Commit Graph

184 Commits

Author SHA1 Message Date
Bartlomiej Zolnierkiewicz
e354c1d803 ide: remove IDE_ARCH_LOCK (v2)
* Add ->{get,release}_lock methods to struct ide_port_info
  and struct ide_host.

* Convert core IDE code, m68k IDE code and falconide support to use
  ->{get,release}_lock methods instead of ide_{get,release}_lock().

* Remove IDE_ARCH_LOCK.

v2:
* Build fix from Geert updating ide_{get,release}_lock() callers in
  falconide.c.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michael Schmitz <schmitz@debian.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-27 12:46:22 +01:00
Bartlomiej Zolnierkiewicz
d15a613ba0 ide: remove IDE_ARCH_INTR (v2)
This micro-optimization is not worth it.  Just always check for
existence of ->ack_intr method in ide_intr() and ide_timer_expiry().

v2:
Fix brown-paper-bag bug spotted by David D. Kilzer.

Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Michael Schmitz <schmitz@debian.org>
Cc: "David D. Kilzer" <ddkilzer@kilzer.net>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-27 12:46:21 +01:00
Bartlomiej Zolnierkiewicz
327fa1c294 ide: move error handling code to ide-eh.c (v2)
Do some CodingStyle fixups in <linux/ide.h> while at it.

v2:
Add missing <linux/delay.h> include (reported by Stephen Rothwell).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:47 +01:00
Bartlomiej Zolnierkiewicz
11938c9290 ide: move device settings code to ide-devsets.c
Remove stale comment from ide.c while at it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:44 +01:00
Bartlomiej Zolnierkiewicz
c4e66c36cc ide: move ide_do_park_unpark() to ide-park.c
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:44 +01:00
Bartlomiej Zolnierkiewicz
1bc6daae4a ide: factor out processing of special commands from ide_special_rq()
Factor out processing of special commands from ide_special_rq()
to ide_do_devset() and ide_do_park_unpark().

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:44 +01:00
Bartlomiej Zolnierkiewicz
1866082339 ide: remove ide_do_drive_cmd()
* Use elv_add_request() instead of __elv_add_request() in ide_do_drive_cmd().

* ide_do_drive_cmd() is used only in ide-{atapi,cd}.c so inline it there.

There should be no functional changes caused by this patch.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:44 +01:00
Bartlomiej Zolnierkiewicz
65ca537732 ide: move ide_dma_timeout_retry() to ide-dma.c
Move ide_dma_timeout_retry() to ide-dma.c and add static inline
version for CONFIG_BLK_DEV_IDEDMA=n.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:43 +01:00
Bartlomiej Zolnierkiewicz
b6a45a0b1e ide: move drive_is_ready() to ide-io.c
Move drive_is_ready() to ide-io.c, then make it static.

Also make some minor CodingStyle fixups while at it.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:43 +01:00
Bartlomiej Zolnierkiewicz
75a0cff4e8 ide: unexport ide_devset_execute()
There are no modular ide_devset_execute() users left so unexport it.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:43 +01:00
Bartlomiej Zolnierkiewicz
7a254df007 ide: move ide_pktcmd_tf_load() to ide-atapi.c
Then make it static and remove 'dma' argument.

Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-24 23:22:39 +01:00
Stanislaw Gruszka
849d713000 ide: allow to wrap interrupt handler
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
Cc: Andrew Victor <linux@maxim.org.za>
[bart: minor checkpatch.pl / CodingStyle fixups]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-05 16:10:57 +01:00
Roel Kluin
e0c6dcd8d4 ide: expiry() returns int, negative expiry() return values won't be noticed
bart:
It seems like the bug could cause insanely long timeouts for:
- ATA_DMA_ERR error in dma_timer_expiry()
- commands without ->expiry in tc86c001_timer_expiry()
  (TC86C001 IDE controller only)

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
[bart: port it to the current tree]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-03-05 16:10:55 +01:00
Borislav Petkov
9e772d0135 ide-cd: fix DMA for non bio-backed requests
This one fixes http://bugzilla.kernel.org/show_bug.cgi?id=12320.

Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-02-02 20:12:21 +01:00
Bartlomiej Zolnierkiewicz
c38714ed44 ide: remove now redundant ->cur_dev checks
* ->cur_dev should now be always valid if ->handler is set so
  remove redundant checks from ide_intr() and ide_timer_expiry().

* Apply CodingStyle fixups in ide_timer_expiry() while at it.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:59 +01:00
Bartlomiej Zolnierkiewicz
b1b1cd9a23 ide: remove superfluous hwif variable assignment from ide_timer_expiry()
There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:58 +01:00
Bartlomiej Zolnierkiewicz
9600dcf134 ide: make "paranoia" ->handler check in ide_intr() more strict
If ->handler is set while it shouldn't be it indicates deep problems
so BUG_ON()-ning and preventing further damage is much more appropriate
than merely printing an error message.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:58 +01:00
Bartlomiej Zolnierkiewicz
627e05daa1 ide: remove ->error method from struct ide_driver
* Remove (now superfluous) ->error method from struct ide_driver.

* Unexport __ide_error() and make it static.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:54 +01:00
Bartlomiej Zolnierkiewicz
7f3c868ba7 ide: remove ide_driver_t typedef
While at it:
- s/struct ide_driver_s/struct ide_driver/
- use to_ide_driver() macro in ide-proc.c

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:53 +01:00
Bartlomiej Zolnierkiewicz
898ec223fe ide: remove HWIF() macro
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:52 +01:00
Bartlomiej Zolnierkiewicz
b65fac32cf ide: merge ide_hwgroup_t with ide_hwif_t (v2)
* Merge ide_hwgroup_t with ide_hwif_t.

* Cleanup init_irq() accordingly, then remove no longer needed
  ide_remove_port_from_hwgroup() and ide_ports[].

* Remove now unused HWGROUP() macro.

While at it:

* ide_dump_ata_error() fixups

v2:
* Fix ->quirk_list check in do_ide_request()
  (s/hwif->cur_dev/prev_port->cur_dev).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:50 +01:00
Bartlomiej Zolnierkiewicz
5b31f855f1 ide: use lock bitops for ports serialization (v2)
* Add ->host_busy field to struct ide_host and use it's first bit
  together with lock bitops to provide new ports serialization method.

* Convert core IDE code to use new ide_[un]lock_host() helpers.

  This removes the need for taking hwgroup->lock if host is already
  busy on serialized hosts and makes it possible to merge ide_hwgroup_t
  into ide_hwif_t (done in the later patch).

* Remove no longer needed ide_hwgroup_t.busy and ide_[un]lock_hwgroup().

* Update do_ide_request() documentation.

v2:
* ide_release_lock() should be called inside IDE_HFLAG_SERIALIZE check.

* Add ide_hwif_t.busy flag and ide_[un]lock_port() for serializing
  devices on a port.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:49 +01:00
Bartlomiej Zolnierkiewicz
efe0397eef ide: remove hwgroup->hwif and {drive,hwif}->next
* Add 'int port_count' field to ide_hwgroup_t to keep the track
  of the number of ports in the hwgroup.  Then update init_irq()
  and ide_remove_port_from_hwgroup() to use it.

* Remove no longer needed hwgroup->hwif, {drive,hwif}->next,
  ide_add_drive_to_hwgroup() and ide_remove_drive_from_hwgroup()
  (hwgroup->drive now only denotes the currently active device
   in the hwgroup).

* Update locking documentation in <linux/ide.h>.

While at it:

* Rename ->drive field in ide_hwgroup_t to ->cur_dev.

