diff options
authorJens Axboe <>2017-04-27 07:45:46 -0600
committerJens Axboe <>2017-04-27 07:45:46 -0600
commit339318080b028fe347c279672da63c1cd5e52044 (patch)
parenta4e84aae8139aca9fbfbced1f45c51ca81b57488 (diff)
blk-mq-sched: alloate reserved tags out of normal pool
At least one driver, mtip32xx, has a hard coded dependency on the value of the reserved tag used for internal commands. While that should really be fixed up, for now let's ensure that we just bypass the scheduler tags an allocation marked as reserved. They are used for house keeping or error handling, so we can safely ignore them in the scheduler. Tested-by: Ming Lei <> Signed-off-by: Jens Axboe <>
1 files changed, 5 insertions, 1 deletions
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index e79e9f18d7c2..8b361e192e8a 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -82,7 +82,11 @@ struct request *blk_mq_sched_get_request(struct request_queue *q,
if (likely(!data->hctx))
data->hctx = blk_mq_map_queue(q, data->ctx->cpu);
- if (e) {
+ /*
+ * For a reserved tag, allocate a normal request since we might
+ * have driver dependencies on the value of the internal tag.
+ */
+ if (e && !(data->flags & BLK_MQ_REQ_RESERVED)) {
data->flags |= BLK_MQ_REQ_INTERNAL;