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Commit a2ef9471 authored by Daniel Vetter's avatar Daniel Vetter Committed by Linus Torvalds
Browse files

lib/ida: document locking requirements a bit better 

I wanted to wrap a bunch of ida_simple_get calls into their own locking,
until I dug around and read the original commit message.  Stuff like
this should imo be added to the kernel doc, let's do that.

Link: http://lkml.kernel.org/r/20161027072216.20411-1-daniel.vetter@ffwll.ch


Signed-off-by: default avatarDaniel Vetter <daniel.vetter@intel.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ce093a04

lib/idr.c

+11 −0
Original line number Diff line number Diff line
@@ -927,6 +927,9 @@ EXPORT_SYMBOL(ida_pre_get); 
 * and go back to the ida_pre_get() call.  If the ida is full, it will

 * return %-ENOSPC.

 *

 * Note that callers must ensure that concurrent access to @ida is not possible.

 * See ida_simple_get() for a varaint which takes care of locking.

 *

 * @p_id returns a value in the range @starting_id ... %0x7fffffff.

 */

int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
@@ -1073,6 +1076,9 @@ EXPORT_SYMBOL(ida_destroy); 
 * Allocates an id in the range start <= id < end, or returns -ENOSPC.

 * On memory allocation failure, returns -ENOMEM.

 *

 * Compared to ida_get_new_above() this function does its own locking, and

 * should be used unless there are special requirements.

 *

 * Use ida_simple_remove() to get rid of an id.

 */

int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
@@ -1119,6 +1125,11 @@ EXPORT_SYMBOL(ida_simple_get); 
 * ida_simple_remove - remove an allocated id.

 * @ida: the (initialized) ida.

 * @id: the id returned by ida_simple_get.

 *

 * Use to release an id allocated with ida_simple_get().

 *

 * Compared to ida_remove() this function does its own locking, and should be

 * used unless there are special requirements.

 */

void ida_simple_remove(struct ida *ida, unsigned int id)

{