libata: reimplement suspend/resume support using sdev->manage_start_stop

Reimplement suspend/resume support using sdev->manage_start_stop.

* Device suspend/resume is now SCSI layer's responsibility and the
  code is simplified a lot.

* DPM is dropped.  This also simplifies code a lot.  Suspend/resume
  status is port-wide now.

* ata_scsi_device_suspend/resume() and ata_dev_ready() removed.

* Resume now has to wait for disk to spin up before proceeding.  I
  couldn't find easy way out as libata is in EH waiting for the
  disk to be ready and sd is waiting for EH to complete to issue
  START_STOP.

* sdev->manage_start_stop is set to 1 in ata_scsi_slave_config().
  This fixes spindown on shutdown and suspend-to-disk.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 4 insertions, 233 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 8256655ce7d9..412d6049afa3 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -77,29 +77,12 @@ static void ata_eh_finish(struct ata_port *ap);
 #ifdef CONFIG_PM
 static void ata_eh_handle_port_suspend(struct ata_port *ap);
 static void ata_eh_handle_port_resume(struct ata_port *ap);
-static int ata_eh_suspend(struct ata_port *ap,
-                          struct ata_device **r_failed_dev);
-static void ata_eh_prep_resume(struct ata_port *ap);
-static int ata_eh_resume(struct ata_port *ap, struct ata_device **r_failed_dev);
 #else /* CONFIG_PM */
 static void ata_eh_handle_port_suspend(struct ata_port *ap)
 { }
 
 static void ata_eh_handle_port_resume(struct ata_port *ap)
 { }
-
-static int ata_eh_suspend(struct ata_port *ap, struct ata_device **r_failed_dev)
-{
-        return 0;
-}
-
-static void ata_eh_prep_resume(struct ata_port *ap)
-{ }
-
-static int ata_eh_resume(struct ata_port *ap, struct ata_device **r_failed_dev)
-{
-        return 0;
-}
 #endif /* CONFIG_PM */
 
 static void ata_ering_record(struct ata_ering *ering, int is_io,
@@ -1791,7 +1774,7 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
                 if (ehc->i.flags & ATA_EHI_DID_RESET)
                         readid_flags |= ATA_READID_POSTRESET;
 
-                if (action & ATA_EH_REVALIDATE && ata_dev_ready(dev)) {
+                if ((action & ATA_EH_REVALIDATE) && ata_dev_enabled(dev)) {
                         if (ata_port_offline(ap)) {
                                 rc = -EIO;
                                 goto err;
@@ -1872,166 +1855,6 @@ static int ata_eh_revalidate_and_attach(struct ata_port *ap,
         return rc;
 }
 
