From: Bryan Freed <bfr...@chromium.org>
spi_pump_messages() calls into a controller driver with
unprepare_transfer_hardware() which is documented as "This may sleep".
As in the prepare_transfer_hardware() call below, we should release the
queue_lock spinlock before making the call.
Rework the logic a bit to hold queue_lock to protect the 'busy' flag,
then release it to call unprepare_transfer_hardware().
Signed-off-by: Bryan Freed <bfr...@chromium.org>
Reviewed-by: Doug Anderson <diand...@chromium.org>
Signed-off-by: Doug Anderson <diand...@chromium.org>
Acked-by: Linus Walleij <linus.wall...@linaro.org>
---
During a rebase we noticed that this old patch never actually landed
anywhere. I haven't gone through an reproduced the original bug on
ToT but I believe that this patch is still required. Perhaps it could
land somewhere? ;) Thanks!
drivers/spi/spi.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index f996c60..5b96250 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -543,17 +543,16 @@ static void spi_pump_messages(struct kthread_work *work)
/* Lock queue and check for queue work */
spin_lock_irqsave(&master->queue_lock, flags);
if (list_empty(&master->queue) || !master->running) {
- if (master->busy && master->unprepare_transfer_hardware) {
- ret = master->unprepare_transfer_hardware(master);
- if (ret) {
- spin_unlock_irqrestore(&master->queue_lock,
flags);
- dev_err(&master->dev,
- "failed to unprepare transfer
hardware\n");
- return;
- }
+ if (!master->busy) {
+ spin_unlock_irqrestore(&master->queue_lock, flags);
+ return;
}
master->busy = false;
spin_unlock_irqrestore(&master->queue_lock, flags);
+ if (master->unprepare_transfer_hardware &&
+ master->unprepare_transfer_hardware(master))
+ dev_err(&master->dev,
+ "failed to unprepare transfer hardware\n");
return;
}
--
1.8.1.3
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