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Subject[PATCH 30/32] staging: wfx: fix potential deadlock in wfx_tx_flush()
Date
From: Jérôme Pouiller <jerome.pouiller@silabs.com>

wfx_tx_flush() wait there are no more frame in device buffer. However,
this event may never happens since wfx_tx_flush() don't forbid to
enqueue new frames.

Note that wfx_tx_flush() should only ensure that all frames currently in
hardware queues are sent. So the current code is more restrictive that
it should.

Note that wfx_tx_flush() release the lock before to return while
wfx_tx_lock_flush() keep the lock.

Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
---
drivers/staging/wfx/queue.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/staging/wfx/queue.c b/drivers/staging/wfx/queue.c
index d4302a30dc41..e6d7d0e45156 100644
--- a/drivers/staging/wfx/queue.c
+++ b/drivers/staging/wfx/queue.c
@@ -36,6 +36,7 @@ void wfx_tx_flush(struct wfx_dev *wdev)
if (wdev->chip_frozen)
return;

+ wfx_tx_lock(wdev);
mutex_lock(&wdev->hif_cmd.lock);
ret = wait_event_timeout(wdev->hif.tx_buffers_empty,
!wdev->hif.tx_buffers_used,
@@ -54,6 +55,7 @@ void wfx_tx_flush(struct wfx_dev *wdev)
wdev->chip_frozen = 1;
}
mutex_unlock(&wdev->hif_cmd.lock);
+ wfx_tx_unlock(wdev);
}

void wfx_tx_lock_flush(struct wfx_dev *wdev)
--
2.25.1
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