linux-toradex.git/block/blk-barrier.c, branch v2.6.32.26

block: allow large discard requests

2009-10-01T19:19:34+00:00

Currently we set the bio size to the byte equivalent of the blocks to
be trimmed when submitting the initial DISCARD ioctl.  That means it
is subject to the max_hw_sectors limitation of the HBA which is
much lower than the size of a DISCARD request we can support.
Add a separate max_discard_sectors tunable to limit the size for discard
requests.

We limit the max discard request size in bytes to 32bit as that is the
limit for bio->bi_size.  This could be much larger if we had a way to pass
that information through the block layer.

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

block: use normal I/O path for discard requests

2009-10-01T19:19:30+00:00

prepare_discard_fn() was being called in a place where memory allocation
was effectively impossible.  This makes it inappropriate for all but
the most trivial translations of Linux's DISCARD operation to the block
command set.  Additionally adding a payload there makes the ownership
of the bio backing unclear as it's now allocated by the device driver
and not the submitter as usual.

It is replaced with QUEUE_FLAG_DISCARD which is used to indicate whether
the queue supports discard operations or not.  blkdev_issue_discard now
allocates a one-page, sector-length payload which is the right thing
for the common ATA and SCSI implementations.

The mtd implementation of prepare_discard_fn() is replaced with simply
checking for the request being a discard.

Largely based on a previous patch from Matthew Wilcox 
which did the prepare_discard_fn but not the different payload allocation
yet.

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

block: use blkdev_issue_discard in blk_ioctl_discard

2009-09-14T06:24:53+00:00

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 .

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

block: Use accessor functions for queue limits

2009-05-22T21:22:54+00:00

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 
Signed-off-by: Jens Axboe

block: change the tag sync vs async restriction logic

2009-05-20T06:54:31+00:00

Make them fully share the tag space, but disallow async requests using
the last any two slots.

Signed-off-by: Jens Axboe

block: implement and enforce request peek/start/fetch

2009-05-11T07:52:18+00:00

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 
Cc: Rusty Russell 
Cc: James Bottomley 
Cc: Mike Miller 
Cc: unsik Kim 
Cc: Paul Clements 
Cc: Tim Waugh 
Cc: Geert Uytterhoeven 
Cc: David S. Miller 
Cc: Laurent Vivier 
Cc: Jeff Garzik 
Cc: Jeremy Fitzhardinge 
Cc: Grant Likely 
Cc: Adrian McMenamin 
Cc: Stephen Rothwell 
Cc: Bartlomiej Zolnierkiewicz 
Cc: Borislav Petkov 
Cc: Sergei Shtylyov 
Cc: Alex Dubov 
Cc: Pierre Ossman 
Cc: David Woodhouse 
Cc: Markus Lidel 
Cc: Stefan Weinhuber 
Cc: Martin Schwidefsky 
Cc: Pete Zaitcev 
Cc: FUJITA Tomonori 
Signed-off-by: Jens Axboe

block: convert to pos and nr_sectors accessors

2009-05-11T07:50:54+00:00

With recent cleanups, there is no place where low level driver
directly manipulates request fields.  This means that the 'hard'
request fields always equal the !hard fields.  Convert all
rq->sectors, nr_sectors and current_nr_sectors references to
accessors.

While at it, drop superflous blk_rq_pos() < 0 test in swim.c.

[ Impact: use pos and nr_sectors accessors ]

Signed-off-by: Tejun Heo 
Acked-by: Geert Uytterhoeven 
Tested-by: Grant Likely 
Acked-by: Grant Likely 
Tested-by: Adrian McMenamin 
Acked-by: Adrian McMenamin 
Acked-by: Mike Miller 
Cc: James Bottomley 
Cc: Bartlomiej Zolnierkiewicz 
Cc: Borislav Petkov 
Cc: Sergei Shtylyov 
Cc: Eric Moore 
Cc: Alan Stern 
Cc: FUJITA Tomonori 
Cc: Pete Zaitcev 
Cc: Stephen Rothwell 
Cc: Paul Clements 
Cc: Tim Waugh 
Cc: Jeff Garzik 
Cc: Jeremy Fitzhardinge 
Cc: Alex Dubov 
Cc: David Woodhouse 
Cc: Martin Schwidefsky 
Cc: Dario Ballabio 
Cc: David S. Miller 
Cc: Rusty Russell 
Cc: unsik Kim 
Cc: Laurent Vivier 
Signed-off-by: Jens Axboe

block: implement blk_rq_pos/[cur_]sectors() and convert obvious ones

2009-05-11T07:50:53+00:00

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 
Acked-by: Geert Uytterhoeven 
Acked-by: Stephen Rothwell 
Tested-by: Grant Likely 
Acked-by: Grant Likely 
Ackec-by: Sergei Shtylyov 
Cc: Bartlomiej Zolnierkiewicz 
Cc: Borislav Petkov 
Cc: James Bottomley 
Signed-off-by: Jens Axboe

block: implement and use [__]blk_end_request_all()

2009-04-28T05:37:35+00:00

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 
Cc: Russell King 
Cc: Stephen Rothwell 
Cc: Mike Miller 
Cc: Martin Schwidefsky 
Cc: Jeff Garzik 
Cc: Rusty Russell 
Cc: Jeremy Fitzhardinge 
Cc: Alex Dubov 
Cc: James Bottomley

block: Remove code handling bio_alloc failure with __GFP_WAIT

2009-04-15T10:10:12+00:00

Remove code handling bio_alloc failure with __GFP_WAIT.
GFP_KERNEL implies __GFP_WAIT.

Signed-off-by: Nikanth Karthikesan 
Signed-off-by: Jens Axboe