From fe116788393942eef11d5c0f1cb16b1ef423970d Mon Sep 17 00:00:00 2001 From: Brian Norris Date: Fri, 13 Jan 2017 15:35:38 -0800 Subject: [PATCH] mwifiex: pcie: read FROMDEVICE DMA-able memory with READ_ONCE() 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 Signed-off-by: Kalle Valo --- drivers/net/wireless/marvell/mwifiex/pcie.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/marvell/mwifiex/pcie.c b/drivers/net/wireless/marvell/mwifiex/pcie.c index b8a07d35973a..ca51411e4a4c 100644 --- a/drivers/net/wireless/marvell/mwifiex/pcie.c +++ b/drivers/net/wireless/marvell/mwifiex/pcie.c @@ -442,7 +442,7 @@ 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, -- 2.20.1