Commit Graph

45 Commits

Author SHA1 Message Date
Tejun Heo
c995905916 block: fix diskstats access
There are two variants of stat functions - ones prefixed with double
underbars which don't care about preemption and ones without which
disable preemption before manipulating per-cpu counters.  It's unclear
whether the underbarred ones assume that preemtion is disabled on
entry as some callers don't do that.

This patch unifies diskstats access by implementing disk_stat_lock()
and disk_stat_unlock() which take care of both RCU (for partition
access) and preemption (for per-cpu counter access).  diskstats access
should always be enclosed between the two functions.  As such, there's
no need for the versions which disables preemption.  They're removed
and double underbars ones are renamed to drop the underbars.  As an
extra argument is added, there's no danger of using the old version
unconverted.

disk_stat_lock() uses get_cpu() and returns the cpu index and all
diskstat functions which access per-cpu counters now has @cpu
argument to help RT.

This change adds RCU or preemption operations at some places but also
collapses several preemption ops into one at others.  Overall, the
performance difference should be negligible as all involved ops are
very lightweight per-cpu ones.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:06 +02:00
Tejun Heo
e71bf0d0ee block: fix disk->part[] dereferencing race
disk->part[] is protected by its matching bdev's lock.  However,
non-critical accesses like collecting stats and printing out sysfs and
proc information used to be performed without any locking.  As
partitions can come and go dynamically, partitions can go away
underneath those non-critical accesses.  As some of those accesses are
writes, this theoretically can lead to silent corruption.

This patch fixes the race by using RCU for the partition array and dev
reference counter to hold partitions.

* Rename disk->part[] to disk->__part[] to make sure no one outside
  genhd layer proper accesses it directly.

* Use RCU for disk->__part[] dereferencing.

* Implement disk_{get|put}_part() which can be used to get and put
  partitions from gendisk respectively.

* Iterators are implemented to help iterate through all partitions
  safely.

* Functions which require RCU readlock are marked with _rcu suffix.

* Use disk_put_part() in __blkdev_put() instead of directly putting
  the contained kobject.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:06 +02:00
Tejun Heo
310a2c1012 block: misc updates
This patch makes the following misc updates in preparation for
disk->part dereference fix and extended block devt support.

* implment part_to_disk()

* fix comment about gendisk->part indexing

* rename get_part() to disk_map_sector()

* don't use n which is always zero while printing disk information in
  diskstats_show()

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:04 +02:00
Randy Dunlap
710027a48e Add some block/ source files to the kernel-api docbook. Fix kernel-doc notation in them as needed. Fix changed function parameter names. Fix typos/spellos. In comments, change REQ_SPECIAL to REQ_TYPE_SPECIAL and REQ_BLOCK_PC to REQ_TYPE_BLOCK_PC.
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:03 +02:00
Mikulas Patocka
5df97b91b5 drop vmerge accounting
Remove hw_segments field from struct bio and struct request. Without virtual
merge accounting they have no purpose.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:03 +02:00
David Woodhouse
e17fc0a1cc Allow elevators to sort/merge discard requests
But blkdev_issue_discard() still emits requests which are interpreted as
soft barriers, because naïve callers might otherwise issue subsequent
writes to those same sectors, which might cross on the queue (if they're
reallocated quickly enough).

Callers still _can_ issue non-barrier discard requests, but they have to
take care of queue ordering for themselves.

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:02 +02:00
David Woodhouse
fb2dce862d Add 'discard' request handling
Some block devices benefit from a hint that they can forget the contents
of certain sectors. Add basic support for this to the block core, along
with a 'blkdev_issue_discard()' helper function which issues such
requests.

The caller doesn't get to provide an end_io functio, since
blkdev_issue_discard() will automatically split the request up into
multiple bios if appropriate. Neither does the function wait for
completion -- it's expected that callers won't care about when, or even
_if_, the request completes. It's only a hint to the device anyway. By
definition, the file system doesn't _care_ about these sectors any more.

[With feedback from OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> and
Jens Axboe <jens.axboe@oracle.com]

Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:01 +02:00
David Woodhouse
d628eaef31 Fix up comments about matching flags between bio and rq
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:01 +02:00
Jens Axboe
051cc3952a block: use bio_has_data() in the IO completion path
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:00 +02:00
Jens Axboe
a9c701e594 block: use bio_has_data() to check for data carrying bio
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-09 08:56:00 +02:00
FUJITA Tomonori
abf5439370 block: move cmdfilter from gendisk to request_queue
cmd_filter works only for the block layer SG_IO with SCSI block
devices. It breaks scsi/sg.c, bsg, and the block layer SG_IO with SCSI
character devices (such as st). We hit a kernel crash with them.

