Impact: remove fields and code paths which are no longer necessary

Now that ide-tape uses standard mechanisms to transfer data, special
case handling for bh handling can be dropped from ide-atapi.  Drop the
followings.

* pc->cur_pos, b_count, bh and b_data
* drive->pc_update_buffers() and pc_io_buffers().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

idetape_chrdev_read/write() functions are unnecessarily complex when
everything can be handled in a single loop.  Collapse
idetape_add_chrdev_read/write_request() into the rw functions and
simplify the implementation.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

Byte size is what most issue functions deal with, make
idetape_queue_rw_tail() and its wrappers take byte size instead of
sector counts.  idetape_chrdev_read() and write() functions are
converted to use tape->buffer_size instead of ctl from tape->cap.

This cleans up code a little bit and will ease the next r/w
reimplementation.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup

Read and write init paths are almost identical.  Unify them into
idetape_init_rw().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: kill now unnecessary idetape_bh

With everything using standard mechanisms, there is no need for
idetape_bh anymore.  Kill it and use tape->buf, cur and valid to
describe data buffer instead.

Changes worth mentioning are...

* idetape_queue_rq_tail() now always queue tape->buf and and adjusts
  buffer state properly before completion.

* idetape_pad_zeros() clears the buffer only once.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: use standard way to transfer data

ide-tape uses rq in an interesting way.  For r/w requests, rq->special
is used to carry a private buffer management structure idetape_bh and
rq->nr_sectors and current_nr_sectors are initialized to the number of
idetape blocks which isn't necessary 512 bytes.  Also,
rq->current_nr_sectors is used to report back the residual count in
units of idetape blocks.

This peculiarity taxes both block layer and ide.  ide-atapi has
different paths and hooks to accomodate it and what a rq means becomes
quite confusing and making changes at the block layer becomes quite
difficult and error-prone.

This patch makes ide-tape use bio instead.  With the previous patch,
ide-tape currently is using single contiguos buffer so replacing it
isn't difficult.  Data buffer is mapped into bio using
blk_rq_map_kern() in idetape_queue_rw_tail().  idetape_io_buffers()
and idetape_update_buffers() are dropped and pc->bh is set to null to
tell ide-atapi to use standard data transfer mechanism and idetape_bh
byte counts are updated by the issuer on completion using the residual
count.

This change also nicely removes the FIXME in ide_pc_intr() where
ide-tape rqs need to be completed using ide_rq_bytes() instead of
blk_rq_bytes() (although this didn't really matter as the request
didn't have bio).
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>

Impact: simpler buffer allocation and handling, kills OOM, fix DMA transfers

ide-tape has its own multiple buffer mechanism using struct
idetape_bh.  It allocates buffer with decreasing order-of-two
allocations so that it results in minimum number of segments.
However, the implementation is quite complex and works in a way that
no other block or ide driver works necessitating a lot of special case
handling.

The benefit this complex allocation scheme brings is questionable as
PIO or DMA the number of segments (16 maximum) doesn't make any
noticeable difference and it also doesn't negate the need for multiple
order allocation which can fail under memory pressure or high
fragmentation although it does lower the highest order necessary by
one when the buffer size isn't power of two.

As the first step to remove the custom buffer management, this patch
makes ide-tape allocate single continous buffer.  The maximum order is
four.  I doubt the change would cause any trouble but if it ever
matters, it should be converted to regular sg mechanism like everyone
else and even in that case dropping custom buffer handling and moving
to standard mechanism first make sense as an intermediate step.

This patch makes the first bh to contain the whole buffer and drops
multi bh handling code.  Following patches will make further changes.

