Instead to having macro definition for millisecond timeout have
the definition directly in jiffies. This makes the unit of the
value immediately clear and may result in code that is bit more
compact.
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
brcmf_msgbuf_ioctl_resp_wake() seems to be missing a memory barrier
which might cause the waker to not notice the waiter and miss sending a
wake_up as in the following figure.
brcmf_msgbuf_ioctl_resp_wake brcmf_msgbuf_ioctl_resp_wait
------------------------------------------------------------------------
if (waitqueue_active(&msgbuf->ioctl_resp_wait))
/* The CPU might reorder the test for
the waitqueue up here, before
prior writes complete */
/* wait_event_timeout */
/* __wait_event_timeout */
/* ___wait_event */
prepare_to_wait_event(&wq, &__wait,
state);
if (msgbuf->ctl_completed)
...
msgbuf->ctl_completed = true;
schedule_timeout(__ret))
------------------------------------------------------------------------
There are three other place in drivers/net/wireless/brcm80211/brcmfmac/
which have similar code. The attached patch removes the call to
waitqueue_active() leaving just wake_up() behind. This fixes the
problem because the call to spin_lock_irqsave() in wake_up() will be an
ACQUIRE operation.
I found this issue when I was looking through the linux source code
for places calling waitqueue_active() before wake_up*(), but without
preceding memory barriers, after sending a patch to fix a similar
issue in drivers/tty/n_tty.c (Details about the original issue can be
found here: https://lkml.org/lkml/2015/9/28/849).
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Reviewed-by: Franky (Zhenhui) Lin <frankyl@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Kosuke Tatsukawa <tatsu@ab.jp.nec.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Part of reorganising wireless drivers directory and Kconfig. Note that I had to
edit Makefiles from subdirectories to use the new location.
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
