[4.19,059/267] spi: Fix controller unregister order

Message ID 20200619141651.697715454@linuxfoundation.org
State New
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  • Untitled series #28331
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Commit Message

Greg Kroah-Hartman June 19, 2020, 2:30 p.m.
From: Lukas Wunner <lukas@wunner.de>

[ 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

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>
 drivers/spi/spi.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)


diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 0022a49797f9..f589d8100e95 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2306,6 +2306,8 @@  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 */
 	found = idr_find(&spi_master_idr, id);
@@ -2318,7 +2320,6 @@  void spi_unregister_controller(struct spi_controller *ctlr)
-	device_for_each_child(&ctlr->dev, NULL, __unregister);
 	/* free bus id */