Commit Graph

251 Commits

Author SHA1 Message Date
Christoph Hellwig
746cd1e7e4 block: use blkdev_issue_discard in blk_ioctl_discard
blk_ioctl_discard duplicates large amounts of code from blkdev_issue_discard,
the only difference between the two is that blkdev_issue_discard needs to
send a barrier discard request and blk_ioctl_discard a non-barrier one,
and blk_ioctl_discard needs to wait on the request.  To facilitates this
add a flags argument to blkdev_issue_discard to control both aspects of the
behaviour.  This will be very useful later on for using the waiting
funcitonality for other callers.

Based on an earlier patch from Matthew Wilcox <matthew@wil.cx>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:53 +02:00
Martin K. Petersen
3c5820c743 block: Optimal I/O limit wrapper
Implement blk_limits_io_opt() and make blk_queue_io_opt() a wrapper
around it. DM needs this to avoid poking at the queue_limits directly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-14 08:24:52 +02:00
Jens Axboe
01e97f6b89 block: enable rq CPU completion affinity by default
Test results here look good, and on big OLTP runs it has also shown
to significantly increase cycles attributed to the database and
cause a performance boost.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:34:33 +02:00
Jens Axboe
fb1e75389b block: improve queue_should_plug() by looking at IO depths
Instead of just checking whether this device uses block layer
tagging, we can improve the detection by looking at the maximum
queue depth it has reached. If that crosses 4, then deem it a
queuing device.

This is important on high IOPS devices, since plugging hurts
the performance there (it can be as much as 10-15% of the sys
time).

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Jens Axboe
1f98a13f62 bio: first step in sanitizing the bio->bi_rw flag testing
Get rid of any functions that test for these bits and make callers
use bio_rw_flagged() directly. Then it is at least directly apparent
what variable and flag they check.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:31 +02:00
Tejun Heo
80a761fd33 block: implement mixed merge of different failfast requests
Failfast has characteristics from other attributes.  When issuing,
executing and successuflly completing requests, failfast doesn't make
any difference.  It only affects how a request is handled on failure.
Allowing requests with different failfast settings to be merged cause
normal IOs to fail prematurely while not allowing has performance
penalties as failfast is used for read aheads which are likely to be
located near in-flight or to-be-issued normal IOs.

This patch introduces the concept of 'mixed merge'.  A request is a
mixed merge if it is merge of segments which require different
handling on failure.  Currently the only mixable attributes are
failfast ones (or lack thereof).

When a bio with different failfast settings is added to an existing
request or requests of different failfast settings are merged, the
merged request is marked mixed.  Each bio carries failfast settings
and the request always tracks failfast state of the first bio.  When
the request fails, blk_rq_err_bytes() can be used to determine how
many bytes can be safely failed without crossing into an area which
requires further retrials.

This allows request merging regardless of failfast settings while
keeping the failure handling correct.

This patch only implements mixed merge but doesn't enable it.  The
next one will update SCSI to make use of mixed merge.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Niel Lambrechts <niel.lambrechts@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:30 +02:00
Tejun Heo
a82afdfcb8 block: use the same failfast bits for bio and request
bio and request use the same set of failfast bits.  This patch makes
the following changes to simplify things.

* enumify BIO_RW* bits and reorder bits such that BIOS_RW_FAILFAST_*
  bits coincide with __REQ_FAILFAST_* bits.

* The above pushes BIO_RW_AHEAD out of sync with __REQ_FAILFAST_DEV
  but the matching is useless anyway.  init_request_from_bio() is
  responsible for setting FAILFAST bits on FS requests and non-FS
  requests never use BIO_RW_AHEAD.  Drop the code and comment from
  blk_rq_bio_prep().

* Define REQ_FAILFAST_MASK which is OR of all FAILFAST bits and
  simplify FAILFAST flags handling in init_request_from_bio().

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-09-11 14:33:27 +02:00
Martin K. Petersen
7c958e3264 block: Add a wrapper for setting minimum request size without a queue
Introduce blk_limits_io_min() and make blk_queue_io_min() call it.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-08-01 10:24:35 +02:00
Trond Myklebust
373c0a7ed3 Fix compile error due to congestion_wait() changes
Move the definition of BLK_RW_ASYNC/BLK_RW_SYNC into linux/backing-dev.h
so that it is available to all callers of set/clear_bdi_congested().

