Commit 09d1ea1c authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Greg Kroah-Hartman
Browse files

devres: provide devm_kstrdup_const() 



Provide a resource managed version of kstrdup_const(). This variant
internally calls devm_kstrdup() on pointers that are outside of
.rodata section and returns the string as is otherwise.

Make devm_kfree() check if the passed pointer doesn't point to .rodata
and if so - don't actually destroy the resource.

Signed-off-by: default avatarBartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Acked-by: default avatarMike Rapoport <rppt@linux.vnet.ibm.com>
Acked-by: default avatarRasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 59c3f82a

drivers/base/devres.c

+31 −0
Original line number Diff line number Diff line
@@ -11,6 +11,8 @@ 
#include <linux/slab.h>

#include <linux/percpu.h>



#include <asm/sections.h>



#include "base.h"



struct devres_node {
@@ -822,6 +824,28 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) 
}

EXPORT_SYMBOL_GPL(devm_kstrdup);



/**

 * devm_kstrdup_const - resource managed conditional string duplication

 * @dev: device for which to duplicate the string

 * @s: the string to duplicate

 * @gfp: the GFP mask used in the kmalloc() call when allocating memory

 *

 * Strings allocated by devm_kstrdup_const will be automatically freed when

 * the associated device is detached.

 *

 * RETURNS:

 * Source string if it is in .rodata section otherwise it falls back to

 * devm_kstrdup.

 */

const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)

{

	if (is_kernel_rodata((unsigned long)s))

		return s;



	return devm_kstrdup(dev, s, gfp);

}

EXPORT_SYMBOL_GPL(devm_kstrdup_const);



/**

 * devm_kvasprintf - Allocate resource managed space and format a string

 *		     into that.
@@ -889,6 +913,13 @@ void devm_kfree(struct device *dev, const void *p) 
{

	int rc;



	/*

	 * Special case: pointer to a string in .rodata returned by

	 * devm_kstrdup_const().

	 */

	if (unlikely(is_kernel_rodata((unsigned long)p)))

		return;



	rc = devres_destroy(dev, devm_kmalloc_release,

			    devm_kmalloc_match, (void *)p);

	WARN_ON(rc);

include/linux/device.h

+2 −0
Original line number Diff line number Diff line
@@ -696,6 +696,8 @@ static inline void *devm_kcalloc(struct device *dev, 
}

extern void devm_kfree(struct device *dev, const void *p);

extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;

extern const char *devm_kstrdup_const(struct device *dev,

				      const char *s, gfp_t gfp);

extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,

			  gfp_t gfp);

CRA Git | Maintained and supported by SUSTech CRA and CCSE