* Add locking where it was missing.

* Don't do a get_mtd_device in blktrans_open because it would lead to a
  deadlock; instead do that in add_mtd_blktrans_dev.

* Only free the mtd_blktrans_dev structure when the last user exits.

* Flush request queue on device removal.

* Track users, and call tr->release in del_mtd_blktrans_dev
  Due to that ->open and release aren't called more that once.

Now it is safe to call del_mtd_blktrans_dev while the device is still in use.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

This is the biggest change. To make hotplug possible, and this layer 
clean, the mtd_blktrans_dev now contains everything for a single mtd 
block translation device. Also removed some very old leftovers.
Signed-off-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

add_mtd_blktrans_dev() imposes a maximum of 257 devices per block
translator.  This was presumably meant to prevent overflow back in the
days of 8-bit minor numbers.  Instead, check against MINORMASK and the
limits of the partition naming scheme.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Non MM subsystem must not use PF_MEMALLOC. Memory reclaim need few
memory, anyone must not prevent it. Otherwise the system cause
mysterious hang-up and/or OOM Killer invokation.
Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Mtdblock driver doesn't call flush_dcache_page for pages in request.  So,
this causes problems on architectures where the icache doesn't fill from
the dcache or with dcache aliases.  The patch fixes this.

The ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE symbol was introduced to avoid
pointless empty cache-thrashing loops on architectures for which
flush_dcache_page() is a no-op.  Every architecture was provided with this
flush pages on architectires where ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE is
equal 1 or do nothing otherwise.

See "fix mtd_blkdevs problem with caches on some architectures" discussion
on LKML for more information.
Signed-off-by: NIlya Loginov <isloginov@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Peter Horton <phorton@bitbox.co.uk>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

In register_mtd_blktrans(), the symbol 'ret' is already declared
as an int at the start of the function.  The inner loop declaration
is unnecessary.  Quiets the following sparse warning:

  warning: symbol 'ret' shadows an earlier one
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

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 <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

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 <matthew@wil.cx>
which did the prepare_discard_fn but not the different payload allocation
yet.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nowadays MTD devices have to be "get" before they can be
used. This has to be done with 'get_mtd_device()'. The
'blktrans_open()' function did not do this and instead
used 'try_module_get()'. Fix this.

Since 'get_mtd_device()' already gets the module, extra
'try_module_get()' is not needed.

This fixes oops when one tries to use mtdblock on top of
gluebi.
Reported-by: NHolger Brunck <holger.brunck@keymile.com>
Signed-off-by: NArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

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: NMartin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

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: NTejun 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: NJens Axboe <jens.axboe@oracle.com>

mtd_blkdevs processes requests one-by-one synchronously from a kthread
and can be easily converted to dequeueing model.  Convert it.

[ Impact: dequeue in-flight request ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

With the previous changes, the followings are now guaranteed for all
requests in any valid state.

* blk_rq_sectors() == blk_rq_bytes() >> 9
* blk_rq_cur_sectors() == blk_rq_cur_bytes() >> 9

Clean up accessor usages.  Notable changes are

* nbd,i2o_block: end_all used instead of explicit byte count
* scsi_lib: unnecessary conditional on request type removed

[ Impact: cleanup ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

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: NTejun Heo <tj@kernel.org>
Acked-by: NGeert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Tested-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Tested-by: NAdrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: NAdrian McMenamin <adrian@mcmen.demon.co.uk>
Acked-by: NMike Miller <mike.miller@hp.com>
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: Eric Moore <Eric.Moore@lsi.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Cc: Pete Zaitcev <zaitcev@redhat.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Clements <paul.clements@steeleye.com>
Cc: Tim Waugh <tim@cyberelk.net>
Cc: Jeff Garzik <jgarzik@pobox.com>
Cc: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Dario Ballabio <ballabio_dario@emc.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: unsik Kim <donari75@gmail.com>
Cc: Laurent Vivier <Laurent@lvivier.info>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

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: NTejun Heo <tj@kernel.org>
Acked-by: NJoerg Dorchain <joerg@dorchain.net>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NGrant Likely <grant.likely@secretlab.ca>
Acked-by: NLaurent 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>

Update driver model support in the MTD framework, so it fits
better into the current udev-based hotplug framework:

 - Each mtd_info now has a device node.  MTD drivers should set
   the dev.parent field to point to the physical device, before
   setting up partitions or otherwise declaring MTDs.

