blk-mq-sched: decide how to handle flush rq via RQF_FLUSH_SEQ

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In case of IO scheduler we always pre-allocate one driver tag before
calling blk_insert_flush(), and flush request will be marked as
RQF_FLUSH_SEQ once it is in flush machinery.

So if RQF_FLUSH_SEQ isn't set, we call blk_insert_flush() to handle
the request, otherwise the flush request is dispatched to ->dispatch
list directly.

This is a preparation patch for not preallocating a driver tag for flush
requests, and for not treating flush requests as a special case. This is
similar to what the legacy path does.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

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Ming Lei 2017-11-02 23:24:36 +08:00 • committed by Jens Axboe

parent 598906f814

commit a6a252e649

1 changed files with 16 additions and 13 deletions

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block/blk-mq-sched.c

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