linux-toradex.git/block/blk-barrier.c, branch v2.6.34.9

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

2010-03-30T13:02:32+00:00

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.

Signed-off-by: Tejun Heo 
Guess-its-ok-by: Christoph Lameter 
Cc: Ingo Molnar 
Cc: Lee Schermerhorn

block: Honor the gfp_mask for alloc_page() in blkdev_issue_discard()

2009-12-29T07:53:54+00:00

Signed-off-by: OGAWA Hirofumi 
Signed-off-by: Jens Axboe

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