 - Those device nodes always map to /sys/class/mtdX device nodes,
   which no longer depend on MTD_CHARDEV.

 - Those mtdX sysfs nodes have a "starter set" of attributes;
   it's not yet sufficient to replace /proc/mtd.

 - Enabling MTD_CHARDEV provides /sys/class/mtdXro/ nodes and the
   /sys/class/mtd*/dev attributes (for udev, mdev, etc).

 - Include a MODULE_ALIAS_CHARDEV_MAJOR macro.  It'll work with
   udev creating the /dev/mtd* nodes, not just a static rootfs.

So the sysfs structure is pretty much what you'd expect, except
that readonly chardev nodes are a bit quirky.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Reported-by: NDan Carpenter <error27@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: NMarcin Slusarz <marcin.slusarz@gmail.com>
Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Janitorial work to remove temporary pointers and make some functions a bit
more readable.
Signed-off-by: NChris Malley <mail@chrismalley.co.uk>
Reviewed-By: NJörn Engel <joern@logfs.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Once upon a time, the MTD repository was using CVS.

This patch therefore removes all usages of the no longer updated CVS
keywords from the MTD code.

This also includes code that printed them to the user.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

We were only initialising the mutex in the case where the new device was
automatically allocated the highest minor number. If the caller
specified a minor number, or if it filled in a free slot which was made
by a previous device deregistering, the mutex wouldn't get initialised
when we jumped out of the loop.

Reported by Monte Copeland <catboat@texas.net>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NNigel Cunningham <nigel@nigel.suspend2.net>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix the sparse warnings generated by the implicit
dependency of mtd_blkdevs.c and mtd_core.c for the
two symbols mtd_table and mtd_table_mutex. This is
done by adding an local header file mtdcore.h to
define these (including the warning about the
non-proliferation of these symbols).
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

The mtd_blktrans_ops is not defined in any of the headers
and is indeed not used elsewhere in the kernel, so mark it
as static to reduce the warnings from sparse

drivers/mtd/mtd_blkdevs.c:204:32: warning: symbol 'mtd_blktrans_ops' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Ingo Molnar's semaphore to mutex conversions left some noise on a few
trylock calls. Clean it up.
Signed-off-by: NJean Delvare <khali@linux-fr.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove waitqueue, 'exiting' flag and completion; use kthread APIs instead.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

thread_run is used intead of kernel_thread, daemonize, and mucking
around blocking signals directly.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Signed-off-by: NYan Burman <yan_952@hotmail.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Currently, mtd_blkdevs enforces a block size of 512, even if the drivers
can seemingly request a different size. This patch fixes mtd_blkdevs so
block sizes other than 512 work correctly.
Signed-off-by: NRichard Purdie <rpurdie@openedhand.com>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

gcc spits out this warning:

drivers/mtd/mtd_blkdevs.c: In function ‘do_blktrans_request’:
drivers/mtd/mtd_blkdevs.c:72: warning: format ‘%ld’ expects type ‘long int’, but argument 2 has type ‘unsigned int’

This could be fixed any number of ways, including use of BUG().
rq_data_dir() only returns 0 or 1, so this entire case is superfluous.
I did the most simple fix.
Signed-off-by: NJeff Garzik <jeff@garzik.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Right now ->flags is a bit of a mess: some are request types, and
others are just modifiers. Clean this up by splitting it into
->cmd_type and ->cmd_flags. This allows introduction of generic
Linux block message types, useful for sending generic Linux commands
to block devices.
Signed-off-by: NJens Axboe <axboe@suse.de>

This reverts commit 668040fc.

The 'flags' field of the struct request is 'unsigned long'. Quite
how Randy came to see 'long int format, different type arg' I don't
know, but it doesn't seem to be the case any more.
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Fix printk format warning(s):
drivers/mtd/mtd_blkdevs.c:72: warning: long int format, different type arg (arg 2)
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NDavid Woodhouse <dwmw2@infradead.org>

Semaphore to mutex conversion.

The conversion was generated via scripts, and the result was validated
automatically via a script as well.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: NDavid Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

this changes if() BUG(); constructs to BUG_ON() which is
cleaner, contains unlikely() and can better optimized away.
Signed-off-by: NEric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>