5 files changed, 246 insertions, 3 deletions

diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 6acea41eb7ca..aeadd00411a1 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -316,6 +316,7 @@ static struct device_attribute *ahci_shost_attrs[] = {
 
 static struct device_attribute *ahci_sdev_attrs[] = {
         &dev_attr_sw_activity,
+        &dev_attr_unload_heads,
         NULL
 };
 
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 6eed58e35e12..1ee9499bd343 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5378,6 +5378,7 @@ struct ata_port *ata_port_alloc(struct ata_host *host)
         INIT_WORK(&ap->scsi_rescan_task, ata_scsi_dev_rescan);
         INIT_LIST_HEAD(&ap->eh_done_q);
         init_waitqueue_head(&ap->eh_wait_q);
+        init_completion(&ap->park_req_pending);
         init_timer_deferrable(&ap->fastdrain_timer);
         ap->fastdrain_timer.function = ata_eh_fastdrain_timerfn;
         ap->fastdrain_timer.data = (unsigned long)ap;
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 99037a4860d9..33ac5ea4f531 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -2536,6 +2536,80 @@ int ata_eh_reset(struct ata_link *link, int classify,
         goto retry;
 }
 
+static inline void ata_eh_pull_park_action(struct ata_port *ap)
+{
+        struct ata_link *link;
+        struct ata_device *dev;
+        unsigned long flags;
+
+        /*
+         * This function can be thought of as an extended version of
+         * ata_eh_about_to_do() specially crafted to accommodate the
+         * requirements of ATA_EH_PARK handling. Since the EH thread
+         * does not leave the do {} while () loop in ata_eh_recover as
+         * long as the timeout for a park request to *one* device on
+         * the port has not expired, and since we still want to pick
+         * up park requests to other devices on the same port or
+         * timeout updates for the same device, we have to pull
+         * ATA_EH_PARK actions from eh_info into eh_context.i
+         * ourselves at the beginning of each pass over the loop.
+         *
+         * Additionally, all write accesses to &ap->park_req_pending
+         * through INIT_COMPLETION() (see below) or complete_all()
+         * (see ata_scsi_park_store()) are protected by the host lock.
+         * As a result we have that park_req_pending.done is zero on
+         * exit from this function, i.e. when ATA_EH_PARK actions for
+         * *all* devices on port ap have been pulled into the
+         * respective eh_context structs. If, and only if,
+         * park_req_pending.done is non-zero by the time we reach
+         * wait_for_completion_timeout(), another ATA_EH_PARK action
+         * has been scheduled for at least one of the devices on port
+         * ap and we have to cycle over the do {} while () loop in
+         * ata_eh_recover() again.
+         */
+
+        spin_lock_irqsave(ap->lock, flags);
+        INIT_COMPLETION(ap->park_req_pending);
+        ata_port_for_each_link(link, ap) {
+                ata_link_for_each_dev(dev, link) {
+                        struct ata_eh_info *ehi = &link->eh_info;
+
+                        link->eh_context.i.dev_action[dev->devno] |=
+                                ehi->dev_action[dev->devno] & ATA_EH_PARK;
+                        ata_eh_clear_action(link, dev, ehi, ATA_EH_PARK);
+                }
+        }
+        spin_unlock_irqrestore(ap->lock, flags);
+}
+
+static void ata_eh_park_issue_cmd(struct ata_device *dev, int park)
+{
+        struct ata_eh_context *ehc = &dev->link->eh_context;
+        struct ata_taskfile tf;
+        unsigned int err_mask;
+
+        ata_tf_init(dev, &tf);
+        if (park) {
+                ehc->unloaded_mask |= 1 << dev->devno;
+                tf.command = ATA_CMD_IDLEIMMEDIATE;
+                tf.feature = 0x44;
+                tf.lbal = 0x4c;
+                tf.lbam = 0x4e;
+                tf.lbah = 0x55;
+        } else {
+                ehc->unloaded_mask &= ~(1 << dev->devno);
+                tf.command = ATA_CMD_CHK_POWER;
+        }
+
+        tf.flags |= ATA_TFLAG_DEVICE | ATA_TFLAG_ISADDR;
+        tf.protocol |= ATA_PROT_NODATA;
+        err_mask = ata_exec_internal(dev, &tf, NULL, DMA_NONE, NULL, 0, 0);
+        if (park && (err_mask || tf.lbal != 0xc4)) {
+                ata_dev_printk(dev, KERN_ERR, "head unload failed!\n");
+                ehc->unloaded_mask &= ~(1 << dev->devno);
+        }
+}
+
 static int ata_eh_revalidate_and_attach(struct ata_link *link,
                                         struct ata_device **r_failed_dev)
 {
@@ -2845,7 +2919,7 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         struct ata_device *dev;
         int nr_failed_devs;
         int rc;
-        unsigned long flags;
+        unsigned long flags, deadline;
 
