spi: Fix controller unregister order

[ Upstream commit 84855678add8aba927faf76bc2f130a40f94b6f7 ]

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: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e5460d84ed088999e468d649f8be3e2406eb5654..57001f8f727a35af16f38fe448c10db605ddc8d3 100644 (file)
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1922,11 +1922,12 @@ void spi_unregister_master(struct spi_master *master)
                        dev_err(&master->dev, "queue remove failed\n");
        }
 
+       device_for_each_child(&master->dev, NULL, __unregister);
+
        mutex_lock(&board_lock);
        list_del(&master->list);
        mutex_unlock(&board_lock);
 
-       device_for_each_child(&master->dev, NULL, __unregister);
        device_unregister(&master->dev);
 }
 EXPORT_SYMBOL_GPL(spi_unregister_master);