This replaces commit 097041e576 ("fuse:
Fix build error"), which will be reverted.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-07-11 11:22:26 -07:00
FUJITA Tomonori
ecb554a846 block: fix sg SG_DXFER_TO_FROM_DEV regression
I overlooked SG_DXFER_TO_FROM_DEV support when I converted sg to use
the block layer mapping API (2.6.28).

Douglas Gilbert explained SG_DXFER_TO_FROM_DEV:

http://www.spinics.net/lists/linux-scsi/msg37135.html

=
The semantics of SG_DXFER_TO_FROM_DEV were:
   - copy user space buffer to kernel (LLD) buffer
   - do SCSI command which is assumed to be of the DATA_IN
     (data from device) variety. This would overwrite
     some or all of the kernel buffer
   - copy kernel (LLD) buffer back to the user space.

The idea was to detect short reads by filling the original
user space buffer with some marker bytes ("0xec" it would
seem in this report). The "resid" value is a better way
of detecting short reads but that was only added this century
and requires co-operation from the LLD.
=

This patch changes the block layer mapping API to support this
semantics. This simply adds another field to struct rq_map_data and
enables __bio_copy_iov() to copy data from user space even with READ
requests.

It's better to add the flags field and kills null_mapped and the new
from_user fields in struct rq_map_data but that approach makes it
difficult to send this patch to stable trees because st and osst
drivers use struct rq_map_data (they were converted to use the block
layer in 2.6.29 and 2.6.30). Well, I should clean up the block layer
mapping API.

zhou sf reported this regiression and tested this patch:

http://www.spinics.net/lists/linux-scsi/msg37128.html
http://www.spinics.net/lists/linux-scsi/msg37168.html

Reported-by: zhou sf <sxzzsf@gmail.com>
Tested-by: zhou sf <sxzzsf@gmail.com>
Cc: stable@kernel.org
Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:53 +02:00
Jens Axboe
8aa7e847d8 Fix congestion_wait() sync/async vs read/write confusion
Commit 1faa16d228 accidentally broke
the bdi congestion wait queue logic, causing us to wait on congestion
for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-10 20:31:53 +02:00
Jens Axboe
018e044689 block: get rid of queue-private command filter
The initial patches to support this through sysfs export were broken
and have been if 0'ed out in any release. So lets just kill the code
and reclaim some space in struct request_queue, if anyone would later
like to fixup the sysfs bits, the git history can easily restore
the removed bits.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-07-01 10:56:26 +02:00
Martin K. Petersen
e475bba2fd block: Introduce helper to reset queue limits to default values
DM reuses the request queue when swapping in a new device table
Introduce blk_set_default_limits() which can be used to reset the the
queue_limits prior to stacking devices.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Alasdair G Kergon <agk@redhat.com>
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-16 08:23:52 +02:00
Linus Torvalds
d614aec475 Merge branch 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
* 'for-2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (29 commits)
  ide: re-implement ide_pci_init_one() on top of ide_pci_init_two()
  ide: unexport ide_find_dma_mode()
  ide: fix PowerMac bootup oops
  ide: skip probe if there are no devices on the port (v2)
  sl82c105: add printk() logging facility
  ide-tape: fix proc warning
  ide: add IDE_DFLAG_NIEN_QUIRK device flag
  ide: respect quirk_drives[] list on all controllers
  hpt366: enable all quirks for devices on quirk_drives[] list
  hpt366: sync quirk_drives[] list with pdc202xx_{new,old}.c
  ide: remove superfluous SELECT_MASK() call from do_rw_taskfile()
  ide: remove superfluous SELECT_MASK() call from ide_driveid_update()
  icside: remove superfluous ->maskproc method
  ide-tape: fix IDE_AFLAG_* atomic accesses
  ide-tape: change IDE_AFLAG_IGNORE_DSC non-atomically
  pdc202xx_old: kill resetproc() method
  pdc202xx_old: don't call pdc202xx_reset() on IRQ timeout
  pdc202xx_old: use ide_dma_test_irq()
  ide: preserve Host Protected Area by default (v2)
  ide-gd: implement block device ->set_capacity method (v2)
  ...
2009-06-12 09:29:42 -07:00
Kiyoshi Ueda
b0fd271d5f block: add request clone interface (v2)
This patch adds the following 2 interfaces for request-stacking drivers:

