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Unverified Commit 1a4327fb authored by Kirill Kapranov's avatar Kirill Kapranov Committed by Mark Brown
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spi: fix IDR collision on systems with both fixed and dynamic SPI bus numbers 



On systems where some controllers get a dynamic ID assigned and some have
a fixed number (e.g. from ACPI tables), the current implementation might
run into an IDR collision: in case of a fixed bus number is gotten by a
driver (but not marked busy in IDR tree) and a driver with dynamic bus
number gets the same ID and predictably fails.

Fix this by means of checking-in fixed IDsin IDR as far as dynamic ones
at the moment of the controller registration.

Fixes: 9b61e302 (spi: Pick spi bus number from Linux idr or spi alias)
Signed-off-by: default avatarKirill Kapranov <kirill.kapranov@compulab.co.il>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
parent 401c0d77

drivers/spi/spi.c

+9 −0
Original line number Diff line number Diff line
@@ -2170,6 +2170,15 @@ int spi_register_controller(struct spi_controller *ctlr) 
		if (WARN(id < 0, "couldn't get idr"))

			return id;

		ctlr->bus_num = id;

	} else {

		/* devices with a fixed bus num must check-in with the num */

		mutex_lock(&board_lock);

		id = idr_alloc(&spi_master_idr, ctlr, ctlr->bus_num,

			ctlr->bus_num + 1, GFP_KERNEL);

		mutex_unlock(&board_lock);

		if (WARN(id < 0, "couldn't get idr"))

			return id == -ENOSPC ? -EBUSY : id;

		ctlr->bus_num = id;

	}

	INIT_LIST_HEAD(&ctlr->queue);

	spin_lock_init(&ctlr->queue_lock);