spi: Unlock a spinlock before calling into the controller driver.

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 <bfreed@chromium.org>
Reviewed-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index f996c600eb8c..5b96250b0628 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;
         }