  - blk_rq_prep_clone(struct request *clone, struct request *orig,
		      struct bio_set *bs, gfp_t gfp_mask,
		      int (*bio_ctr)(struct bio *, struct bio*, void *),
		      void *data)
      * Clones bios in the original request to the clone request
        (bio_ctr is called for each cloned bios.)
      * Copies attributes of the original request to the clone request.
        The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not
        copied.

  - blk_rq_unprep_clone(struct request *clone)
      * Frees cloned bios from the clone request.

Request stacking drivers (e.g. request-based dm) need to make a clone
request for a submitted request and dispatch it to other devices.

To allocate request for the clone, request stacking drivers may not
be able to use blk_get_request() because the allocation may be done
in an irq-disabled context.
So blk_rq_prep_clone() takes a request allocated by the caller
as an argument.

For each clone bio in the clone request, request stacking drivers
should be able to set up their own completion handler.
So blk_rq_prep_clone() takes a callback function which is called
for each clone bio, and a pointer for private data which is passed
to the callback.

NOTE:
blk_rq_prep_clone() doesn't copy any actual data of the original
request.  Pages are shared between original bios and cloned bios.
So caller must not complete the original request before the clone
request.

Signed-off-by: Kiyoshi Ueda <k-ueda@ct.jp.nec.com>
Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-11 13:11:05 +02:00
Jens Axboe
9df1bb9b51 Revert "block: Fix bounce limit setting in DM"
This reverts commit a05c0205ba.

DM doesn't need to access the bounce_pfn directly.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-09 06:22:57 +02:00
Bartlomiej Zolnierkiewicz
db429e9ec0 partitions: add ->set_capacity block device method
* Add ->set_capacity block device method and use it in rescan_partitions()
  to attempt enabling native capacity of the device upon detecting the
  partition which exceeds device capacity.

* Add GENHD_FL_NATIVE_CAPACITY flag to try limit attempts of enabling
  native capacity during partition scan.

Together with the consecutive patch implementing ->set_capacity method in
ide-gd device driver this allows automatic disabling of Host Protected Area
(HPA) if any partitions overlapping HPA are detected.

Cc: Robert Hancock <hancockrwd@gmail.com>
Cc: Frans Pop <elendil@planet.nl>
Cc: "Andries E. Brouwer" <Andries.Brouwer@cwi.nl>
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Emphatically-Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-06-07 13:52:52 +02:00
Martin K. Petersen
a05c0205ba block: Fix bounce limit setting in DM
blk_queue_bounce_limit() is more than a wrapper about the request queue
limits.bounce_pfn variable.  Introduce blk_queue_bounce_pfn() which can
be called by stacking drivers that wish to set the bounce limit
explicitly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-06-03 09:33:18 +02:00
Martin K. Petersen
c72758f337 block: Export I/O topology for block devices and partitions
To support devices with physical block sizes bigger than 512 bytes we
need to ensure proper alignment.  This patch adds support for exposing
I/O topology characteristics as devices are stacked.

  logical_block_size is the smallest unit the device can address.

  physical_block_size indicates the smallest I/O the device can write
  without incurring a read-modify-write penalty.

  The io_min parameter is the smallest preferred I/O size reported by
  the device.  In many cases this is the same as the physical block
  size.  However, the io_min parameter can be scaled up when stacking
  (RAID5 chunk size > physical block size).

  The io_opt characteristic indicates the optimal I/O size reported by
  the device.  This is usually the stripe width for arrays.

