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authorGuenter Roeck <linux@roeck-us.net>2015-09-06 01:46:54 +0300
committerMark Brown <broonie@kernel.org>2015-09-06 01:08:29 +0100
commita394d635193b641f2c86ead5ada5b115d57c51f8 (patch)
tree56e3d96fb8729966fe72e8155ee40f8d5e9e27df
parentd770e558e21961ad6cfdf0ff7df0eb5d7d4f0754 (diff)
downloadlinux-a394d635193b641f2c86ead5ada5b115d57c51f8.tar.bz2
spi: Fix documentation of spi_alloc_master()
Actually, spi_master_put() after spi_alloc_master() must _not_ be followed by kfree(). The memory is already freed with the call to spi_master_put() through spi_master_class, which registers a release function. Calling both spi_master_put() and kfree() results in often nasty (and delayed) crashes elsewhere in the kernel, often in the networking stack. This reverts commit eb4af0f5349235df2e4a5057a72fc8962d00308a. Link to patch and concerns: https://lkml.org/lkml/2012/9/3/269 or http://lkml.iu.edu/hypermail/linux/kernel/1209.0/00790.html Alexey Klimov: This revert becomes valid after 94c69f765f1b4a658d96905ec59928e3e3e07e6a when spi-imx.c has been fixed and there is no need to call kfree() so comment for spi_alloc_master() should be fixed. Signed-off-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: stable@vger.kernel.org
-rw-r--r--drivers/spi/spi.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index cf8b91b23a76..9ce2f156d382 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1437,8 +1437,7 @@ static struct class spi_master_class = {
*
* The caller is responsible for assigning the bus number and initializing
* the master's methods before calling spi_register_master(); and (after errors
- * adding the device) calling spi_master_put() and kfree() to prevent a memory
- * leak.
+ * adding the device) calling spi_master_put() to prevent a memory leak.
*/
struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
{