Put some information (and pointers to more) into the kernel's doc tree,
describing briefly the interface to the kernel's disk head unloading
facility. Information about how to set up a complete shock protection
system under GNU/Linux can be found on the web and is referenced
accordingly.
v3:
Here is some final polish including various spelling corrections
pointed out by Grant Grundler and Peter Moulder. Also, I have added some
information about the timing constraints related to disk head parking.
The patch looks more impressive than it really is and I think it would
be alright just to incorporate it into the original patch so as not to
clutter up the git log.
Signed-off-by: Elias Oltmanns <[email protected]>
Cc: Jeff Garzik <[email protected]>
Cc: Randy Dunlap <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
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 <[email protected]> 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 <[email protected]>
Cc: Jeff Garzik <[email protected]>,
Cc: Randy Dunlap <[email protected]>
Cc: Tejun Heo <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
In function ide_devset_execute() we should use __GFP_WAIT rather than
GFP_KERNEL. Also, the allocation cannot possibly fail at that point.
More importantly, there is a potential memory leak in the device probing
code. The infrastructure seems rather complex and I hope I haven't messed
anything up by trying to fix this.
Signed-off-by: Elias Oltmanns <[email protected]>
[bart: remove superfluous ide_lock taking]
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Use a special request for serialisation purposes and get rid of the
awkward ide_spin_wait_hwgroup(). This also involves converting the
ide_devset structure so it can be shared by the /proc and the ioctl code.
Signed-off-by: Elias Oltmanns <[email protected]>
[bart: use rq->cmd[] directly]
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
blk_start_queueing() should act like the generic queue unplugging
and kicking and ignore a stopped queue. Such a queue may not be
run until after a call to blk_start_queue().
Signed-off-by: Elias Oltmanns <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
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). In fact, the whole port stops processing
commands until the timeout has expired in order to avoid any resets due
to failed commands on another device.
Signed-off-by: Elias Oltmanns <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>
Add a function to check an ATA device's id for head unload support as
specified in ATA-7.
Signed-off-by: Elias Oltmanns <[email protected]>
Signed-off-by: Jeff Garzik <[email protected]>
Make sure that each error condition during the execution of an
HDIO_DRIVE_RESET ioctl is actually reported to the calling process.
Also, unify the exit path of reset_pollfunc() when returning ide_stopped
since the need of ->port_ops->reset_poll() to be treated specially has
vanished (way back, it seems).
Signed-off-by: Elias Oltmanns <[email protected]>
Cc: "Alan Cox" <[email protected]>
Cc: "Randy Dunlap" <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Alter the entry for HDIO_DRIVE_RESET in Documentation/ioctl/hdio.txt to
reflect a functional change in the driver. Besides, the entry has been
inaccurate before.
Signed-off-by: Elias Oltmanns <[email protected]>
Cc: "Alan Cox" <[email protected]>
Cc: "Randy Dunlap" <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Remove some code which has been made obsolete and hasn't worked properly
before anyway. Part of the infrastructure may be reintroduced in a
follow up patch to implement a working command aborting facility.
Signed-off-by: Elias Oltmanns <[email protected]>
Cc: "Alan Cox" <[email protected]>
Cc: "Randy Dunlap" <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Currently, the code path executing an HDIO_DRIVE_RESET ioctl is broken
in various ways. Most importantly, it is treated as an out of band
request in an illegal way which may very likely lead to system lock ups.
Use the drive's request queue to avoid this problem (and fix a locking
issue for free along the way).
Signed-off-by: Elias Oltmanns <[email protected]>
Cc: "Alan Cox" <[email protected]>
Cc: "Randy Dunlap" <[email protected]>
Signed-off-by: Bartlomiej Zolnierkiewicz <[email protected]>
Make cpufreq_conservative handle out-of-sync events properly
Currently, the cpufreq_conservative governor doesn't get notified when the
actual frequency the cpu is running at differs from what cpufreq thought it
was. As a result the cpu may stay at the maximum frequency after a s2ram /
resume cycle even though the system is idle.
Signed-off-by: Elias Oltmanns <[email protected]>
Signed-off-by: Dave Jones <[email protected]>
Elias Oltmanns