spi: Fix controller unregister order

When an SPI controller unregisters, it unbinds all its slave devices.
For this, their drivers may need to access the SPI bus, e.g. to quiesce
interrupts.

However since commit ffbbdd21329f ("spi: create a message queueing
infrastructure"), spi_destroy_queue() is executed before unbinding the
slaves.  It sets ctlr->running = false, thereby preventing SPI bus
access and causing unbinding of slave devices to fail.

Fix by unbinding slaves before calling spi_destroy_queue().

Fixes: ffbbdd21329f ("spi: create a message queueing infrastructure")
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v3.4+
Cc: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/8aaf9d44c153fe233b17bc2dec4eb679898d7e7b.1589557526.git.lukas@wunner.de
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 531d1de85f7f6422e69bad0f046991b7b750ba2d..25eb96d329ab678cfbf216780ba0e56b3c4838d8 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2763,6 +2763,8 @@ void spi_unregister_controller(struct spi_controller *ctlr)
        struct spi_controller *found;
        int id = ctlr->bus_num;
 
+       device_for_each_child(&ctlr->dev, NULL, __unregister);
+
        /* First make sure that this controller was ever added */
        mutex_lock(&board_lock);
        found = idr_find(&spi_master_idr, id);
@@ -2775,7 +2777,6 @@ void spi_unregister_controller(struct spi_controller *ctlr)
        list_del(&ctlr->list);
        mutex_unlock(&board_lock);
 
-       device_for_each_child(&ctlr->dev, NULL, __unregister);
        device_unregister(&ctlr->dev);
        /* free bus id */
        mutex_lock(&board_lock);