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spi/mpc52xx: Fix device remove function

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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. An extra call to spi_master_put is unnecessary
and results in an access to free memory.

At the same time, since the call to spi_unregister_master results in device
memory being freed, it must no longer be accessed afterwards.

To fix both problems, call spi_master_get to get an extra reference to the
device, and call spi_master_put only after the last access to device data.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
This commit is contained in:
Guenter Roeck 2012-08-18 09:29:22 -07:00 • committed by Mark Brown
parent 866c0f25d2
commit f95e1028e3
1 changed files with 2 additions and 2 deletions
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4
drivers/spi/spi-mpc52xx.c
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@ -529,7 +529,7 @@ static int __devinit mpc52xx_spi_probe(struct platform_device *op)
static int __devexit mpc52xx_spi_remove(struct platform_device *op) static int __devexit mpc52xx_spi_remove(struct platform_device *op)
{ {
struct spi_master *master = dev_get_drvdata(&op->dev); struct spi_master *master = spi_master_get(dev_get_drvdata(&op->dev));
struct mpc52xx_spi *ms = spi_master_get_devdata(master); struct mpc52xx_spi *ms = spi_master_get_devdata(master);
int i; int i;
@ -541,8 +541,8 @@ static int __devexit mpc52xx_spi_remove(struct platform_device *op)
kfree(ms->gpio_cs); kfree(ms->gpio_cs);
spi_unregister_master(master); spi_unregister_master(master);
spi_master_put(master);
iounmap(ms->regs); iounmap(ms->regs);
spi_master_put(master);
return 0; return 0;
} }