This patch has the side effect of killing OOM triggered by allocation
path and fixing DMA transfers.  Previously, bug in alloc path
triggered OOM on command issue and commands were passed to DMA engine
without DMA-mapping all the segments.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: allow residual count implementation in ->pc_callback()

rq->data_len has two duties - carrying the number of input bytes on
issue and carrying residual count back to the issuer on completion.
ide-atapi completion callback ->pc_callback() is the right place to do
this but currently ide-atapi depends on rq->data_len carrying the
original request size after calling ->pc_callback() to complete the pc
request.

This patch makes ide_pc_intr(), ide_tape_issue_pc() and
ide_floppy_issue_pc() cache length to complete before calling
->pc_callback() so that it can modify rq->data_len as necessary.

Note: As using rq->data_len for two purposes can make cases like this
      incorrect in subtle ways, future changes will introduce separate
      field for residual count.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <jens.axboe@oracle.com>

Impact: fix infinite retry loop

After a command failed, ide-tape and floppy inserts REQUEST_SENSE in
front of the failed command and according to the result, sets
pc->retries, flags and errors.  After REQUEST_SENSE is complete, the
failed command is again at the front of the queue and if the verdict
was to terminate the request, the issue functions tries to complete it
directly by calling drive->pc_callback() and returning ide_stopped.

However, drive->pc_callback() doesn't complete a request.  It only
prepares for completion of the request.  As a result, this creates an
infinite loop where the failed request is retried perpetually.

Fix it by actually ending the request by calling ide_complete_rq().
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: cleanup rq->data usage

ide-pm uses rq->data to carry pointer to struct request_pm_state
through request queue and rq->special is used to carray pointer to
local struct ide_cmd, which isn't necessary.  Use rq->special for
request_pm_state instead and use local ide_cmd in
ide_start_power_step().
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: unify request data buffer handling

rq->data is used mostly to pass kernel buffer through request queue
without using bio.  There are only a couple of places which still do
this in kernel and converting to bio isn't difficult.

This patch converts ide-cd and atapi to use bio instead of rq->data
for request sense and internal pc commands.  With previous change to
unify sense request handling, this is relatively easily achieved by
adding blk_rq_map_kern() during sense_rq prep and PC issue.

If blk_rq_map_kern() fails for sense, the error is deferred till sense
issue and aborts the failed command which triggered the sense.  Note
that this is a slim possibility as sense prep is done on each command
issue, so for the above condition to actually trigger, all preps since
the last sense issue till the issue of the request which would require
a sense should fail.

* do_request functions might sleep now.  This should be okay as ide
  request_fn - do_ide_request() - is invoked only from make_request
  and plug work.  Make sure this is the case by adding might_sleep()
  to do_ide_request().

* Functions which access the read sense data before the sense request
  is complete now should access bio_data(sense_rq->bio) as the sense
  buffer might have been copied during blk_rq_map_kern().

* ide-tape updated to map sg.

* cdrom_do_block_pc() now doesn't have to deal with REQ_TYPE_ATA_PC
  special case.  Simplified.

* tp_ops->output/input_data path dropped from ide_pc_intr().
Signed-off-by: Tejun Heo <tj@kernel.org>

Since we're issuing REQ_TYPE_SENSE now we need to allow those types of
rqs in the ->do_request callbacks. As a future improvement, sense_len
assignment might be unified across all ATAPI devices. Borislav to
check with specs and test.

As a result, get rid of ide_queue_pc_head() and
drive->request_sense_rq.

tj: * Init request sense ide_atapi_pc from sense request.  In the
      longer timer, it would probably better to fold
      ide_create_request_sense_cmd() into its only current user -
      ide_floppy_get_format_progress().

    * ide_retry_pc() no longer takes @disk.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Preallocate a sense request in the ->do_request method and reinitialize
it only on demand, in case it's been consumed in the IRQ handler path.
The reason for this is that we don't want to be mapping rq to bio in
the IRQ path and introduce all kinds of unnecessary hacks to the block
layer.

tj: * Both user and kernel PC requests expect sense data to be stored
      in separate storage other than drive->sense_data.  Copy sense
      data to rq->sense on completion if rq->sense is not NULL.  This
      fixes bogus sense data on PC requests.

