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authorDaniel Vetter <daniel.vetter@ffwll.ch>2016-12-12 16:46:20 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 18:55:09 -0800
commita2ef9471c771427c2ddd56677b8de45021f6fd71 (patch)
tree708404faa2d25e02dae713f8e60cd7c9430a4f89 /lib/idr.c
parentce093a04543c403d52c1a5788d8cb92e47453aba (diff)
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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: Daniel Vetter <daniel.vetter@intel.com> Acked-by: Tejun 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/idr.c')
-rw-r--r--lib/idr.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/lib/idr.c b/lib/idr.c
index 6098336df267..52d2979a05e8 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -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)
{