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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 <briannorris@chromium.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
This commit is contained in:
Brian Norris 2017-01-13 15:35:38 -08:00 committed by Kalle Valo
parent 5d5ddb5e0d
commit fe11678839
1 changed files with 1 additions and 1 deletions
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2
drivers/net/wireless/marvell/mwifiex/pcie.c
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@ -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,