As a result, remove cdrom_queue_request_sense.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

This is in preparation of removing the queueing of a sense request out
of the IRQ handler path.

Use struct request_sense as a general sense buffer for all ATAPI
devices ide-{floppy,tape,cd}.

tj: * blk_get_request(__GFP_WAIT) can't be called from do_request() as
      it can cause deadlock.  Converted to use inline struct request
      and blk_rq_init().

    * Added xfer / cdb len selection depending on device type.

    * All sense prep logics folded into ide_prep_sense() which never
      fails.

    * hwif->rq clearing and sense_rq used handling moved into
      ide_queue_sense_rq().

    * blk_rq_map_kern() conversion is moved to later patch.

CC: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
CC: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: rq->buffer usage cleanup

ide-cd uses rq->buffer to carry pointer to the original request when
issuing REQUEST_SENSE.  Use rq->special instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: rq->buffer usage cleanup

ide-atapi uses rq->buffer as private opaque value for internal special
requests.  rq->special isn't used for these cases (the only case where
rq->special is used is for ide-tape rw requests).  Use rq->special
instead.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: rq->buffer usage cleanup

ide_raw_taskfile() directly uses rq->buffer to carry pointer to the
data buffer.  This complicates both block interface and ide backend
request handling.  Use blk_rq_map_kern() instead and drop special
handling for REQ_TYPE_ATA_TASKFILE from ide_map_sg().

Note that REQ_RW setting is moved upwards as blk_rq_map_kern() uses it
to initialize bio rw flag.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: remove unnecessary code path

Block pc requests always use bio and rq->data is always NULL.  No need
to worry about !rq->bio cases in idefloppy_block_pc_cmd().  Note that
ide-atapi uses ide_pio_bytes() for bio PIO transfer which handle sg
fine.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>

Impact: code simplification

ide_cd_request_sense_fixup() clears the tail of the sense buffer if
the device didn't completely fill it.  This patch makes
cdrom_queue_request_sense() clear the sense buffer before issuing the
command instead of clearing it afterwards.  This simplifies code and
eases future changes.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: removal of unused field

No one uses ide_cmd->special anymore.  Kill it.
Signed-off-by: Tejun Heo <tj@kernel.org>

ide doesn't have to worry about REQ_SOFTBARRIER.  Don't set it.
Signed-off-by: Tejun Heo <tj@kernel.org>

blk_start_queueing() is being phased out in favor of
[__]blk_run_queue().  Switch.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: fix an oops which always triggers

ide_tape_issue_pc() assumed drive->pc isn't NULL on invocation when
checking for back-to-back request sense issues but drive->pc can be
NULL and even when it's not NULL, it's not safe to dereference it once
the previous command is complete because pc could have been freed or
was on stack.  Kill back-to-back REQUEST_SENSE detection.
Signed-off-by: Tejun Heo <tj@kernel.org>

Impact: subtle behavior change

For fs requests, rq is only carrier of bios and rq error status as a
whole doesn't mean much.  This is the reason why rq->errors is being
cleared on each partial completion of a request as on each partial
completion the error status is transferred to the respective bios.

For pc requests, rq->errors is used to carry error status to the
issuer and thus __end_that_request_first() doesn't clear it on such
cases.

The condition was fine till now as only fs and pc requests have used
bio and thus the bio completion path.  However, future changes will
unify data accesses to bio and all non fs users care about rq error
status.  Clear rq->errors on bio completion only for fs requests.

In general, the implicit clearing is a bit too subtle especially as
the meaning of rq->errors is completely dependent on low level
drivers.  Unifying / cleaning up rq->errors usage and letting llds
manage it would be better.  TODO comment added.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>

The driver somehow got merged with the initializer for the dma_sff_read_status()
method missing which caused kernel panic on bootup.

