linux.git/include/linux/blkdev.h, branch v4.4-rc1

block: add block polling support

2015-11-07T17:40:47+00:00

Add basic support for polling for specific IO to complete. This uses
the cookie that blk-mq passes back, which enables the block layer
to pass this cookie to the driver to spin for a specific request.

This will be combined with request latency tracking, so we can make
qualified decisions about when to poll and when not to. For now, for
benchmark purposes, we add a sysfs file that controls whether polling
is enabled or not.

Signed-off-by: Jens Axboe 
Acked-by: Christoph Hellwig 
Acked-by: Keith Busch

block: change ->make_request_fn() and users to return a queue cookie

2015-11-07T17:40:46+00:00

No functional changes in this patch, but it prepares us for returning
a more useful cookie related to the IO that was queued up.

Signed-off-by: Jens Axboe 
Acked-by: Christoph Hellwig 
Acked-by: Keith Busch

Merge branch 'for-4.4/reservations' of git://git.kernel.dk/linux-block

2015-11-05T05:01:27+00:00

Pull block reservation support from Jens Axboe:
 "This adds support for persistent reservations, both at the core level,
  as well as for sd and NVMe"

[ Background from the docs: "Persistent Reservations allow restricting
  access to block devices to specific initiators in a shared storage
  setup.  All implementations are expected to ensure the reservations
  survive a power loss and cover all connections in a multi path
  environment" ]

* 'for-4.4/reservations' of git://git.kernel.dk/linux-block:
  NVMe: Precedence error in nvme_pr_clear()
  nvme: add missing endianess annotations in nvme_pr_command
  NVMe: Add persistent reservation ops
  sd: implement the Persistent Reservation API
  block: add an API for Persistent Reservations
  block: cleanup blkdev_ioctl

block: add an API for Persistent Reservations

2015-10-21T20:46:56+00:00

This commits adds a driver API and ioctls for controlling Persistent
Reservations s/genericly/generically/ at the block layer.  Persistent
Reservations are supported by SCSI and NVMe and allow controlling who gets
access to a device in a shared storage setup.

Note that we add a pr_ops structure to struct block_device_operations
instead of adding the members directly to avoid bloating all instances
of devices that will never support Persistent Reservations.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Jens Axboe

block: move blk_integrity to request_queue

2015-10-21T20:43:42+00:00

A trace like the following proceeds a crash in bio_integrity_process()
when it goes to use an already freed blk_integrity profile.

 BUG: unable to handle kernel paging request at ffff8800d31b10d8
 IP: [] 0xffff8800d31b10d8
 PGD 2f65067 PUD 21fffd067 PMD 80000000d30001e3
 Oops: 0011 [#1] SMP
 Dumping ftrace buffer:
 ---------------------------------
    ndctl-2222    2.... 44526245us : disk_release: pmem1s
 systemd--2223    4.... 44573945us : bio_integrity_endio: pmem1s
    <...>-409     4.... 44574005us : bio_integrity_process: pmem1s
 ---------------------------------
[..]
  Call Trace:
  [] ? bio_integrity_process+0x159/0x2d0
  [] bio_integrity_verify_fn+0x36/0x60
  [] process_one_work+0x1cc/0x4e0

Given that a request_queue is pinned while i/o is in flight and that a
gendisk is allowed to have a shorter lifetime, move blk_integrity to
request_queue to satisfy requests arriving after the gendisk has been
torn down.

Cc: Christoph Hellwig 
Cc: Martin K. Petersen 
[martin: fix the CONFIG_BLK_DEV_INTEGRITY=n case]
Tested-by: Ross Zwisler 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe

block: generic request_queue reference counting

2015-10-21T20:43:41+00:00

Allow pmem, and other synchronous/bio-based block drivers, to fallback
on a per-cpu reference count managed by the core for tracking queue
live/dead state.