  The alignment_offset parameter indicates the number of bytes the start
  of the device/partition is offset from the device's natural alignment.
  Partition tools and MD/DM utilities can use this to pad their offsets
  so filesystems start on proper boundaries.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:55 +02:00
Martin K. Petersen
025146e13b block: Move queue limits to an embedded struct
To accommodate stacking drivers that do not have an associated request
queue we're moving the limits to a separate, embedded structure.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:55 +02:00
Martin K. Petersen
ae03bf639a block: Use accessor functions for queue limits
Convert all external users of queue limits to using wrapper functions
instead of poking the request queue variables directly.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Martin K. Petersen
e1defc4ff0 block: Do away with the notion of hardsect_size
Until now we have had a 1:1 mapping between storage device physical
block size and the logical block sized used when addressing the device.
With SATA 4KB drives coming out that will no longer be the case.  The
sector size will be 4KB but the logical block size will remain
512-bytes.  Hence we need to distinguish between the physical block size
and the logical ditto.

This patch renames hardsect_size to logical_block_size.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 23:22:54 +02:00
Jens Axboe
e4b636366c Merge branch 'master' into for-2.6.31
Conflicts:
	drivers/block/hd.c
	drivers/block/mg_disk.c

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-22 20:25:34 +02:00
Jens Axboe
0a7ae2ff0d block: change the tag sync vs async restriction logic
Make them fully share the tag space, but disallow async requests using
the last any two slots.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-20 08:54:31 +02:00
Boaz Harrosh
a411f4bbb8 block: Un-export blk_rq_append_bio
OSD was the last in-tree user of blk_rq_append_bio(). Now
that it is fixed blk_rq_append_bio is un-exported and
is only used internally by block layer.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 12:14:56 +02:00
Boaz Harrosh
79eb63e9e5 block: Add blk_make_request(), takes bio, returns a request
New block API:
given a struct bio allocates a new request. This is the parallel of
generic_make_request for BLOCK_PC commands users.

The passed bio may be a chained-bio. The bio is bounced if needed
inside the call to this member.

This is in the effort of un-exporting blk_rq_append_bio().

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
CC: Jeff Garzik <jeff@garzik.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-19 12:14:56 +02:00
FUJITA Tomonori
b1f744937f block: move completion related functions back to blk-core.c
Let's put the completion related functions back to block/blk-core.c
where they have lived. We can also unexport blk_end_bidi_request() and
__blk_end_bidi_request(), which nobody uses.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 11:06:48 +02:00
FUJITA Tomonori
1822952ba2 block: let blk_end_request_all handle bidi requests
blk_end_request_all() and __blk_end_request_all() should finish all
bytes including bidi, by definition. That's what all bidi users need ,
bidi requests must be complete as a whole (partial completion is
impossible).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 11:06:47 +02:00
Tejun Heo
9934c8c045 block: implement and enforce request peek/start/fetch
Till now block layer allowed two separate modes of request execution.
A request is always acquired from the request queue via
elv_next_request().  After that, drivers are free to either dequeue it
or process it without dequeueing.  Dequeue allows elv_next_request()
to return the next request so that multiple requests can be in flight.

Executing requests without dequeueing has its merits mostly in
allowing drivers for simpler devices which can't do sg to deal with
segments only without considering request boundary.  However, the
benefit this brings is dubious and declining while the cost of the API
ambiguity is increasing.  Segment based drivers are usually for very
old or limited devices and as converting to dequeueing model isn't
difficult, it doesn't justify the API overhead it puts on block layer
and its more modern users.

Previous patches converted all block low level drivers to dequeueing
model.  This patch completes the API transition by...

* renaming elv_next_request() to blk_peek_request()

* renaming blkdev_dequeue_request() to blk_start_request()

* adding blk_fetch_request() which is combination of peek and start

* disallowing completion of queued (not started) requests

* applying new API to all LLDs

Renamings are for consistency and to break out of tree code so that
it's apparent that out of tree drivers need updating.

[ Impact: block request issue API cleanup, no functional change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: unsik Kim <donari75@gmail.com>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Laurent Vivier <Laurent@lvivier.info>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Adrian McMenamin <adrian@mcmen.demon.co.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:52:18 +02:00
Tejun Heo
a2dec7b363 block: hide request sector and data_len
Block low level drivers for some reason have been pretty good at
abusing block layer API.  Especially struct request's fields tend to
get violated in all possible ways.  Make it clear that low level
drivers MUST NOT access or manipulate rq->sector and rq->data_len
directly by prefixing them with double underscores.