This should fix the kernel.org bug #13026...
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Reported-by: Arnd Hannemann <hannemann@nets.rwth-aachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Freeing non-slab objects is bad and results in an oops.  Fix it.
Reported-and-tested-by: Andrew Price <andy@andrewprice.me.uk>
Cc: Theodore Tso <tytso@mit.edu>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Remove uneeded void casts
Signed-off-by: Jack Stone <jwjstone@fastmail.fm>
Cc: jeff@garzik.org
Cc: kernel-janitors@vger.kernel.org
Cc: Jack Stone <jwjstone@fastmail.fm>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

Use ATA_DMA_* constants instead of the bare numbers for the BMIDE register bits.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

The big driver change in 2.4.19-rc1 introduced a regression for many HPT370[A]
chips -- DMA stopped to work completely, only causing endless timeouts...

The culprit has been identified (at last!): it turned to be the code resetting
the DMA state machine before each transfer. Stop doing it now as this counter-
measure has clearly caused more harm than good.

This should fix the kernel.org bug #7703.
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
  [libata] fix build error on drivers/ata/pata_legacy.c
  pata_via: Cache and rewrite the device bit
  sata_mv: workaround for multi_count errata sata24
  sata_mv: tidy up qc->tf usage in qc_prep() functions

fix those errors:

drivers/ata/pata_legacy.c: In function ‘pdc_data_xfer_vlb’:
drivers/ata/pata_legacy.c:289: error: ‘ap’ undeclared (first use in this function)
drivers/ata/pata_legacy.c:289: error: (Each undeclared identifier is reported only once
drivers/ata/pata_legacy.c:289: error: for each function it appears in.)
drivers/ata/pata_legacy.c: At top level:
drivers/ata/pata_legacy.c:869: error: ‘ATA_PFLAG_PIO32_CHANGE’ undeclared here (not in a
+function)
make[2]: *** [drivers/ata/pata_legacy.o] Error 1
make[1]: *** [drivers/ata] Error 2
Signed-off-by: Zhenwen Xu <helight.xu@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

Some VIA chipsets will reset the DEV bit after IEN changes on ctl. Our
optimised write path avoids doing this but we need to remove the
optimisation on these devices.

[Identified and some original patches proposed by Josehn Chan @ VIA but
discussion then all ground to a halt so given a test case I dug it back out]

Signed-off-by: Alan Cox <alan@lxorguk.ukuu.org.uk
Tested-by: Christoph Bisping (bug #13086)
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

Workaround for errata SATA#24 in sata_mv.
This errata affects WRITE_MULTI* commands when
the device multi_count produces a DRQ block size >= 4Kbytes.

We work around it here by converting such operations
into ordinary PIO_WRITEs instead.

Note that this might result in a PIO FUA write unavoidably being converted
into a non-FUA write.  In practice, any system using FUA is also going to be
using DMA rather than PIO, so this shouldn't affect anyone in the real world.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

Tidy up qc->tf accesses in the mv_qc_prep() functions.
Signed-off-by: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6: (43 commits)
  staging: slicoss: update README
  otus/zdusb.c: additional USB idnetifier
  Staging: go7007: fix build issues
  Staging: sxg: Fix leaks and checksum errors in transmit code path
  Staging: sxg: Fix sleep in atomic context warning while loading driver
  Staging: sxg: Use correct queue_id for transmitting non-TCP packets
  Staging: sxg: Fire watchdog timer at end of open routine to change the link
  Staging: Pohmelfs: Add load balancing between network states with the same priority.
  Staging: Pohmelfs: Added IO permissions and priorities.
  Staging: Pohmelfs: Added ->show_stats() callback.
  Staging: Pohmelfs: Drop ftrans debugging code.
  Staging: Pohmelfs: Use wait_on_page_timeout when waiting for remote directory sync instead of hardcoded 25 seconds.
  Staging: Pohmelfs: Reduce debugging noise about non-existing objects.
  Staging: Pohmelfs: Sync fs before killing it, since dentry cache is shrunk before writeback is invoked via generic_shutdown_super()
  Staging: Pohmelfs: Extend remount option.
  Staging: Pohmelfs: Set NETFS_INODE_REMOTE_SYNCED and clear NETFS_INODE_OWNED bits in the root inode.
  Staging: Pohmelfs: Added 'need_lock' variable into debug print.
  Staging: Pohmelfs: Disable read lock in pohmelfs_getattr().
  Staging: Pohmelfs: Move parent lock to the place where we really have to send a lookup request to the server.
  Staging: pohmelfs: Populate dentry cache when receiving the new readdir entry.
  ...

