On Tue, 2006-04-11 at 22:48 +0900, Tejun Heo wrote:
> +
> +/**
> + * ata_eh_revive - revive host port after error
> + * @ap: host port to revive
> + * @action: action to perform to revive @ap
> + * @softreset: softreset method (can be NULL)
> + * @hardreset: hardreset method (can be NULL)
> + * @postreset: postreset method (can be NULL)
> + *
> + * Perform action specified by @action to revive host port @ap
> + * after error.
> + *
> + * LOCKING:
> + * Kernel thread context (may sleep).
> + */
> +int ata_eh_revive(struct ata_port *ap, unsigned int action,
> + ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
> + ata_postreset_fn_t postreset)
> +{
> + int scr_valid = ap->cbl == ATA_CBL_SATA && ap->ops->scr_read;
> + unsigned int classes[ATA_MAX_DEVICES];
> + int tries[ATA_MAX_DEVICES], reset_tries, nr_enabled;
> + struct ata_device *dev;
> + ata_reset_fn_t reset;
> + int i, down_xfermask, rc = 0;
> +
> + if (!action)
> + goto out;
> +
> + reset_tries = ATA_EH_MAX_TRIES;
> + nr_enabled = 0;
> + for (i = 0; i < ATA_MAX_DEVICES; i++) {
> + tries[i] = ATA_EH_MAX_TRIES;
> + if (ata_dev_enabled(&ap->device[i]))
> + nr_enabled++;
> + }
> +
> + /* revalidate */
> + if (action == ATA_PORT_REVALIDATE) {
> + for (i = 0; i < ATA_MAX_DEVICES; i++) {
> + struct ata_device *dev = &ap->device[i];
> + if (!ata_dev_enabled(dev) ||
> + !(dev->flags & ATA_DFLAG_FAILED))
> + continue;
> + if (ata_dev_revalidate(ap, dev, 0))
> + break;
> + }
> + if (i == ATA_MAX_DEVICES) {
> + rc = 0;
> + goto out;
> + }
> +
> + action |= ATA_PORT_SOFTRESET;
> + }
> + action &= ~ATA_PORT_REVALIDATE;
> +
> + /* Skip reset if possible. */
> + if (!nr_enabled && !(ap->flags & ATA_FLAG_FROZEN))
> + goto out;
> +
> + /* give devices some time to breath */
> + ata_eh_wait_before_reset(ap);
> +
> + if (softreset && (!hardreset || (!ata_set_sata_spd_needed(ap) &&
> + action == ATA_PORT_SOFTRESET)))
> + reset = softreset;
> + else
> + reset = hardreset;
> +
> + retry:
> + down_xfermask = 0;
> +
> + /* reset. postreset is responsible for thawing the port. */
> + printk("ata%u: %s resetting channel for error handling\n",
> + ap->id, reset == softreset ? "soft" : "hard");
> +
> + rc = ata_do_reset(ap, reset, postreset, classes);
> + if (rc)
> + goto fail_reset;
> +
> + /* revalidate and reconfigure devices */
> + for (i = 0; i < ATA_MAX_DEVICES; i++) {
> + dev = &ap->device[i];
> +
> + if (!ata_dev_enabled(dev))
> + continue;
> +
> + if (scr_valid && !sata_dev_present(ap)) {
> + rc = -EIO;
> + goto fail;
> + }
> +
> + rc = ata_dev_revalidate(ap, dev, 1);
> + if (rc)
> + goto fail;
> + }
> +
> + /* configure transfer mode */
> + if (ap->ops->set_mode) {
> + /* FIXME: make ->set_mode handle no device case and
> + * return error code and failing device on failure as
> + * ata_set_mode() does.
> + */
> + for (i = 0; i < ATA_MAX_DEVICES; i++)
> + if (ata_dev_enabled(&ap->device[i])) {
> + ap->ops->set_mode(ap);
> + break;
> + }
> + rc = 0;
> + } else
> + rc = ata_set_mode(ap, &dev);
> +
> + if (rc) {
> + down_xfermask = 1;
> + goto fail;
> + }
> +
> + goto out;
> +
> + fail_reset:
> + if (!--reset_tries) {
> + printk(KERN_ERR "ata%u: EH reset failed, giving up\n", ap->id);
> + goto out;
> + }
> + if (reset == hardreset)
> + ata_down_sata_spd_limit(ap);
> + if (hardreset)
> + reset = hardreset;
> +
> + printk(KERN_WARNING "ata%u: EH reset failed, will retry in 5 secs\n",
> + ap->id);
> + ssleep(5);
> + goto retry;
> +
> + fail:
> + switch (rc) {
> + case -EINVAL:
> + case -ENODEV:
> + tries[dev->devno] = 0;
> + break;
> + case -EIO:
> + ata_down_sata_spd_limit(ap);
> + default:
> + tries[dev->devno]--;
> + if (down_xfermask &&
> + ata_down_xfermask_limit(ap, dev, tries[dev->devno] == 1))
> + tries[dev->devno] = 0;
> + }
> +
> + if (!tries[dev->devno]) {
> + ata_dev_disable(ap, dev);
> + nr_enabled--;
> + }
> +
> + if (nr_enabled) {
> + printk(KERN_WARNING "ata%u: some devices seem to be offline, "
> + "will retry in 5 secs\n", ap->id);
> + ssleep(5);
> + } else {
> + /* no device left, repeat fast */
> + msleep(500);
> + }
> +
> + if (hardreset)
> + reset = hardreset;
> + goto retry;
> +
> + out:
> + for (i = 0; i < ATA_MAX_DEVICES; i++) {
> + dev = &ap->device[i];
> + dev->flags &= ~ATA_DFLAG_FAILED;
> + if (rc)
> + ata_dev_disable(ap, dev);
> + }
> +
> + return rc;
> +}
Tejun,
I did some initial hotplug test in our lab today. And
this is the printk output in dmesg when I unplug the
SATA disk at port 2:
ata2: stat 0x50 err 0x0 SError 0x90402 action 0x2
(irq_stat 0x04400000, PHY RDY changed)
ata2: soft resetting channel for error handling
ata2: SATA link down (SStatus 21 SControl 300)
ata2: limiting SATA link speed to 1.5 Gbps
ata2: some devices seem to be offline, will retry in 5 secs
ata2: hard resetting channel for error handling
ata2: SATA link down (SStatus 0 SControl 310)
ata2: some devices seem to be offline, will retry in 5 secs
ata2: hard resetting channel for error handling
ata2: SATA link down (SStatus 0 SControl 310)
ata2: dev 0 disabled
// why hard reset again??
ata2: hard resetting channel for error handling
ata2: SATA link down (SStatus 0 SControl 310)
// ??
ata2: dev 0 detaching (SCSI 1:0:0:0)
My question is: why hard-reset is executed again after
dev0 at ata2 has been disabled?
Could you help me understand the idea behind this logic?
Thanks,
Forrest
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