* Use __func__ in ide_timer_expiry().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:49 +01:00
Bartlomiej Zolnierkiewicz
ae86afaee6 ide: use per-port IRQ handlers
Use hwif instead of hwgroup as {request,free}_irq()'s cookie,
teach ide_intr() to return early for non-active serialized ports,
modify unexpected_intr() accordingly and then use per-port IRQ
handlers instead of per-hwgroup ones.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:48 +01:00
Bartlomiej Zolnierkiewicz
bd53cbcce5 ide: add ->cur_port to struct ide_host and use it for serialized hosts
* Pass 'ide_hwif_t *' instead of 'ide_hwgroup_t *' to unexpected_intr().

* Cache pointer to the port currently being serviced in ->cur_port
  and use it instead of hwif->hwgroup on serialized hosts.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:48 +01:00
Bartlomiej Zolnierkiewicz
42cf2611b2 ide: fix setting nIEN on idle devices
Fix do_ide_request() to operate on previous device / port instead of
the current one.  The original code was wrong since at least Feb 2002
(2.4.0 timeframe).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:47 +01:00
Bartlomiej Zolnierkiewicz
b46f205da6 ide: fix LOCKDEP warning
commit 295f00042a ("ide: don't execute
the next queued command from the hard-IRQ context") overlooked that
ide_do_drive_cmd() (used for REQUEST SENSE command handling) may still
invoke do_ide_request() (->request_fn) in the hard-IRQ context through
blk_start_queueing().  This resulted in a LOCKDEP warning after commit
b599bc7a1199419e122cb2e9ec6b0fa2cfbbc17b ("ide: use per-device request
queue locks (v2)").

Since calling blk_start_queuing() in ide_do_drive_cmd() doesn't make
much sense as the port is already marked as busy (so the execution of
the new command will be deferred anyway) then just remove it fixing
LOCKDEP warning and saving some CPU cycles at the same time.

Reported-and-tested-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Grissiom <chaos.proton@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-06 17:20:47 +01:00
Borislav Petkov
5317464dcc ide: remove the last ide-scsi remnants
Signed-off-by: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:54 +01:00
Bartlomiej Zolnierkiewicz
201bffa464 ide: use per-device request queue locks (v2)
* Move hack for flush requests from choose_drive() to do_ide_request().

* Add ide_plug_device() helper and convert core IDE code from using
  per-hwgroup lock as a request lock to use the ->queue_lock instead.

* Remove no longer needed:
  - choose_drive() function
  - WAKEUP() macro
  - 'sleeping' flag from ide_hwif_t
  - 'service_{start,time}' fields from ide_drive_t

This patch results in much simpler and more maintainable code
(besides being a scalability improvement).

v2:
* Fixes/improvements based on review from Elias:
  - take as many requests off the queue as possible
  - remove now redundant BUG_ON()

Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:50 +01:00
Bartlomiej Zolnierkiewicz
631de3708d ide: add ide_[un]lock_hwgroup() helpers
Add ide_[un]lock_hwgroup() inline helpers for obtaining exclusive
access to the given hwgroup and update the core code accordingly.

[ This change besides making code saner results in more efficient
  use of ide_{get,release}_lock(). ]

Cc: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:50 +01:00
Bartlomiej Zolnierkiewicz
b2cfb05a70 ide: remove "paranoia" checks for hwgroup->busy
Remove "paranoia" checks for hwgroup->busy from ide_timer_expiry()
and ide_intr().  This is a preparation for future changes.

Cc: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:49 +01:00
Bartlomiej Zolnierkiewicz
2fb211502e ide: remove IDE PM hack from do_ide_request()
We now tell block layer that there is still work to do using
blk_plug_device() so hack for IDE Power Management can be removed
(it was buggy for hwgroups having more than 4 devices anyway).

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:49 +01:00
Bartlomiej Zolnierkiewicz
295f00042a ide: don't execute the next queued command from the hard-IRQ context (v2)
* Tell the block layer that we are not done handling requests by using
  blk_plug_device() in ide_do_request() (request handling function)
  and ide_timer_expiry() (timeout handler) if the queue is not empty.

* Remove optimization which directly calls ide_do_request() for the next
  queued command from the ide_intr() (IRQ handler) and ide_timer_expiry().