The problem is that cmd_filter code accesses to gendisk (having struct
blk_scsi_cmd_filter) via inode->i_bdev->bd_disk. It works for only
SCSI block device files. With character device files, inode->i_bdev
leads you to struct cdev. inode->i_bdev->bd_disk->blk_scsi_cmd_filter
isn't safe.

SCSI ULDs don't expose gendisk; they keep it private. bsg needs to be
independent on any protocols. We shouldn't change ULDs to expose their
gendisk.

This patch moves struct blk_scsi_cmd_filter from gendisk to
request_queue, a common object, which eveyone can access to.

The user interface doesn't change; users can change the filters via
/sys/block/. gendisk has a pointer to request_queue so the cmd_filter
code accesses to struct blk_scsi_cmd_filter.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-27 09:50:19 +02:00
Jens Axboe
6c5e0c4d51 block: add a blk_plug_device_unlocked() that grabs the queue lock
blk_plug_device() must be called with the queue lock held, so callers
often just grab and release the lock for that purpose. Add a helper
that does just that.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-08-01 20:31:32 +02:00
Linus Torvalds
98339cbd36 Merge git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6
* git://git.kernel.org/pub/scm/linux/kernel/git/bart/ide-2.6: (80 commits)
  ide-floppy: fix unfortunate function naming
  ide-tape: unify idetape_create_read/write_cmd
  ide: add ide_pc_intr() helper
  ide-{floppy,scsi}: read Status Register before stopping DMA engine
  ide-scsi: add more debugging to idescsi_pc_intr()
  ide-scsi: use pc->callback
  ide-floppy: add more debugging to idefloppy_pc_intr()
  ide-tape: always log debug info in idetape_pc_intr() if debugging is enabled
  ide-tape: add ide_tape_io_buffers() helper
  ide-tape: factor out DSC handling from idetape_pc_intr()
  ide-{floppy,tape}: move checking of ->failed_pc to ->callback
  ide: add ide_issue_pc() helper
  ide: add PC_FLAG_DRQ_INTERRUPT pc flag
  ide-scsi: move idescsi_map_sg() call out from idescsi_issue_pc()
  ide: add ide_transfer_pc() helper
  ide-scsi: set drive->scsi flag for devices handled by the driver
  ide-{cd,floppy,tape}: remove checking for drive->scsi
  ide: add PC_FLAG_ZIP_DRIVE pc flag
  ide-tape: factor out waiting for good ireason from idetape_transfer_pc()
  ide-tape: set PC_FLAG_DMA_IN_PROGRESS flag in idetape_transfer_pc()
  ...
2008-07-15 11:15:36 -07:00
FUJITA Tomonori
52a93ba815 block: remove the checking for NULL queue in blk_put_request
Some uses blk_put_request asymmetrically, that is, they uses it with
requests that not allocated by blk_get_request. As a result,
blk_put_request has a hack to catch a NULL request_queue. Now such
callers are fixed (they use blk_get_request properly). So we can
safely remove the hack in blk_put_request.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-07-15 21:21:45 +02:00
Linus Torvalds
666484f025 Merge branch 'core/softirq' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core/softirq' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  softirq: remove irqs_disabled warning from local_bh_enable
  softirq: remove initialization of static per-cpu variable
  Remove argument from open_softirq which is always NULL
2008-07-14 15:28:42 -07:00
Jens Axboe
e48ec69005 block: extend queue_flag bitops
Add test_and_clear and test_and_set.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03 13:21:15 +02:00
Martin K. Petersen
7ba1ba12ee block: Block layer data integrity support
Some block devices support verifying the integrity of requests by way
of checksums or other protection information that is submitted along
with the I/O.

This patch implements support for generating and verifying integrity
metadata, as well as correctly merging, splitting and cloning bios and
requests that have this extra information attached.

See Documentation/block/data-integrity.txt for more information.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-07-03 13:21:13 +02:00
Ingo Molnar
9583f3d9c0 Merge branch 'linus' into core/softirq 2008-06-16 11:24:17 +02:00
Zhang, Yanmin
05caf8dbc1 block: Move the second call to get_request to the end of the loop
In function get_request_wait, the second call to get_request could be
moved to the end of the while loop, because if the first call to
get_request fails, the second call will fail without sleep.

Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-28 14:49:27 +02:00
Carlos R. Mafra
962cf36c5b Remove argument from open_softirq which is always NULL
As git-grep shows, open_softirq() is always called with the last argument
being NULL

block/blk-core.c:       open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
kernel/hrtimer.c:       open_softirq(HRTIMER_SOFTIRQ, run_hrtimer_softirq, NULL);
kernel/rcuclassic.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/rcupreempt.c:    open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL);
kernel/sched.c: open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
kernel/softirq.c:       open_softirq(TASKLET_SOFTIRQ, tasklet_action, NULL);
kernel/softirq.c:       open_softirq(HI_SOFTIRQ, tasklet_hi_action, NULL);
kernel/timer.c: open_softirq(TIMER_SOFTIRQ, run_timer_softirq, NULL);
net/core/dev.c: open_softirq(NET_TX_SOFTIRQ, net_tx_action, NULL);
net/core/dev.c: open_softirq(NET_RX_SOFTIRQ, net_rx_action, NULL);

This observation has already been made by Matthew Wilcox in June 2002
(http://www.cs.helsinki.fi/linux/linux-kernel/2002-25/0687.html)

"I notice that none of the current softirq routines use the data element
passed to them."

and the situation hasn't changed since them. So it appears we can safely
remove that extra argument to save 128 (54) bytes of kernel data (text).

Signed-off-by: Carlos R. Mafra <crmafra@ift.unesp.br>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-05-25 07:43:15 +02:00
Neil Brown
e7e72bf641 Remove blkdev warning triggered by using md
As setting and clearing queue flags now requires that we hold a spinlock
on the queue, and as blk_queue_stack_limits is called without that lock,
get the lock inside blk_queue_stack_limits.

For blk_queue_stack_limits to be able to find the right lock, each md
personality needs to set q->queue_lock to point to the appropriate lock.
Those personalities which didn't previously use a spin_lock, us
q->__queue_lock.  So always initialise that lock when allocated.

With this in place, setting/clearing of the QUEUE_FLAG_PLUGGED bit will no
longer cause warnings as it will be clear that the proper lock is held.

Thanks to Dan Williams for review and fixing the silly bugs.

Signed-off-by: NeilBrown <neilb@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Alistair John Strachan <alistair@devzero.co.uk>
Cc: Nick Piggin <npiggin@suse.de>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Jacek Luczak <difrost.kernel@gmail.com>
Cc: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-14 19:11:15 -07:00
Jens Axboe
28f13702f0 block: avoid duplicate calls to get_part() in disk stat code
get_part() is fairly expensive, as it O(N) loops over partitions
to find the right one. In lots of normal IO paths we end up looking
up the partition twice, to make matters even worse. Change the
stat add code to accept a passed in partition instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-07 10:15:46 +02:00
Jens Axboe
dbaf2c003e block: optimize generic_unplug_device()
Original patch from Mikulas Patocka <mpatocka@redhat.com>

Mike Anderson was doing an OLTP benchmark on a computer with 48 physical
disks mapped to one logical device via device mapper.

He found that there was a slowdown on request_queue->lock in function
generic_unplug_device. The slowdown is caused by the fact that when some
code calls unplug on the device mapper, device mapper calls unplug on all
physical disks. These unplug calls take the lock, find that the queue is
already unplugged, release the lock and exit.

With the below patch, performance of the benchmark was increased by 18%
(the whole OLTP application, not just block layer microbenchmarks).

So I'm submitting this patch for upstream. I think the patch is correct,
because when more threads call simultaneously plug and unplug, it is
unspecified, if the queue is or isn't plugged (so the patch can't make
this worse). And the caller that plugged the queue should unplug it
anyway. (if it doesn't, there's 3ms timeout).

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-05-07 09:48:17 +02:00
Harvey Harrison
24c03d47d0 block: remove remaining __FUNCTION__ occurrences
__FUNCTION__ is gcc specific, use __func__

Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-05-01 08:04:02 -07:00
FUJITA Tomonori
d7e3c3249e block: add large command support
This patch changes rq->cmd from the static array to a pointer to
support large commands.

We rarely handle large commands. So for optimization, a struct request
still has a static array for a command. rq_init sets rq->cmd pointer
to the static array.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29 14:48:55 +02:00
FUJITA Tomonori
d34c87e4ba block: replace sizeof(rq->cmd) with BLK_MAX_CDB
This is a preparation for changing rq->cmd from the static array to a
pointer.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29 14:48:55 +02:00
FUJITA Tomonori
2a4aa30c5f block: rename and export rq_init()
This rename rq_init() blk_rq_init() and export it. Any path that hands
the request to the block layer needs to call it to initialize the
request.