         DPRINTK("ENTER\n");
 
@@ -2919,6 +2993,56 @@ int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                 }
         }
 
+        do {
+                unsigned long now;
+
+                /*
+                 * clears ATA_EH_PARK in eh_info and resets
+                 * ap->park_req_pending
+                 */
+                ata_eh_pull_park_action(ap);
+
+                deadline = jiffies;
+                ata_port_for_each_link(link, ap) {
+                        ata_link_for_each_dev(dev, link) {
+                                struct ata_eh_context *ehc = &link->eh_context;
+                                unsigned long tmp;
+
+                                if (dev->class != ATA_DEV_ATA)
+                                        continue;
+                                if (!(ehc->i.dev_action[dev->devno] &
+                                      ATA_EH_PARK))
+                                        continue;
+                                tmp = dev->unpark_deadline;
+                                if (time_before(deadline, tmp))
+                                        deadline = tmp;
+                                else if (time_before_eq(tmp, jiffies))
+                                        continue;
+                                if (ehc->unloaded_mask & (1 << dev->devno))
+                                        continue;
+
+                                ata_eh_park_issue_cmd(dev, 1);
+                        }
+                }
+
+                now = jiffies;
+                if (time_before_eq(deadline, now))
+                        break;
+
+                deadline = wait_for_completion_timeout(&ap->park_req_pending,
+                                                       deadline - now);
+        } while (deadline);
+        ata_port_for_each_link(link, ap) {
+                ata_link_for_each_dev(dev, link) {
+                        if (!(link->eh_context.unloaded_mask &
+                              (1 << dev->devno)))
+                                continue;
+
+                        ata_eh_park_issue_cmd(dev, 0);
+                        ata_eh_done(link, dev, ATA_EH_PARK);
+                }
+        }
+
         /* the rest */
         ata_port_for_each_link(link, ap) {
                 struct ata_eh_context *ehc = &link->eh_context;
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b9d3ba423cb2..fccd5e496c62 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -183,6 +183,105 @@ DEVICE_ATTR(link_power_management_policy, S_IRUGO | S_IWUSR,
                 ata_scsi_lpm_show, ata_scsi_lpm_put);
 EXPORT_SYMBOL_GPL(dev_attr_link_power_management_policy);
 
