Both request functions in mg_disk simply return when they encounter a
!fs request, which means the request will never be cleared from the
queue causing queue hang and indefinite retry of the request.  Fix it.

While at it, flatten condition checks and add unlikely to !fs tests.

[ Impact: fix possible queue hang / infinite retry of !fs requests ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.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>

While at it:
- remove MG_REG_HEAD_MUST_BE_ON define
- remove MG_REG_CTRL_INTR_ENABLE define
- remove MG_REG_HEAD_LBA_MODE define
- remove unused defines

Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

Add local copies of ata_id_string() and ata_id_c_string() to mg_disk
so there is no need for the driver to depend on ATA and SCSI.

[ Impact: break dependency on libata by copying ata id string functions ]

Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

mg_disk implements its own partial completion.  Convert to standard
block layer partial completion.

[ Impact: cleanup ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

include/linux/mg_disk.h is used only by drivers/block/mg_disk.c.  No
reason to put it in a separate header.  Fold it into mg_disk.c.

[ Impact: cleanup ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

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: NTejun Heo <tj@kernel.org>
Cc: Jörg Dorchain <joerg@dorchain.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: unsik Kim <donari75@gmail.com>
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>

drivers/block/mg_disk.c: In function ‘mg_dump_status’:
drivers/block/mg_disk.c:265: warning: format ‘%ld’ expects type ‘long int’, but
argument 2 has type ‘sector_t’

[ Impact: kill build warning ]

Cc: unsik Kim <donari75@gmail.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

IRQ and timeout handlers call functions which expect locked queue lock
without locking it.  Fix it.

While at it, convert 0s used as null pointer constant to NULLs.

[ Impact: fix locking, cleanup ]
Signed-off-by: NTejun Heo <tj@kernel.org>
Cc: unsik Kim <donari75@gmail.com>

This driver supports mflash IO mode for linux.

Mflash is embedded flash drive and mainly targeted mobile and consumer
electronic devices.

Internally, mflash has nand flash and other hardware logics and supports 2
different operation (ATA, IO) modes.  ATA mode doesn't need any new driver
and currently works well under standard IDE subsystem.  Actually it's one
chip SSD.  IO mode is ATA-like custom mode for the host that doesn't have
IDE interface.

Followings are brief descriptions about IO mode.
A. IO mode based on ATA protocol and uses some custom command. (read confirm,
write confirm)
B. IO mode uses SRAM bus interface.
C. IO mode supports 4kB boot area, so host can boot from mflash.

This driver is quitely similar to a standard ATA driver, but because of
following reasons it is currently seperated with ATA layer.

1. ATA layer deals standard ATA protocol.  ATA layer have many low-
   level device specific interface, but data transfer keeps ATA rule.
   But, mflash IO mode doesn't.

2. Even though currently not used in mflash driver code, mflash has
   some custom command and modes.  (nand fusing, firmware patch, etc) If
   this feature supported in linux kernel, ATA layer more altered.

3. Currently PATA platform device driver doesn't support interrupt.
   (I'm not sure) But, mflash uses interrupt (polling mode is just for
   debug).

4. mflash is somewhat under-develop product.  Even though some company
   already using mflash their own product, I think more time is needed for
   standardization of custom command and mode.  That time (maybe October)
   I will talk to with ATA people.  If they accept integration, I will
   integrate.
Signed-off-by: Nunsik Kim <donari75@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>