This change is also necessary to break build of out-of-tree codes
which assume the previous block API where internal fields can be
manipulated and rq->data_len carries residual count on completion.

[ Impact: hide internal fields, block API change ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:55 +02:00
Tejun Heo
2e46e8b27a block: drop request->hard_* and *nr_sectors
struct request has had a few different ways to represent some
properties of a request.  ->hard_* represent block layer's view of the
request progress (completion cursor) and the ones without the prefix
are supposed to represent the issue cursor and allowed to be updated
as necessary by the low level drivers.  The thing is that as block
layer supports partial completion, the two cursors really aren't
necessary and only cause confusion.  In addition, manual management of
request detail from low level drivers is cumbersome and error-prone at
the very least.

Another interesting duplicate fields are rq->[hard_]nr_sectors and
rq->{hard_cur|current}_nr_sectors against rq->data_len and
rq->bio->bi_size.  This is more convoluted than the hard_ case.

rq->[hard_]nr_sectors are initialized for requests with bio but
blk_rq_bytes() uses it only for !pc requests.  rq->data_len is
initialized for all request but blk_rq_bytes() uses it only for pc
requests.  This causes good amount of confusion throughout block layer
and its drivers and determining the request length has been a bit of
black magic which may or may not work depending on circumstances and
what the specific LLD is actually doing.

rq->{hard_cur|current}_nr_sectors represent the number of sectors in
the contiguous data area at the front.  This is mainly used by drivers
which transfers data by walking request segment-by-segment.  This
value always equals rq->bio->bi_size >> 9.  However, data length for
pc requests may not be multiple of 512 bytes and using this field
becomes a bit confusing.

In general, having multiple fields to represent the same property
leads only to confusion and subtle bugs.  With recent block low level
driver cleanups, no driver is accessing or manipulating these
duplicate fields directly.  Drop all the duplicates.  Now rq->sector
means the current sector, rq->data_len the current total length and
rq->bio->bi_size the current segment length.  Everything else is
defined in terms of these three and available only through accessors.

* blk_recalc_rq_sectors() is collapsed into blk_update_request() and
  now handles pc and fs requests equally other than rq->sector update.
  This means that now pc requests can use partial completion too (no
  in-kernel user yet tho).

* bio_cur_sectors() is replaced with bio_cur_bytes() as block layer
  now uses byte count as the primary data length.

* blk_rq_pos() is now guranteed to be always correct.  In-block users
  converted.

* blk_rq_bytes() is now guaranteed to be always valid as is
  blk_rq_sectors().  In-block users converted.

* blk_rq_sectors() is now guaranteed to equal blk_rq_bytes() >> 9.
  More convenient one is used.

* blk_rq_bytes() and blk_rq_cur_bytes() are now inlined and take const
  pointer to request.

[ Impact: API cleanup, single way to represent one property of a request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:54 +02:00
Tejun Heo
5b93629b45 block: implement blk_rq_pos/[cur_]sectors() and convert obvious ones
Implement accessors - blk_rq_pos(), blk_rq_sectors() and
blk_rq_cur_sectors() which return rq->hard_sector, rq->hard_nr_sectors
and rq->hard_cur_sectors respectively and convert direct references of
the said fields to the accessors.

This is in preparation of request data length handling cleanup.

Geert	: suggested adding const to struct request * parameter to accessors
Sergei	: spotted error in patch description

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Ackec-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:53 +02:00
Tejun Heo
c3a4d78c58 block: add rq->resid_len
rq->data_len served two purposes - the length of data buffer on issue
and the residual count on completion.  This duality creates some
headaches.

First of all, block layer and low level drivers can't really determine
what rq->data_len contains while a request is executing.  It could be
the total request length or it coulde be anything else one of the
lower layers is using to keep track of residual count.  This
complicates things because blk_rq_bytes() and thus
[__]blk_end_request_all() relies on rq->data_len for PC commands.
Drivers which want to report residual count should first cache the
total request length, update rq->data_len and then complete the
request with the cached data length.

