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Commit ea98eed9 authored by Eric Paris's avatar Eric Paris Committed by Linus Torvalds
Browse files

flex_array: add helpers to get and put to make pointers easy to use 



Getting and putting arrays of pointers with flex arrays is a PITA.  You
have to remember to pass &ptr to the _put and you have to do weird and
wacky casting to get the ptr back from the _get.  Add two functions
flex_array_get_ptr() and flex_array_put_ptr() to handle all of the magic.

[akpm@linux-foundation.org: simplification suggested by Joe]
Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: Joe Perches <joe@perches.com>
Cc: James Morris <jmorris@namei.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 559b140a

include/linux/flex_array.h

+5 −0
Original line number Diff line number Diff line
@@ -70,4 +70,9 @@ int flex_array_clear(struct flex_array *fa, unsigned int element_nr); 
void *flex_array_get(struct flex_array *fa, unsigned int element_nr);

int flex_array_shrink(struct flex_array *fa);



#define flex_array_put_ptr(fa, nr, src, gfp) \

	flex_array_put(fa, nr, &(void *)(src), gfp)



void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr);



#endif /* _FLEX_ARRAY_H */

lib/flex_array.c

+24 −1
Original line number Diff line number Diff line
@@ -171,6 +171,8 @@ __fa_get_part(struct flex_array *fa, int part_nr, gfp_t flags) 
 * Note that this *copies* the contents of @src into

 * the array.  If you are trying to store an array of

 * pointers, make sure to pass in &ptr instead of ptr.

 * You may instead wish to use the flex_array_put_ptr()

 * helper function.

 *

 * Locking must be provided by the caller.

 */
@@ -265,7 +267,8 @@ int flex_array_prealloc(struct flex_array *fa, unsigned int start, 
 *

 * Returns a pointer to the data at index @element_nr.  Note

 * that this is a copy of the data that was passed in.  If you

 * are using this to store pointers, you'll get back &ptr.

 * are using this to store pointers, you'll get back &ptr.  You

 * may instead wish to use the flex_array_get_ptr helper.

 *

 * Locking must be provided by the caller.

 */
@@ -286,6 +289,26 @@ void *flex_array_get(struct flex_array *fa, unsigned int element_nr) 
	return &part->elements[index_inside_part(fa, element_nr)];

}



/**

 * flex_array_get_ptr - pull a ptr back out of the array

 * @fa:		the flex array from which to extract data

 * @element_nr:	index of the element to fetch from the array

 *

 * Returns the pointer placed in the flex array at element_nr using

 * flex_array_put_ptr().  This function should not be called if the

 * element in question was not set using the _put_ptr() helper.

 */

void *flex_array_get_ptr(struct flex_array *fa, unsigned int element_nr)

{

	void **tmp;



	tmp = flex_array_get(fa, element_nr);

	if (!tmp)

		return NULL;



	return *tmp;

}



static int part_is_free(struct flex_array_part *part)

{

	int i;