The patch titled
Subject: lib/ida: document locking requirements a bit better
has been added to the -mm tree. Its filename is
lib-ida-document-locking-requirements-a-bit-better-v2.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-ida-document-locking-requirements-a-bit-better-v2.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-ida-document-locking-requirements-a-bit-better-v2.patch
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From: Daniel Vetter <daniel.vetter@xxxxxxxx>
Subject: 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@xxxxxxxx
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/idr.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff -puN lib/idr.c~lib-ida-document-locking-requirements-a-bit-better-v2 lib/idr.c
--- a/lib/idr.c~lib-ida-document-locking-requirements-a-bit-better-v2
+++ a/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)
{
_
Patches currently in -mm which might be from daniel.vetter@xxxxxxxx are
lib-ida-document-locking-requirements-a-bit-better-v2.patch
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