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[30/32] staging: wfx: fix potential deadlock in wfx_tx_flush()

Message ID 20200401110405.80282-31-Jerome.Pouiller@silabs.com
State New
Headers show
Series [01/32] staging: wfx: add sanity checks to hif_join() | expand

Commit Message

Jérôme Pouiller April 1, 2020, 11:04 a.m. UTC 
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(+)
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Patch

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)