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    SubjectRe: [PATCH 3/4 v2] ide: Implement disk shock protection support
    Date
    Elias Oltmanns <eo@nebensachen.de> wrote:
    > Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> wrote:
    >> On Wednesday 17 September 2008 09:38:37 Elias Oltmanns wrote:
    >
    >>> 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.
    >>>
    >>> Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
    >>
    >> applied
    >
    > Hi Bart,
    >
    > may I ask you to apply yet another inter-diff? This is in order to
    > address three issues:
    >
    > 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. Here is a
    revised version of the inter-diff.

    Regards,

    Elias


    Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
    ---
    diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
    index 09d10a5..77c6eae 100644
    --- a/drivers/ide/ide-io.c
    +++ b/drivers/ide/ide-io.c
    @@ -672,25 +672,32 @@ EXPORT_SYMBOL_GPL(ide_devset_execute);

    static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
    {
    - ide_hwif_t *hwif = drive->hwif;
    - ide_task_t task;
    - struct ide_taskfile *tf = &task.tf;
    + u8 cmd = rq->cmd[0];
    +
    + if (cmd == REQ_PARK_HEADS || cmd == REQ_UNPARK_HEADS) {
    + ide_task_t task;
    + struct ide_taskfile *tf = &task.tf;
    +
    + memset(&task, 0, sizeof(task));
    + if (cmd == REQ_PARK_HEADS) {
    + drive->sleep = *(unsigned long *)rq->special;
    + drive->dev_flags |= IDE_DFLAG_SLEEPING;
    + tf->command = ATA_CMD_IDLEIMMEDIATE;
    + tf->feature = 0x44;
    + tf->lbal = 0x4c;
    + tf->lbam = 0x4e;
    + tf->lbah = 0x55;
    + task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
    + } else /* cmd == REQ_UNPARK_HEADS */
    + tf->command = ATA_CMD_CHK_POWER;
    +
    + task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
    + task.rq = rq;
    + drive->hwif->data_phase = task.data_phase = TASKFILE_NO_DATA;
    + return do_rw_taskfile(drive, &task);
    + }

    - memset(&task, 0, sizeof(task));
    - switch (rq->cmd[0]) {
    - case REQ_PARK_HEADS:
    - drive->sleep = *(unsigned long *)rq->special;
    - drive->dev_flags |= IDE_DFLAG_SLEEPING;
    - tf->command = ATA_CMD_IDLEIMMEDIATE;
    - tf->feature = 0x44;
    - tf->lbal = 0x4c;
    - tf->lbam = 0x4e;
    - tf->lbah = 0x55;
    - task.tf_flags |= IDE_TFLAG_CUSTOM_HANDLER;
    - break;
    - case REQ_UNPARK_HEADS:
    - tf->command = ATA_CMD_CHK_POWER;
    - break;
    + switch (cmd) {
    case REQ_DEVSET_EXEC:
    {
    int err, (*setfunc)(ide_drive_t *, int) = rq->special;
    @@ -710,10 +717,6 @@ static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
    ide_end_request(drive, 0, 0);
    return ide_stopped;
    }
    - task.tf_flags |= IDE_TFLAG_TF | IDE_TFLAG_DEVICE;
    - task.rq = rq;
    - hwif->data_phase = task.data_phase = TASKFILE_NO_DATA;
    - return do_rw_taskfile(drive, &task);
    }

    static void ide_check_pm_state(ide_drive_t *drive, struct request *rq)
    diff --git a/drivers/ide/ide-park.c b/drivers/ide/ide-park.c
    index 35fc3ee..02d7e35 100644
    --- a/drivers/ide/ide-park.c
    +++ b/drivers/ide/ide-park.c
    @@ -61,15 +61,17 @@ ssize_t ide_park_show(struct device *dev, struct device_attribute *attr,
    char *buf)
    {
    ide_drive_t *drive = to_ide_device(dev);
    + unsigned long now;
    unsigned int msecs;

    if (drive->dev_flags & IDE_DFLAG_NO_UNLOAD)
    return -EOPNOTSUPP;

    spin_lock_irq(&ide_lock);
    + now = jiffies;
    if (drive->dev_flags & IDE_DFLAG_PARKED &&
    - time_after(drive->sleep, jiffies))
    - msecs = jiffies_to_msecs(drive->sleep - jiffies);
    + time_after(drive->sleep, now))
    + msecs = jiffies_to_msecs(drive->sleep - now);
    else
    msecs = 0;
    spin_unlock_irq(&ide_lock);

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