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core-2.6:
  UIO: fix specific device driver missing statement for depmod
  Driver core: remove pr_fmt() from dynamic_dev_dbg() printk
  driver core: prevent device_for_each_child from oopsing
  dynamic debug: resurrect old pr_debug() semantics as pr_devel()
  Driver Core: early platform driver
  proc: mounts_poll() make consistent to mdstat_poll
  sysfs: sysfs poll keep the poll rule of regular file.
  driver core: allow non-root users to listen to uevents
  driver core: fix driver_match_device
  sysfs: don't use global workqueue in sysfs_schedule_callback()

* git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (22 commits)
  WUSB: correct format of wusb_chid sysfs file
  WUSB: fix oops when completing URBs for disconnected devices
  WUSB: disconnect all devices when stopping a WUSB HCD
  USB: whci-hcd: check return value of usb_hcd_link_urb_to_ep()
  USB: whci-hcd: provide a endpoint_reset method
  USB: add reset endpoint operations
  USB device codes for Motorola phone.
  usb-storage: fix mistake in Makefile
  USB: usb-serial ch341: support for DTR/RTS/CTS
  Revert USB: usb-serial ch341: support for DTR/RTS/CTS
  USB: musb: fix possible panic while resuming
  USB: musb: fix isochronous TXDMA (take 2)
  USB: musb: sanitize clearing TXCSR DMA bits (take 2)
  USB: musb: bugfixes for multi-packet TXDMA support
  USB: musb_host, fix ep0 fifo flushing
  USB: usb-storage: augment unusual_devs entry for Simple Tech/Datafab
  USB: musb_host, minor enqueue locking fix (v2)
  USB: fix oops in cdc-wdm in case of malformed descriptors
  USB: qcserial: Add extra device IDs
  USB: option: Add ids for D-Link DWM-652 3.5G modem
  ...

* master.kernel.org:/home/rmk/linux-2.6-arm: (48 commits)
  [ARM] S3C24XX: ADC: Check pending queue before freeing adc client
  [ARM] S3C: Fix ADC driver sparse warning
  [ARM] Osiris: Fix double initialisation in machine block
  [ARM] Anubis: Fix sparse warnings for items that should be static
  [ARM] JIVE: Fix sparse warnings about items which should be static
  [ARM] S3C: Fix sparse warning from missing 's3c_device_hwmon'
  [ARM] S3C24XX: Fix sparse error in gpiolib.c
  [ARM] 5455/1: Fix IRQ noise from VIC code
  [ARM] 5454/1: ep93xx_eth: fix sparse warnings
  [ARM] remove .gitignore from include/asm-arm
  Update MAINTAINERS
  mxc defconfig updates
  mx31ads: Mark as having full regulatoion constraints with 1133-EV1 board
  mx31ads: Depend on all the WM8350 core dependencies for WM1133-EV1 board
  Fix ifdef in plat-mxc/irc.c
  MX1ADS: remove I2C ifdefs
  qong: remove AIPS[12] mappings from machine-specific iotable
  mx31ads: imoux pins should be passed in as unsigned int
  MXC: remove orphan imx_init_uart() definition
  mx31: pin definition for csi
  ...