releases/4.9.228/spi-fix-controller-unregister-order.patch

From f48538cd2d514a80c8a0ae47fc716fd373598720 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sashal@kernel.org>
Date: Fri, 15 May 2020 17:58:01 +0200
Subject: spi: Fix controller unregister order

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
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>
---
 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 7fec76dd532f..3fadc564d781 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2030,11 +2030,12 @@ 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);
-- 
2.25.1