This is a preparation for large command support, which needs to
initialize the request in a proper way (that is, just doing a memset()
will not work).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29 14:48:55 +02:00
Nick Piggin
75ad23bc0f block: make queue flags non-atomic
We can save some atomic ops in the IO path, if we clearly define
the rules of how to modify the queue flags.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29 14:48:33 +02:00
FUJITA Tomonori
1afb20f301 block: make rq_init() do a full memset()
This requires moving rq_init() from get_request() to blk_alloc_request().
The upside is that we can now require an rq_init() from any path that
wishes to hand the request to the block layer.

rq_init() will be exported for the code that uses struct request
without blk_get_request.

This is a preparation for large command support, which needs to
initialize struct request in a proper way (that is, just doing a
memset() will not work).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-04-29 09:50:34 +02:00
Adrian Bunk
9d7f1e6b9b unexport blk_{get,put}_queue
This patch removes the unused exports of blk_{get,put}_queue.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-04 11:28:32 +01:00
FUJITA Tomonori
7a85f8896f block: restore the meaning of rq->data_len to the true data length
The meaning of rq->data_len was changed to the length of an allocated
buffer from the true data length. It breaks SG_IO friends and
bsg. This patch restores the meaning of rq->data_len to the true data
length and adds rq->extra_len to store an extended length (due to
drain buffer and padding).

This patch also removes the code to update bio in blk_rq_map_user
introduced by the commit 40b01b9bbd.
The commit adjusts bio according to memory alignment
(queue_dma_alignment). However, memory alignment is NOT padding
alignment. This adjustment also breaks SG_IO friends and bsg. Padding
alignment needs to be fixed in a proper way (by a separate patch).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
2008-03-04 11:17:11 +01:00
Randy Dunlap
5d87a052c7 block: fix kernel-docbook parameters and files
kernel-doc for block/:
- add missing parameters
- fix one function's parameter list (remove blank line)
- add 2 source files to docbook for non-exported kernel-doc functions

Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-03-04 11:14:39 +01:00
Tejun Heo
6b00769fe1 block: add request->raw_data_len
With padding and draining moved into it, block layer now may extend
requests as directed by queue parameters, so now a request has two
sizes - the original request size and the extended size which matches
the size of area pointed to by bios and later by sgs.  The latter size
is what lower layers are primarily interested in when allocating,
filling up DMA tables and setting up the controller.

Both padding and draining extend the data area to accomodate
controller characteristics.  As any controller which speaks SCSI can
handle underflows, feeding larger data area is safe.

So, this patch makes the primary data length field, request->data_len,
indicate the size of full data area and add a separate length field,
request->raw_data_len, for the unmodified request size.  The latter is
used to report to higher layer (userland) and where the original
request size should be fed to the controller or device.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-19 11:36:35 +01:00
Adrian Bunk
5ece6c52ea make blk-core.c:request_cachep static again
request_cachep needlessly became global.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Jens Axboe <axboe@carl.home.kernel.dk>
2008-02-19 10:04:00 +01:00
Jerome Marchand
c3c930d933 Enhanced partition statistics: remove old partition statistics
Removes the now unused old partition statistic code.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-08 12:42:01 +01:00
Jerome Marchand
6f2576af5b Enhanced partition statistics: update partition statitics
Updates the enhanced partition statistics in generic block layer
besides the disk statistics.

Signed-off-by: Jerome Marchand <jmarchan@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-08 12:41:56 +01:00
Jens Axboe
63a7138671 block: fixup rq_init() a bit
Rearrange fields in cache order and initialize some fields that
we didn't previously init. Remove init of ->completion_data, it's
part of a union with ->hash. Luckily clearing the rb node is the same
as setting it to null!

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-08 12:41:03 +01:00
Jens Axboe
6728cb0e63 block: make core bits checkpatch compliant
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-01 09:26:33 +01:00
Jens Axboe
22b132102f block: new end request handling interface should take unsigned byte counts
No point in passing signed integers as the byte count, they can never
be negative.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-02-01 09:26:33 +01:00
Jens Axboe
d6d4819696 block: ll_rw_blk.c split, add blk-merge.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:12 +01:00
Jens Axboe
db1d08c646 block: remove dated (and wrong) comment in blk-core.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:11 +01:00
Jens Axboe
26b8256e2b block: get rid of unnecessary forward declarations in blk-core.c
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:09 +01:00
Jens Axboe
86db1e2977 block: continue ll_rw_blk.c splitup
Adds files for barrier handling, rq execution, io context handling,
mapping data to requests, and queue settings.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:08 +01:00
Jens Axboe
8324aa91d1 block: split tag and sysfs handling from blk-core.c
Seperates the tag and sysfs handling from ll_rw_blk.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:07 +01:00
Jens Axboe
a168ee84c9 block: first step of splitting ll_rw_blk, rename it
Then we retain history in blk-core.c

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-01-29 21:55:05 +01:00