+static ssize_t ata_scsi_park_show(struct device *device,
+                                  struct device_attribute *attr, char *buf)
+{
+        struct scsi_device *sdev = to_scsi_device(device);
+        struct ata_port *ap;
+        struct ata_link *link;
+        struct ata_device *dev;
+        unsigned long flags;
+        unsigned int uninitialized_var(msecs);
+        int rc = 0;
+
+        ap = ata_shost_to_port(sdev->host);
+
+        spin_lock_irqsave(ap->lock, flags);
+        dev = ata_scsi_find_dev(ap, sdev);
+        if (!dev) {
+                rc = -ENODEV;
+                goto unlock;
+        }
+        if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
+                rc = -EOPNOTSUPP;
+                goto unlock;
+        }
+
+        link = dev->link;
+        if (ap->pflags & ATA_PFLAG_EH_IN_PROGRESS &&
+            link->eh_context.unloaded_mask & (1 << dev->devno) &&
+            time_after(dev->unpark_deadline, jiffies))
+                msecs = jiffies_to_msecs(dev->unpark_deadline - jiffies);
+        else
+                msecs = 0;
+
+unlock:
+        spin_unlock_irq(ap->lock);
+
+        return rc ? rc : snprintf(buf, 20, "%u\n", msecs);
+}
+
+static ssize_t ata_scsi_park_store(struct device *device,
+                                   struct device_attribute *attr,
+                                   const char *buf, size_t len)
+{
+        struct scsi_device *sdev = to_scsi_device(device);
+        struct ata_port *ap;
+        struct ata_device *dev;
+        long int input;
+        unsigned long flags;
+        int rc;
+
+        rc = strict_strtol(buf, 10, &input);
+        if (rc || input < -2)
+                return -EINVAL;
+        if (input > ATA_TMOUT_MAX_PARK) {
+                rc = -EOVERFLOW;
+                input = ATA_TMOUT_MAX_PARK;
+        }
+
+        ap = ata_shost_to_port(sdev->host);
+
+        spin_lock_irqsave(ap->lock, flags);
+        dev = ata_scsi_find_dev(ap, sdev);
+        if (unlikely(!dev)) {
+                rc = -ENODEV;
+                goto unlock;
+        }
+        if (dev->class != ATA_DEV_ATA) {
+                rc = -EOPNOTSUPP;
+                goto unlock;
+        }
+
+        if (input >= 0) {
+                if (dev->flags & ATA_DFLAG_NO_UNLOAD) {
+                        rc = -EOPNOTSUPP;
+                        goto unlock;
+                }
+
+                dev->unpark_deadline = ata_deadline(jiffies, input);
+                dev->link->eh_info.dev_action[dev->devno] |= ATA_EH_PARK;
+                ata_port_schedule_eh(ap);
+                complete(&ap->park_req_pending);
+        } else {
+                switch (input) {
+                case -1:
+                        dev->flags &= ~ATA_DFLAG_NO_UNLOAD;
+                        break;
+                case -2:
+                        dev->flags |= ATA_DFLAG_NO_UNLOAD;
+                        break;
+                }
+        }
+unlock:
+        spin_unlock_irqrestore(ap->lock, flags);
+
+        return rc ? rc : len;
+}
+DEVICE_ATTR(unload_heads, S_IRUGO | S_IWUSR,
+            ata_scsi_park_show, ata_scsi_park_store);
+EXPORT_SYMBOL_GPL(dev_attr_unload_heads);
+
 static void ata_scsi_set_sense(struct scsi_cmnd *cmd, u8 sk, u8 asc, u8 ascq)
 {
         cmd->result = (DRIVER_SENSE << 24) | SAM_STAT_CHECK_CONDITION;
@@ -269,6 +368,12 @@ DEVICE_ATTR(sw_activity, S_IWUGO | S_IRUGO, ata_scsi_activity_show,
                         ata_scsi_activity_store);
 EXPORT_SYMBOL_GPL(dev_attr_sw_activity);
 
+struct device_attribute *ata_common_sdev_attrs[] = {
+        &dev_attr_unload_heads,
+        NULL
+};
+EXPORT_SYMBOL_GPL(ata_common_sdev_attrs);
+
 static void ata_scsi_invalid_field(struct scsi_cmnd *cmd,
                                    void (*done)(struct scsi_cmnd *))
 {
@@ -954,6 +1059,9 @@ static int atapi_drain_needed(struct request *rq)
 static int ata_scsi_dev_config(struct scsi_device *sdev,
                                struct ata_device *dev)
 {
+        if (!ata_id_has_unload(dev->id))
+                dev->flags |= ATA_DFLAG_NO_UNLOAD;
+
         /* configure max sectors */
         blk_queue_max_sectors(sdev->request_queue, dev->max_sectors);
 
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 244ff601559a..1f44cfb847e1 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -146,6 +146,7 @@ enum {
         ATA_DFLAG_SPUNDOWN      = (1 << 14), /* XXX: for spindown_compat */
         ATA_DFLAG_SLEEPING      = (1 << 15), /* device is sleeping */
         ATA_DFLAG_DUBIOUS_XFER  = (1 << 16), /* data transfer not verified */
+        ATA_DFLAG_NO_UNLOAD     = (1 << 17), /* device doesn't support unload */
         ATA_DFLAG_INIT_MASK     = (1 << 24) - 1,
 
