[PATCH] SPI cleanup() method param becomes non-const

I'd like to assign NULL to kfree()d members of a structure.  I can't do
that without ugly casting (see the PXA patch) when the structure pointed to
is const-qualified.  I don't really see a reason why the cleanup method
isn't allowed to alter the object it should clean up.  :-)

No, I didn't test the PXA patch, but I verified that the NULL-assignment
doesn't stop me from doing rmmod/insmodding my own spi_bitbang-based
driver.

Signed-off-by: Hans-Peter Nilsson <hp@axis.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/spi/pxa2xx_spi.c

@@ -1214,9 +1214,9 @@ static int setup(struct spi_device *spi)
 	return 0;
 }
 
-static void cleanup(const struct spi_device *spi)
+static void cleanup(struct spi_device *spi)
 {
-	struct chip_data *chip = spi_get_ctldata((struct spi_device *)spi);
+	struct chip_data *chip = spi_get_ctldata(spi);
 
 	kfree(chip);
 }

drivers/spi/spi.c

@@ -32,7 +32,7 @@
  */
 static void spidev_release(struct device *dev)
 {
-	const struct spi_device	*spi = to_spi_device(dev);
+	struct spi_device	*spi = to_spi_device(dev);
 
 	/* spi masters may cleanup for released devices */
 	if (spi->master->cleanup)

drivers/spi/spi_bitbang.c

@@ -238,7 +238,7 @@ EXPORT_SYMBOL_GPL(spi_bitbang_setup);
 /**
  * spi_bitbang_cleanup - default cleanup for per-word I/O loops
  */
-void spi_bitbang_cleanup(const struct spi_device *spi)
+void spi_bitbang_cleanup(struct spi_device *spi)
 {
 	kfree(spi->controller_state);
 }

include/linux/spi/spi.h

@@ -220,7 +220,7 @@ struct spi_master {
 						struct spi_message *mesg);
 
 	/* called on release() to free memory provided by spi_master */
-	void			(*cleanup)(const struct spi_device *spi);
+	void			(*cleanup)(struct spi_device *spi);
 };
 
 static inline void *spi_master_get_devdata(struct spi_master *master)

include/linux/spi/spi_bitbang.h

@@ -55,7 +55,7 @@ struct spi_bitbang {
  * methods, if you like.
  */
 extern int spi_bitbang_setup(struct spi_device *spi);
-extern void spi_bitbang_cleanup(const struct spi_device *spi);
+extern void spi_bitbang_cleanup(struct spi_device *spi);
 extern int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m);
 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
 				      struct spi_transfer *t);