* Remove no longer needed IRQ masking from ide_do_request() - in case of
  IDE ports needing serialization disable_irq_nosync()/enable_irq() was
  used for the (possibly shared) IRQ of the other IDE port.

* Put the misplaced comment in the right place in ide_do_request().

* Drop no longer needed 'int masked_irq' argument from ide_do_request().

* Merge ide_do_request() into do_ide_request().

* Remove no longer needed IDE_NO_IRQ define.

While at it:

* Don't use HWGROUP() macro in do_ide_request().

* Use __func__ in ide_intr().

This patch reduces IRQ hadling latency for IDE and improves the system-wide
handling of shared IRQs (which should result in more timeout resistant and
stable IDE systems).  It also makes it possible to do some further changes
later (i.e. replace some busy-waiting delays with sleeping equivalents).

v2:
Changes per review from Elias Oltmanns:
- fix wrong goto statement in 'if (startstop == ide_stopped)' block
- use spin_unlock_irq()
- don't use obsolete HWIF() macro

Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2009-01-02 16:12:48 +01:00
Bartlomiej Zolnierkiewicz
e2984c628c ide: move Power Management support to ide-pm.c
There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:37 +01:00
Bartlomiej Zolnierkiewicz
b002415012 ide: remove redundant code from ide_end_drive_cmd()
rq->errors is overwritten later in this function.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:36 +01:00
Bartlomiej Zolnierkiewicz
f58c1ab8de ide: always set nIEN on idle devices
* Set nIEN for previous port/device in ide_do_request()
  also if port uses a non-shared IRQ.

* Remove no longer needed ide_hwif_t.sharing_irq.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:33 +01:00
Bartlomiej Zolnierkiewicz
46aa7af1d6 ide: fix ->quirk_list checking in ide_do_request()
Fix nIEN quirk check to also omit quirky devices using pdc202xx_{new,old}
host drivers for which ->quirk_list == 2.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:33 +01:00
Bartlomiej Zolnierkiewicz
08cd1dca00 ide: cleanup ide_do_request()
Both choose_drive() and PM handling code make sure that the queue
is unplugged so no need to check it again.

Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:32 +01:00
Bartlomiej Zolnierkiewicz
2a2ca6a961 ide: replace the global ide_lock spinlock by per-hwgroup spinlocks (v2)
Now that (almost) all host drivers have been fixed not to abuse ide_lock
and core code usage of ide_lock has been sanitized we may safely replace
ide_lock by per-hwgroup locks.

This patch is partially based on earlier patch from Ravikiran G Thirumalai.

While at it:
- don't use deprecated HWIF() and HWGROUP() macros
- update locking documentation in ide.h

v2:
Add missing spin_lock_init(&hwgroup->lock).  (Noticed by Elias Oltmanns)

Cc: Vaibhav V. Nivargi <vaibhav.nivargi@gmail.com>
Cc: Alok N. Kataria <alokk@calsoftinc.com>
Cc: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Elias Oltmanns <eo@nebensachen.de>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:31 +01:00
Bartlomiej Zolnierkiewicz
6ea52226ca ide: use queue lock instead of ide_lock when possible
This is just a preparation for future changes and there should be no
functional changes caused by this patch since ide_lock is currently
also used as queue lock.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:31 +01:00
Bartlomiej Zolnierkiewicz
3c8a2cce47 ide: ide_lock + __blk_end_request() -> blk_end_request()
Use blk_end_request() instead of ide_lock + __blk_end_request()
in cdrom_end_request(), cdrom_newpc_intr(), __ide_end_request(),
ide_complete_pm_request() and ide_end_drive_cmd().

[ ide_lock is currently also used as queue lock ]

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:31 +01:00
Bartlomiej Zolnierkiewicz
a72b2147ec ide: push ide_lock to __ide_end_request()
__ide_end_request() needs ide_lock only for __blk_end_request()
call so push ide_lock taking inside __ide_end_requests().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:30 +01:00
Bartlomiej Zolnierkiewicz
1d0bf587df ide: ide_hwgroup_t.rq doesn't need an ide_lock held
While at it:
- no need to check for hwgroup presence in ide_dump_opcode()

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:30 +01:00
Bartlomiej Zolnierkiewicz
3e0e29f737 ide: unify ide_intr()'s exit points
Just a preparation for future changes.

