linux-stable.git/block/elevator.c, branch v4.18.2

block: split the blk-mq case from elevator_init

2018-06-01T13:38:21+00:00

There is almost no shared logic, which leads to a very confusing code
flow.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: move sysfs_lock into elevator_init

2018-06-01T13:38:19+00:00

Both callers take just around so function call, so move it in.
Also remove the now pointless blk_mq_sched_init wrapper.

Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: remove the always unused name argument to elevator_init

2018-06-01T13:38:17+00:00

Reported-by: Damien Le Moal 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: unexport elevator_init/exit

2018-06-01T13:38:16+00:00

These are only used by the block core.  Also move the declarations to
block/blk.h.

Reported-by: Damien Le Moal 
Signed-off-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: move initialization of elevator-related fields to blk_alloc_queue_node

2018-06-01T13:38:14+00:00

No point in doing this in elevator_init.

Signed-off-by: Christoph Hellwig 
Reported-by: Damien Le Moal 
Reviewed-by: Damien Le Moal 
Tested-by: Damien Le Moal 
Signed-off-by: Jens Axboe

block: Document scheduler modification locking requirements

2018-01-18T19:54:42+00:00

This patch does not change any functionality.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe

block: Unexport elv_register_queue() and elv_unregister_queue()

2018-01-18T19:54:41+00:00

These two functions are only called from inside the block layer so
unexport them.

Reviewed-by: Christoph Hellwig 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe

blk-mq: quiesce queue during switching io sched and updating nr_requests

2018-01-06T16:25:36+00:00

Dispatch may still be in-progress after queue is frozen, so we have to
quiesce queue before switching IO scheduler and updating nr_requests.

Also when switching io schedulers, blk_mq_run_hw_queue() may still be
called somewhere(such as from nvme_reset_work()), and io scheduler's
per-hctx data may not be setup yet, so cause oops even inside
blk_mq_hctx_has_pending(), such as it can be run just between:

        ret = e->ops.mq.init_sched(q, e);
AND
        ret = e->ops.mq.init_hctx(hctx, i)

inside blk_mq_init_sched().

This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue()
after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending
won't be called if queue is quiesced.

Reviewed-by: Christoph Hellwig 
Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen)
Reported-by: Yi Zhang 
Tested-by: Yi Zhang 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

elevator: allow name aliases

2017-10-25T18:36:50+00:00

Since we now lookup elevator types with the appropriate multiqueue
capability, allow schedulers to register with an alias alongside
the real name. This is in preparation for allowing 'mq-deadline'
to register an alias of 'deadline' as well.

Reviewed-by: Omar Sandoval 
Signed-off-by: Jens Axboe

elevator: lookup mq vs non-mq elevators

2017-10-25T18:36:45+00:00

If an IO scheduler is selected via elevator= and it doesn't match
the driver in question wrt blk-mq support, then we fail to boot.

The elevator= parameter is deprecated and only supported for
non-mq devices. Augment the elevator lookup API so that we
pass in if we're looking for an mq capable scheduler or not,
so that we only ever return a valid type for the queue in
question.

Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=196695
Reviewed-by: Omar Sandoval 
Signed-off-by: Jens Axboe