Secondly, it makes requests default to reporting full residual count,
ie. reporting that no data transfer occurred.  The residual count is
an exception not the norm; however, the driver should clear
rq->data_len to zero to signify the normal cases while leaving it
alone means no data transfer occurred at all.  This reverse default
behavior complicates code unnecessarily and renders block PC on some
drivers (ide-tape/floppy) unuseable.

This patch adds rq->resid_len which is used only for residual count.

While at it, remove now unnecessasry blk_rq_bytes() caching in
ide_pc_intr() as rq->data_len is not changed anymore.

Boaz	: spotted missing conversion in osd
Sergei	: spotted too early conversion to blk_rq_bytes() in ide-tape

[ Impact: cleanup residual count handling, report 0 resid by default ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Borislav Petkov <petkovbb@googlemail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Doug Gilbert <dgilbert@interlog.com>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Eric Moore <Eric.Moore@lsi.com>
Cc: Darrick J. Wong <djwong@us.ibm.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-05-11 09:50:53 +02:00
Linus Torvalds
7b39da786a Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6:
  ide-cd: fix REQ_QUIET tests in cdrom_decode_status

Fix up trivial conflicts in include/linux/blkdev.h
2009-05-02 16:48:32 -07:00
Borislav Petkov
96c1674397 ide-cd: fix REQ_QUIET tests in cdrom_decode_status
Original patch (dfa4411cc3) was buggy.
This is a more proper fix which introduces blk_rq_quiet() macro
alleviating the need for dumb, too short caching variables.

Thanks to Helge Deller and Bart for debugging this.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Reported-and-tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-04-30 18:24:34 +02:00
Tejun Heo
9fd8d0e1bc block: make blk_end_request_cur() return bool
In the process of mindlessly copying [__]blk_end_request_all(),
[__]blk_end_request_cur() ended up returning void even though they're
partial completion functions.  Fix it.

[ Impact: fix braindead API ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-28 08:14:49 +02:00
Tejun Heo
731ec497e5 block: kill rq->data
Now that all block request data transfer is done via bio, rq->data
isn't used.  Kill it.

While at it, make the roles of rq->special and buffer clear.

[ Impact: drop now unncessary field from struct request ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Boaz Harrosh <bharrosh@panasas.com>
2009-04-28 07:37:36 +02:00
Tejun Heo
f06d9a2b52 block: replace end_request() with [__]blk_end_request_cur()
end_request() has been kept around for backward compatibility;
however, it's about time for it to go away.

* There aren't too many users left.

* Its use of @updtodate is pretty confusing.

* In some cases, newer code ends up using mixture of end_request() and
  [__]blk_end_request[_all](), which is way too confusing.

So, add [__]blk_end_request_cur() and replace end_request() with it.
Most conversions are straightforward.  Noteworthy ones are...

* paride/pcd: next_request() updated to take 0/-errno instead of 1/0.

* paride/pf: pf_end_request() and next_request() updated to take
  0/-errno instead of 1/0.

* xd: xd_readwrite() updated to return 0/-errno instead of 1/0.

* mtd/mtd_blkdevs: blktrans_discard_request() updated to return
  0/-errno instead of 1/0.  Unnecessary local variable res
  initialization removed from mtd_blktrans_thread().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Joerg Dorchain <joerg@dorchain.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Laurent Vivier <Laurent@lvivier.info>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: unsik Kim <donari75@gmail.com>
2009-04-28 07:37:36 +02:00
Tejun Heo
40cbbb781d block: implement and use [__]blk_end_request_all()
There are many [__]blk_end_request() call sites which call it with
full request length and expect full completion.  Many of them ensure
that the request actually completes by doing BUG_ON() the return
value, which is awkward and error-prone.

This patch adds [__]blk_end_request_all() which takes @rq and @error
and fully completes the request.  BUG_ON() is added to to ensure that
this actually happens.

Most conversions are simple but there are a few noteworthy ones.

* cdrom/viocd: viocd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/block/dasd: dasd_end_request() replaced with direct calls to
  __blk_end_request_all().