         ATA_DFLAG_DETACH        = (1 << 24),
@@ -244,6 +245,7 @@ enum {
         ATA_TMOUT_BOOT          = 30000,        /* heuristic */
         ATA_TMOUT_BOOT_QUICK    =  7000,        /* heuristic */
         ATA_TMOUT_INTERNAL_QUICK = 5000,
+        ATA_TMOUT_MAX_PARK      = 30000,
 
         /* FIXME: GoVault needs 2s but we can't afford that without
          * parallel probing.  800ms is enough for iVDR disk
@@ -319,8 +321,9 @@ enum {
         ATA_EH_RESET            = ATA_EH_SOFTRESET | ATA_EH_HARDRESET,
         ATA_EH_ENABLE_LINK      = (1 << 3),
         ATA_EH_LPM              = (1 << 4),  /* link power management action */
+        ATA_EH_PARK             = (1 << 5), /* unload heads and stop I/O */
 
-        ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE,
+        ATA_EH_PERDEV_MASK      = ATA_EH_REVALIDATE | ATA_EH_PARK,
         ATA_EH_ALL_ACTIONS      = ATA_EH_REVALIDATE | ATA_EH_RESET |
                                   ATA_EH_ENABLE_LINK | ATA_EH_LPM,
 
@@ -454,6 +457,7 @@ enum link_pm {
         MEDIUM_POWER,
 };
 extern struct device_attribute dev_attr_link_power_management_policy;
+extern struct device_attribute dev_attr_unload_heads;
 extern struct device_attribute dev_attr_em_message_type;
 extern struct device_attribute dev_attr_em_message;
 extern struct device_attribute dev_attr_sw_activity;
@@ -566,6 +570,7 @@ struct ata_device {
         /* n_sector is used as CLEAR_OFFSET, read comment above CLEAR_OFFSET */
         u64                     n_sectors;      /* size of device, if ATA */
         unsigned int            class;          /* ATA_DEV_xxx */
+        unsigned long           unpark_deadline;
 
         u8                      pio_mode;
         u8                      dma_mode;
@@ -623,6 +628,7 @@ struct ata_eh_context {
                                                [ATA_EH_CMD_TIMEOUT_TABLE_SIZE];
         unsigned int            classes[ATA_MAX_DEVICES];
         unsigned int            did_probe_mask;
+        unsigned int            unloaded_mask;
         unsigned int            saved_ncq_enabled;
         u8                      saved_xfer_mode[ATA_MAX_DEVICES];
         /* timestamp for the last reset attempt or success */
@@ -712,6 +718,7 @@ struct ata_port {
         struct list_head        eh_done_q;
         wait_queue_head_t       eh_wait_q;
         int                     eh_tries;
+        struct completion       park_req_pending;
 
         pm_message_t            pm_mesg;
         int                     *pm_result;
@@ -1102,6 +1109,7 @@ extern void ata_std_error_handler(struct ata_port *ap);
  */
 extern const struct ata_port_operations ata_base_port_ops;
 extern const struct ata_port_operations sata_port_ops;
+extern struct device_attribute *ata_common_sdev_attrs[];
 
 #define ATA_BASE_SHT(drv_name)                                  \
         .module                 = THIS_MODULE,                  \
@@ -1116,7 +1124,8 @@ extern const struct ata_port_operations sata_port_ops;
         .proc_name              = drv_name,                     \
         .slave_configure        = ata_scsi_slave_config,        \
         .slave_destroy          = ata_scsi_slave_destroy,       \
-        .bios_param             = ata_std_bios_param
+        .bios_param             = ata_std_bios_param,           \
+        .sdev_attrs             = ata_common_sdev_attrs
 
 #define ATA_NCQ_SHT(drv_name)                                   \
         ATA_BASE_SHT(drv_name),                                 \