
+		sleep_cookie = READ_ONCE(*(u32 *)buffer);
 
 		if (sleep_cookie == MWIFIEX_DEF_SLEEP_COOKIE) {
 			mwifiex_dbg(adapter, INFO,