* s390/char/tape_block: tapeblock_end_request() replaced with direct
  calls to blk_end_request_all().

[ Impact: cleanup ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mike Miller <mike.miller@hp.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
2009-04-28 07:37:35 +02:00
Tejun Heo
2e60e02297 block: clean up request completion API
Request completion has gone through several changes and became a bit
messy over the time.  Clean it up.

1. end_that_request_data() is a thin wrapper around
   end_that_request_data_first() which checks whether bio is NULL
   before doing anything and handles bidi completion.
   blk_update_request() is a thin wrapper around
   end_that_request_data() which clears nr_sectors on the last
   iteration but doesn't use the bidi completion.

   Clean it up by moving the initial bio NULL check and nr_sectors
   clearing on the last iteration into end_that_request_data() and
   renaming it to blk_update_request(), which makes blk_end_io() the
   only user of end_that_request_data().  Collapse
   end_that_request_data() into blk_end_io().

2. There are four visible completion variants - blk_end_request(),
   __blk_end_request(), blk_end_bidi_request() and end_request().
   blk_end_request() and blk_end_bidi_request() uses blk_end_request()
   as the backend but __blk_end_request() and end_request() use
   separate implementation in __blk_end_request() due to different
   locking rules.

   blk_end_bidi_request() is identical to blk_end_io().  Collapse
   blk_end_io() into blk_end_bidi_request(), separate out request
   update into internal helper blk_update_bidi_request() and add
   __blk_end_bidi_request().  Redefine [__]blk_end_request() as thin
   inline wrappers around [__]blk_end_bidi_request().

3. As the whole request issue/completion usages are about to be
   modified and audited, it's a good chance to convert completion
   functions return bool which better indicates the intended meaning
   of return values.

4. The function name end_that_request_last() is from the days when it
   was a public interface and slighly confusing.  Give it a proper
   internal name - blk_finish_request().

5. Add description explaning that blk_end_bidi_request() can be safely
   used for uni requests as suggested by Boaz Harrosh.

The only visible behavior change is from #1.  nr_sectors counts are
cleared after the final iteration no matter which function is used to
complete the request.  I couldn't find any place where the code
assumes those nr_sectors counters contain the values for the last
segment and this change is good as it makes the API much more
consistent as the end result is now same whether a request is
completed using [__]blk_end_request() alone or in combination with
blk_update_request().

API further cleaned up per Christoph's suggestion.

[ Impact: cleanup, rq->*nr_sectors always updated after req completion ]

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Boaz Harrosh <bharrosh@panasas.com>
Cc: Christoph Hellwig <hch@infradead.org>
2009-04-28 07:37:35 +02:00
Tejun Heo
0b302d5aa7 block: kill blk_end_request_callback()
With recent IDE updates, blk_end_request_callback() doesn't have any
user now.  Kill it.

[ Impact: removal of unused convoluted interface ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
5efccd17ce block: reorder request completion functions
Reorder request completion functions such that

* All request completion functions are located together.

* Functions which are used by only one caller is put right above the
  caller.

* end_request() is put after other completion functions but before
  blk_update_request().

This change is for completion function cleanup which will follow.

[ Impact: cleanup, code reorganization ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:34 +02:00
Tejun Heo
a7f5579234 block: kill blk_start_queueing()
blk_start_queueing() is identical to __blk_run_queue() except that it
doesn't check for recursion.  None of the current users depends on
blk_start_queueing() running request_fn directly.  Replace usages of
blk_start_queueing() with [__]blk_run_queue() and kill it.

[ Impact: removal of mostly duplicate interface function ]

Signed-off-by: Tejun Heo <tj@kernel.org>
2009-04-28 07:37:33 +02:00
Jerome Marchand
42dad7647a block: simplify I/O stat accounting
This simplifies I/O stat accounting switching code and separates it
completely from I/O scheduler switch code.