The existing per-cpu reference count for the blk_mq case is promoted to
be used in all block i/o scenarios.  This involves initializing it by
default, waiting for it to drop to zero at exit, and holding a live
reference over the invocation of q->make_request_fn() in
generic_make_request().  The blk_mq code continues to take its own
reference per blk_mq request and retains the ability to freeze the
queue, but the check that the queue is frozen is moved to
generic_make_request().

This fixes crash signatures like the following:

 BUG: unable to handle kernel paging request at ffff880140000000
 [..]
 Call Trace:
  [] ? copy_user_handle_tail+0x5f/0x70
  [] pmem_do_bvec.isra.11+0x70/0xf0 [nd_pmem]
  [] pmem_make_request+0xd1/0x200 [nd_pmem]
  [] ? mempool_alloc+0x72/0x1a0
  [] generic_make_request+0xd6/0x110
  [] submit_bio+0x76/0x170
  [] submit_bh_wbc+0x12f/0x160
  [] submit_bh+0x12/0x20
  [] jbd2_write_superblock+0x8d/0x170
  [] jbd2_mark_journal_empty+0x5d/0x90
  [] jbd2_journal_destroy+0x24b/0x270
  [] ? put_pwq_unlocked+0x2a/0x30
  [] ? destroy_workqueue+0x225/0x250
  [] ext4_put_super+0x64/0x360
  [] generic_shutdown_super+0x6a/0xf0

Cc: Jens Axboe 
Cc: Keith Busch 
Cc: Ross Zwisler 
Suggested-by: Christoph Hellwig 
Reviewed-by: Christoph Hellwig 
Tested-by: Ross Zwisler 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe

block: Inline blk_integrity in struct gendisk

2015-10-21T20:42:42+00:00

Up until now the_integrity profile has been dynamically allocated and
attached to struct gendisk after the disk has been made active.

This causes problems because NVMe devices need to register the profile
prior to the partition table being read due to a mandatory metadata
buffer requirement. In addition, DM goes through hoops to deal with
preallocating, but not initializing integrity profiles.

Since the integrity profile is small (4 bytes + a pointer), Christoph
suggested moving it to struct gendisk proper. This requires several
changes:

 - Moving the blk_integrity definition to genhd.h.

 - Inlining blk_integrity in struct gendisk.

 - Removing the dynamic allocation code.

 - Adding helper functions which allow gendisk to set up and tear down
   the integrity sysfs dir when a disk is added/deleted.

 - Adding a blk_integrity_revalidate() callback for updating the stable
   pages bdi setting.

 - The calls that depend on whether a device has an integrity profile or
   not now key off of the bi->profile pointer.

 - Simplifying the integrity support routines in DM (Mike Snitzer).

Signed-off-by: Martin K. Petersen 
Reported-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Mike Snitzer 
Cc: Dan Williams 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe

block: Reduce the size of struct blk_integrity

2015-10-21T20:42:39+00:00

The per-device properties in the blk_integrity structure were previously
unsigned short. However, most of the values fit inside a char. The only
exception is the data interval size and we can work around that by
storing it as a power of two.

This cuts the size of the dynamic portion of blk_integrity in half.

Signed-off-by: Martin K. Petersen 
Reported-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe

block: Consolidate static integrity profile properties

2015-10-21T20:42:38+00:00

We previously made a complete copy of a device's data integrity profile
even though several of the fields inside the blk_integrity struct are
pointers to fixed template entries in t10-pi.c.

Split the static and per-device portions so that we can reference the
template directly.

Signed-off-by: Martin K. Petersen 
Reported-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Cc: Dan Williams 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe

block: Move integrity kobject to struct gendisk

2015-10-21T20:42:36+00:00

The integrity kobject purely exists to support the integrity
subdirectory in sysfs and doesn't really have anything to do with the
blk_integrity data structure. Move the kobject to struct gendisk where
it belongs.

Signed-off-by: Martin K. Petersen 
Reported-by: Christoph Hellwig 
Reviewed-by: Sagi Grimberg 
Signed-off-by: Dan Williams 
Signed-off-by: Jens Axboe