Commit 33931808 authored Apr 27, 2017 by Jens Axboe

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 <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent a4e84aae

block/blk-mq-sched.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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;

		/*

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