linux-toradex.git/block/blk-mq-debugfs.c, branch toradex_4.20.y

block: add a report_zones method

2018-10-25T17:17:40+00:00

Dispatching a report zones command through the request queue is a major
pain due to the command reply payload rewriting necessary. Given that
blkdev_report_zones() is executing everything synchronously, implement
report zones as a block device file operation instead, allowing major
simplification of the code in many places.

sd, null-blk, dm-linear and dm-flakey being the only block device
drivers supporting exposing zoned block devices, these drivers are
modified to provide the device side implementation of the
report_zones() block device file operation.

For device mappers, a new report_zones() target type operation is
defined so that the upper block layer calls blkdev_report_zones() can
be propagated down to the underlying devices of the dm targets.
Implementation for this new operation is added to the dm-linear and
dm-flakey targets.

Reviewed-by: Hannes Reinecke 
Signed-off-by: Christoph Hellwig 
[Damien]
* Changed method block_device argument to gendisk
* Various bug fixes and improvements
* Added support for null_blk, dm-linear and dm-flakey.
Reviewed-by: Martin K. Petersen 
Reviewed-by: Mike Snitzer 
Signed-off-by: Damien Le Moal 
Signed-off-by: Jens Axboe

blk-mq-debugfs: Also show requests that have not yet been started

2018-10-05T14:16:58+00:00

When debugging e.g. the SCSI timeout handler it is important that
requests that have not yet been started or that already have
completed are also reported through debugfs.

Cc: Christoph Hellwig 
Cc: Ming Lei 
Cc: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Johannes Thumshirn 
Signed-off-by: Bart Van Assche 
Signed-off-by: Jens Axboe

block, scsi: Change the preempt-only flag into a counter

2018-09-26T21:11:28+00:00

The RQF_PREEMPT flag is used for three purposes:
- In the SCSI core, for making sure that power management requests
  are executed even if a device is in the "quiesced" state.
- For domain validation by SCSI drivers that use the parallel port.
- In the IDE driver, for IDE preempt requests.
Rename "preempt-only" into "pm-only" because the primary purpose of
this mode is power management. Since the power management core may
but does not have to resume a runtime suspended device before
performing system-wide suspend and since a later patch will set
"pm-only" mode as long as a block device is runtime suspended, make
it possible to set "pm-only" mode from more than one context. Since
with this change scsi_device_quiesce() is no longer idempotent, make
that function return early if it is called for a quiesced queue.

Signed-off-by: Bart Van Assche 
Acked-by: Martin K. Petersen 
Reviewed-by: Hannes Reinecke 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ming Lei 
Cc: Jianchao Wang 
Cc: Johannes Thumshirn 
Cc: Alan Stern 
Signed-off-by: Jens Axboe

blk-mq: dequeue request one by one from sw queue if hctx is busy

2018-07-09T15:07:53+00:00

It won't be efficient to dequeue request one by one from sw queue,
but we have to do that when queue is busy for better merge performance.

This patch takes the Exponential Weighted Moving Average(EWMA) to figure
out if queue is busy, then only dequeue request one by one from sw queue
when queue is busy.

Fixes: b347689ffbca ("blk-mq-sched: improve dispatching from sw queue")
Cc: Kashyap Desai 
Cc: Laurence Oberman 
Cc: Omar Sandoval 
Cc: Christoph Hellwig 
Cc: Bart Van Assche 
Cc: Hannes Reinecke 
Reported-by: Kashyap Desai 
Tested-by: Kashyap Desai 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

block: Make struct request_queue smaller for CONFIG_BLK_DEV_ZONED=n

2018-07-09T15:07:52+00:00

Exclude zoned block device members from struct request_queue for
CONFIG_BLK_DEV_ZONED == n. Avoid breaking the build by only building
the code that uses these struct request_queue members if
CONFIG_BLK_DEV_ZONED != n.

Signed-off-by: Bart Van Assche 
Reviewed-by: Damien Le Moal 
Cc: Matias Bjorling 
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: Inline blk_queue_nr_zones()

2018-07-09T15:07:52+00:00

Since the implementation of blk_queue_nr_zones() is trivial and since
it only has a single caller, inline this function.

Signed-off-by: Bart Van Assche 
Reviewed-by: Damien Le Moal 
Cc: Matias Bjorling 
Cc: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-mq-debugfs: Off by one in blk_mq_rq_state_name()

2018-06-20T17:26:04+00:00

If rq_state == ARRAY_SIZE() then we read one element beyond the end of
the blk_mq_rq_state_name_array[] array.

Fixes: ec6dcf63c55c ("blk-mq-debugfs: Show more request state information")
Reviewed-by: Bart Van Assche 
Signed-off-by: Dan Carpenter 
Signed-off-by: Jens Axboe

blk-mq: Remove generation seqeunce

2018-05-29T14:59:21+00:00

This patch simplifies the timeout handling by relying on the request
reference counting to ensure the iterator is operating on an inflight
and truly timed out request. Since the reference counting prevents the
tag from being reallocated, the block layer no longer needs to prevent
drivers from completing their requests while the timeout handler is
operating on it: a driver completing a request is allowed to proceed to
the next state without additional syncronization with the block layer.

This also removes any need for generation sequence numbers since the
request lifetime is prevented from being reallocated as a new sequence
while timeout handling is operating on it.

To enables this a refcount is added to struct request so that request
users can be sure they're operating on the same request without it
changing while they're processing it.  The request's tag won't be
released for reuse until both the timeout handler and the completion
are done with it.

Signed-off-by: Keith Busch 
[hch: slight cleanups, added back submission side hctx lock, use cmpxchg
 for completions]
Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

blk-mq: remove blk_mq_delay_queue()

2018-04-10T14:38:46+00:00

No driver uses this interface any more, so remove it.

Cc: Stefan Haberland 
Tested-by: Christian Borntraeger 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Ming Lei 
Signed-off-by: Jens Axboe

blk-mq-debugfs: Show more request state information

2018-03-17T20:41:17+00:00

Since commit 634f9e4631a8 ("blk-mq: remove REQ_ATOM_COMPLETE usages
from blk-mq") blk_rq_is_complete() only reports whether or not a
request has completed for legacy queues. Hence modify the
blk-mq-debugfs code such that it shows the blk-mq request state
again.

Fixes: 634f9e4631a8 ("blk-mq: remove REQ_ATOM_COMPLETE usages from blk-mq")
Signed-off-by: Bart Van Assche 
Cc: Tejun Heo 
Signed-off-by: Jens Axboe