[PATCH 3.14 27/77] blk-mq: use nr_cpu_ids as highest CPU ID count for hwq <-> cpu map

[Greg Kroah-Hartman]

3.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jens Axboe <axboe@xxxxxx>

commit a33c1ba2913802b6fb23e974bb2f6a4e73c8b7ce upstream.

We currently use num_possible_cpus(), but that breaks on sparc64 where
the CPU ID space is discontig. Use nr_cpu_ids as the highest CPU ID
instead, so we don't end up reading from invalid memory.

Signed-off-by: Jens Axboe <axboe@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 block/blk-mq-cpumap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/block/blk-mq-cpumap.c
+++ b/block/blk-mq-cpumap.c
@@ -95,7 +95,7 @@ unsigned int *blk_mq_make_queue_map(stru
 	unsigned int *map;
 
 	/* If cpus are offline, map them to first hctx */
-	map = kzalloc_node(sizeof(*map) * num_possible_cpus(), GFP_KERNEL,
+	map = kzalloc_node(sizeof(*map) * nr_cpu_ids, GFP_KERNEL,
 				reg->numa_node);
 	if (!map)
 		return NULL;


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