spi: Fix controller unregister order

commit 84855678add8aba927faf76bc2f130a40f94b6f7 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 755221bc3745c0602bc1bb9a2e2dafbb890f3988..1fc29a665a4a531a345244fb4dad425147552247 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2768,6 +2768,8 @@ 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);
@@ -2780,7 +2782,6 @@ 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);