linux.git/drivers/block/xd.c, branch v2.6.33

block,xd: Delay allocation of DMA buffers until device is known

2009-12-09T14:11:03+00:00

Loading the XD module triggers a warning like

 WARNING: at mm/page_alloc.c:1805
 __alloc_pages_nodemask+0x127/0x48f()
 Hardware name: System Product Name
 Modules linked in:
 Pid: 1, comm: swapper Not tainted 2.6.32-rc8-git5 #1
 Call Trace:
  [] warn_slowpath_common+0x65/0x95
  [] warn_slowpath_null+0x12/0x15
  [] __alloc_pages_nodemask+0x127/0x48f
  [] ? get_slab+0x8/0x50
  [] alloc_page_interleave+0x2e/0x6e
  [] alloc_pages_current+0x57/0x99
  [] ? xd_init+0x0/0x482
  [] __get_free_pages+0xd/0x1e
  [] xd_init+0x4a/0x482
  [] ? loop_init+0x104/0x16a
  [] ? loop_probe+0x0/0xaf
  [] ? xd_init+0x0/0x482
  [] do_one_initcall+0x51/0x13f
  [] kernel_init+0x10b/0x15f
  [] ? kernel_init+0x0/0x15f
  [] kernel_thread_helper+0x7/0x10
 ---[ end trace 686db6333ade6e7a ]---
 xd: Out of memory.

The warning is because the alloc_pages is called with an
order >= MAX_ORDER. The simplistic reason is that get_order(0) returns garbage
values when given 0 as a size. The more complex reason is that the XD driver
initialisation is broken.

It's not clear why this ever worked. XD allocates a buffer for DMA based
on the value of xd_maxsectors. This value is determined by the exact
type of controller in use but the value is determined *after* an attempt
has been made to allocate the buffer. i.e. the requested size of the DMA
buffer will always be 0.

This patch alters how XD is initialised slightly by allocating the
buffer when and if a device has actually been detected. The error paths
are updated to suit the new logic.

Signed-off-by: Mel Gorman 
Signed-off-by: Jens Axboe

const: make block_device_operations const

2009-09-22T14:17:25+00:00

Signed-off-by: Alexey Dobriyan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

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

xd: dequeue in-flight request

2009-05-11T07:52:16+00:00

xd processes requests one-by-one synchronously and can be easily
converted to dequeueing model.  Convert it.

While at it, use rq_cur_bytes instead of rq_bytes when checking for
sector overflow.  This is for for consistency and better behavior for
merged requests.

[ Impact: dequeue in-flight request ]

Signed-off-by: Tejun Heo 
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

amiflop,ataflop,xd,mg_disk: clean up unnecessary stuff from block drivers

2009-04-28T06:14:50+00:00

rq_data_dir() can only be READ or WRITE and rq->sector and nr_sectors
are always automatically updated after partial request completion.
Don't worry about rq_data_dir() not being either READ or WRITE or
manually update sector and nr_sectors.

[ Impact: cleanup ]

Signed-off-by: Tejun Heo 
Cc: Jörg Dorchain 
Cc: Geert Uytterhoeven 
Cc: unsik Kim 
Signed-off-by: Jens Axboe

block: replace end_request() with [__]blk_end_request_cur()

2009-04-28T05:37:36+00:00

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 
Acked-by: Joerg Dorchain 
Acked-by: Geert Uytterhoeven 
Acked-by: Grant Likely 
Acked-by: Laurent Vivier 
Cc: Tim Waugh 
Cc: Stephen Rothwell 
Cc: Paul Mackerras 
Cc: Jeremy Fitzhardinge 
Cc: Markus Lidel 
Cc: David Woodhouse 
Cc: Pete Zaitcev 
Cc: unsik Kim

[PATCH] switch xd

2008-10-21T11:48:11+00:00

Signed-off-by: Al Viro

[PATCH] beginning of methods conversion

2008-10-21T11:47:32+00:00

To keep the size of changesets sane we split the switch by drivers;
to keep the damn thing bisectable we do the following:
	1) rename the affected methods, add ones with correct
prototypes, make (few) callers handle both.  That's this changeset.
	2) for each driver convert to new methods.  *ALL* drivers
are converted in this series.
	3) kill the old (renamed) methods.

Note that it _is_ a flagday; all in-tree drivers are converted and by the
end of this series no trace of old methods remain.  The only reason why
we do that this way is to keep the damn thing bisectable and allow per-driver
debugging if anything goes wrong.

New methods:
	open(bdev, mode)
	release(disk, mode)
	ioctl(bdev, mode, cmd, arg)		/* Called without BKL */
	compat_ioctl(bdev, mode, cmd, arg)
	locked_ioctl(bdev, mode, cmd, arg)	/* Called with BKL, legacy */

Signed-off-by: Al Viro

[BLOCK] Get rid of request_queue_t typedef

2007-07-24T07:28:11+00:00

Some of the code has been gradually transitioned to using the proper
struct request_queue, but there's lots left. So do a full sweet of
the kernel and get rid of this typedef and replace its uses with
the proper type.

Signed-off-by: Jens Axboe