There should be no functional changes caused by this patch.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-29 20:27:29 +01:00
Bartlomiej Zolnierkiewicz
1a659880ee Revert "ide: respect current DMA setting during resume"
This reverts commit e9eb838830 since
it could break resume (thanks to Paul Collins for the report).

I'll look into sorting this out properly for 2.6.29
but for 2.6.28 it is the best to just revert my patch.

Reported-by: Paul Collins <paul@burly.ondioline.org>
Cc: rjw@sisk.pl
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-08 17:42:35 +01:00
Bartlomiej Zolnierkiewicz
6b7d8fc362 ide: fix build for DEBUG_PM
Also while at it:

* Drop unused arguments from ide_complete_power_step().

* Move DEBUG_PM printk() from ide_end_drive_cmd() to
  ide_complete_power_step().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-02 20:40:03 +01:00
Bartlomiej Zolnierkiewicz
e9eb838830 ide: respect current DMA setting during resume
Respect current DMA setting during resume, otherwise PIO timings
may get destroyed if host uses shared PIO/MWDMA timings.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-02 20:40:03 +01:00
Michael Schmitz
f9e3326dce ide: fix the ide_release_lock imbalance
ide_release_lock() spits out lots of:

	ide_release_lock: bug

warnings on Atari Falcon.

Fix the ide_release_lock imbalance.

Signed-off-by: Michael Schmitz <schmitz@biophys.uni-duesseldorf.de>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-12-02 20:40:02 +01:00
Jens Axboe
f73e2d13a1 block: remove __generic_unplug_device() from exports
The only out-of-core user is IDE, and that should be using
blk_start_queueing() instead.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-17 14:03:08 +02:00
Elias Oltmanns
4abdc6ee7c ide: Implement disk shock protection support (v4)
On user request (through sysfs), the IDLE IMMEDIATE command with UNLOAD
FEATURE as specified in ATA-7 is issued to the device and processing of
the request queue is stopped thereafter until the specified timeout
expires or user space asks to resume normal operation. This is supposed
to prevent the heads of a hard drive from accidentally crashing onto the
platter when a heavy shock is anticipated (like a falling laptop expected
to hit the floor). Port resets are deferred whenever a device on that
port is in the parked state.

v3:
Elias Oltmanns <eo@nebensachen.de> wrote:
[...]
> >> 1. Make sure that no negative value is being passed to
> >>    jiffies_to_msecs() in ide_park_show().
> >> 2. Drop the superfluous variable hwif in ide_special_rq().
> >> 3. Skip initialisation of task and tf in ide_special_rq() if we are not
> >>    handling a (un)park request.
> >
> > Well, #3 should have been done differently because we donn't want to
> > check for REQ_(UN)?PARK_HEADS more often than is necessary.
> 
> While preparing the backport to 2.6.27, it has just occurred to me that
> we need to clear the IDE_DFLAG_PARKED flag in ide_disk_pre_reset()
> because this flag must not be set after *any* sort of access to the
> device.

v4:
Fix a memory leak due to a missing blk_put_request() in
issue_park_cmd(). Additionally, we should plug the queue when enqueueing
the unpark request because there is no guarantee that the park timeout
has not expired by then. Even though the chance for that to happen is
very slim, the request might end up hanging in the queue until the next
I/O operation is queued up. While at it, clean up the code a little:
- make issue_park_cmd() a function of type void since nobody cares for
  the return value anyway;
- use blk_start_queueing() instead of __blk_run_queue() since we don't
  have to worry about recursion;
- remove a superfluous pointer deference in task_no_data_intr().

Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
Cc: Jeff Garzik <jeff@garzik.org>,
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Cc: Tejun Heo <htejun@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
2008-10-13 21:39:50 +02:00