Commit 7d520d28 authored Aug 24, 2012 by Guenter Roeck Committed by Mark Brown Aug 27, 2012

spi/mxs: Fix device remove function



The call sequence spi_alloc_master/spi_register_master/spi_unregister_master
is complete; it reduces the device reference count to zero, which results in
device memory being freed. The remove function accesses the freed memory after
the call to spi_unregister_master(), _and_ it calls spi_master_put on the freed
memory.

Acquire a reference to the SPI master device and release it after cleanup is
complete (with the existing spi_master_put) to solve the problem.

Also, the device subsystem ensures that the remove function is only called once,
and resets device driver data to NULL. Remove the unnecessaary calls to
platform_set_drvdata().

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Marek Vasut <marex@denx.de>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

parent 41682e03

drivers/spi/spi-mxs.c

+1 −4

Original line number	Diff line number	Diff line
		@@ -586,7 +586,6 @@ static int __devinit mxs_spi_probe(struct platform_device *pdev)
		return 0;

		out_free_dma:
		platform_set_drvdata(pdev, NULL);
		dma_release_channel(ssp->dmach);
		clk_disable_unprepare(ssp->clk);
		out_master_free:
		@@ -600,14 +599,12 @@ static int __devexit mxs_spi_remove(struct platform_device *pdev)
		struct mxs_spi *spi;
		struct mxs_ssp *ssp;

		master = platform_get_drvdata(pdev);
		master = spi_master_get(platform_get_drvdata(pdev));
		spi = spi_master_get_devdata(master);
		ssp = &spi->ssp;

		spi_unregister_master(master);

		platform_set_drvdata(pdev, NULL);

		dma_release_channel(ssp->dmach);

		clk_disable_unprepare(ssp->clk);