Requests are accounted according to the state of their request queue
at the time of the request allocation. There is no need anymore to
flush the request queue when switching I/O accounting state.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-24 08:54:21 +02:00
Jens Axboe
2385327725 block: remove unused REQ_UNPLUG
The request inherits the unplug flag from the bio, but it isn't actually
used. The bio flag stops at __make_request(), which tells it to unplug
after submission. Passing it on to the request doesn't make any sense.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-04-07 08:59:11 +02:00
Jens Axboe
aeb6fafb8f block: Add flag for telling the IO schedulers NOT to anticipate more IO
By default, CFQ will anticipate more IO from a given io context if the
previously completed IO was sync. This used to be fine, since the only
sync IO was reads and O_DIRECT writes. But with more "normal" sync writes
being used now, we don't want to anticipate for those.

Add a bio/request flag that informs the IO scheduler that this is a sync
request that we should not idle for. Introduce WRITE_ODIRECT specifically
for O_DIRECT writes, and make sure that the other sync writes set this
flag.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06 08:04:54 -07:00
Jens Axboe
1faa16d228 block: change the request allocation/congestion logic to be sync/async based
This makes sure that we never wait on async IO for sync requests, instead
of doing the split on writes vs reads.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-06 08:04:53 -07:00
Jens Axboe
1e42807918 block: reduce stack footprint of blk_recount_segments()
blk_recalc_rq_segments() requires a request structure passed in, which
we don't have from blk_recount_segments(). So the latter allocates one on
the stack, using > 400 bytes of stack for that. This can cause us to spill
over one page of stack from ext4 at least:

 0)     4560     400   blk_recount_segments+0x43/0x62
 1)     4160      32   bio_phys_segments+0x1c/0x24
 2)     4128      32   blk_rq_bio_prep+0x2a/0xf9
 3)     4096      32   init_request_from_bio+0xf9/0xfe
 4)     4064     112   __make_request+0x33c/0x3f6
 5)     3952     144   generic_make_request+0x2d1/0x321
 6)     3808      64   submit_bio+0xb9/0xc3
 7)     3744      48   submit_bh+0xea/0x10e
 8)     3696     368   ext4_mb_init_cache+0x257/0xa6a [ext4]
 9)     3328     288   ext4_mb_regular_allocator+0x421/0xcd9 [ext4]
10)     3040     160   ext4_mb_new_blocks+0x211/0x4b4 [ext4]
11)     2880     336   ext4_ext_get_blocks+0xb61/0xd45 [ext4]
12)     2544      96   ext4_get_blocks_wrap+0xf2/0x200 [ext4]
13)     2448      80   ext4_da_get_block_write+0x6e/0x16b [ext4]
14)     2368     352   mpage_da_map_blocks+0x7e/0x4b3 [ext4]
15)     2016     352   ext4_da_writepages+0x2ce/0x43c [ext4]
16)     1664      32   do_writepages+0x2d/0x3c
17)     1632     144   __writeback_single_inode+0x162/0x2cd
18)     1488      96   generic_sync_sb_inodes+0x1e3/0x32b
19)     1392      16   sync_sb_inodes+0xe/0x10
20)     1376      48   writeback_inodes+0x69/0xb3
21)     1328     208   balance_dirty_pages_ratelimited_nr+0x187/0x2f9
22)     1120     224   generic_file_buffered_write+0x1d4/0x2c4
23)      896     176   __generic_file_aio_write_nolock+0x35f/0x393
24)      720      80   generic_file_aio_write+0x6c/0xc8
25)      640      80   ext4_file_write+0xa9/0x137 [ext4]
26)      560     320   do_sync_write+0xf0/0x137
27)      240      48   vfs_write+0xb3/0x13c
28)      192      64   sys_write+0x4c/0x74
29)      128     128   system_call_fastpath+0x16/0x1b

Split the segment counting out into a __blk_recalc_rq_segments() helper
to avoid allocating an onstack request just for checking the physical
segment count.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-26 10:45:48 +01:00
Jens Axboe
0648e10d71 block: fix inconsistent parenthesisation of QUEUE_FLAG_DEFAULT
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-02-02 08:43:48 +01:00
Jens Axboe
bc58ba9468 block: add sysfs file for controlling io stats accounting
This allows us to turn off disk stat accounting completely, for the cases
where the 0.5-1% reduction in system time is important.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-01-30 12:34:38 +01:00