[PATCH v3 04/13] ASoC: SDCA: Correct FDL locking in sdca_fdl_process()

[Charles Keepax <ckeepax@opensource.cirrus.com>]

The current locking in sdca_fdl_process() locks over
sdca_ump_cancel_timeout() and the timeout work function takes the same
lock, this can lead to a deadlock if the work runs as part of the
cancel. To fix this move the guard() call to below the cancel timeout,
putting it outside the lock.

Fixes: e92e25f77748 ("ASoC: SDCA: Add UMP timeout handling for FDL")
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v2:
 - Switched back to guard() and just moved it down a little.

 sound/soc/sdca/sdca_fdl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/soc/sdca/sdca_fdl.c b/sound/soc/sdca/sdca_fdl.c
index cb79dc3131b82..bc88d24d63d7f 100644
--- a/sound/soc/sdca/sdca_fdl.c
+++ b/sound/soc/sdca/sdca_fdl.c
@@ -402,8 +402,6 @@ int sdca_fdl_process(struct sdca_interrupt *interrupt)
 	unsigned int reg, status;
 	int response, ret;
 
-	guard(mutex)(&fdl_state->lock);
-
 	ret = sdca_ump_get_owner_host(dev, interrupt->function_regmap,
 				      interrupt->function, interrupt->entity,
 				      interrupt->control);
@@ -412,6 +410,8 @@ int sdca_fdl_process(struct sdca_interrupt *interrupt)
 
 	sdca_ump_cancel_timeout(&fdl_state->timeout);
 
+	guard(mutex)(&fdl_state->lock);
+
 	reg = SDW_SDCA_CTL(interrupt->function->desc->adr, interrupt->entity->id,
 			   SDCA_CTL_XU_FDL_STATUS, 0);
 	ret = regmap_read(interrupt->function_regmap, reg, &status);
-- 
2.47.3