-#ifdef CONFIG_PM
-/**
- *      ata_eh_suspend - handle suspend EH action
- *      @ap: target host port
- *      @r_failed_dev: result parameter to indicate failing device
- *
- *      Handle suspend EH action.  Disk devices are spinned down and
- *      other types of devices are just marked suspended.  Once
- *      suspended, no EH action to the device is allowed until it is
- *      resumed.
- *
- *      LOCKING:
- *      Kernel thread context (may sleep).
- *
- *      RETURNS:
- *      0 on success, -errno otherwise
- */
-static int ata_eh_suspend(struct ata_port *ap, struct ata_device **r_failed_dev)
-{
-        struct ata_device *dev;
-        int i, rc = 0;
-
-        DPRINTK("ENTER\n");
-
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                unsigned long flags;
-                unsigned int action, err_mask;
-
-                dev = &ap->device[i];
-                action = ata_eh_dev_action(dev);
-
-                if (!ata_dev_enabled(dev) || !(action & ATA_EH_SUSPEND))
-                        continue;
-
-                WARN_ON(dev->flags & ATA_DFLAG_SUSPENDED);
-
-                ata_eh_about_to_do(ap, dev, ATA_EH_SUSPEND);
-
-                if (dev->class == ATA_DEV_ATA && !(action & ATA_EH_PM_FREEZE)) {
-                        /* flush cache */
-                        rc = ata_flush_cache(dev);
-                        if (rc)
-                                break;
-
-                        /* spin down */
-                        err_mask = ata_do_simple_cmd(dev, ATA_CMD_STANDBYNOW1);
-                        if (err_mask) {
-                                ata_dev_printk(dev, KERN_ERR, "failed to "
-                                               "spin down (err_mask=0x%x)\n",
-                                               err_mask);
-                                rc = -EIO;
-                                break;
-                        }
-                }
-
-                spin_lock_irqsave(ap->lock, flags);
-                dev->flags |= ATA_DFLAG_SUSPENDED;
-                spin_unlock_irqrestore(ap->lock, flags);
-
-                ata_eh_done(ap, dev, ATA_EH_SUSPEND);
-        }
-
-        if (rc)
-                *r_failed_dev = dev;
-
-        DPRINTK("EXIT\n");
-        return rc;
-}
-
-/**
- *      ata_eh_prep_resume - prep for resume EH action
- *      @ap: target host port
- *
- *      Clear SUSPENDED in preparation for scheduled resume actions.
- *      This allows other parts of EH to access the devices being
- *      resumed.
- *
- *      LOCKING:
- *      Kernel thread context (may sleep).
- */
-static void ata_eh_prep_resume(struct ata_port *ap)
-{
-        struct ata_device *dev;
-        unsigned long flags;
-        int i;
-
-        DPRINTK("ENTER\n");
-
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                unsigned int action;
-
-                dev = &ap->device[i];
-                action = ata_eh_dev_action(dev);
-
-                if (!ata_dev_enabled(dev) || !(action & ATA_EH_RESUME))
-                        continue;
-
-                spin_lock_irqsave(ap->lock, flags);
-                dev->flags &= ~ATA_DFLAG_SUSPENDED;
-                spin_unlock_irqrestore(ap->lock, flags);
-        }
-
-        DPRINTK("EXIT\n");
-}
-
-/**
- *      ata_eh_resume - handle resume EH action
- *      @ap: target host port
- *      @r_failed_dev: result parameter to indicate failing device
- *
- *      Handle resume EH action.  Target devices are already reset and
- *      revalidated.  Spinning up is the only operation left.
- *
- *      LOCKING:
- *      Kernel thread context (may sleep).
- *
- *      RETURNS:
- *      0 on success, -errno otherwise
- */
-static int ata_eh_resume(struct ata_port *ap, struct ata_device **r_failed_dev)
-{
-        struct ata_device *dev;
-        int i, rc = 0;
-
-        DPRINTK("ENTER\n");
-
-        for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                unsigned int action, err_mask;
-
-                dev = &ap->device[i];
-                action = ata_eh_dev_action(dev);
-
-                if (!ata_dev_enabled(dev) || !(action & ATA_EH_RESUME))
-                        continue;
-
-                ata_eh_about_to_do(ap, dev, ATA_EH_RESUME);
-
-                if (dev->class == ATA_DEV_ATA && !(action & ATA_EH_PM_FREEZE)) {
-                        err_mask = ata_do_simple_cmd(dev,
-                                                     ATA_CMD_IDLEIMMEDIATE);
-                        if (err_mask) {
-                                ata_dev_printk(dev, KERN_ERR, "failed to "
-                                               "spin up (err_mask=0x%x)\n",
-                                               err_mask);
-                                rc = -EIO;
-                                break;
-                        }
-                }
-
-                ata_eh_done(ap, dev, ATA_EH_RESUME);
-        }
-
-        if (rc)
-                *r_failed_dev = dev;
-
-        DPRINTK("EXIT\n");
-        return 0;
-}
-#endif /* CONFIG_PM */
-
 static int ata_port_nr_enabled(struct ata_port *ap)
 {
         int i, cnt = 0;
@@ -2057,17 +1880,6 @@ static int ata_eh_skip_recovery(struct ata_port *ap)
         struct ata_eh_context *ehc = &ap->eh_context;
         int i;
 
-        /* skip if all possible devices are suspended */
-        for (i = 0; i < ata_port_max_devices(ap); i++) {
-                struct ata_device *dev = &ap->device[i];
-
-                if (!(dev->flags & ATA_DFLAG_SUSPENDED))
-                        break;
-        }
-
-        if (i == ata_port_max_devices(ap))
-                return 1;
-
         /* thaw frozen port, resume link and recover failed devices */
         if ((ap->pflags & ATA_PFLAG_FROZEN) ||
             (ehc->i.flags & ATA_EHI_RESUME_LINK) || ata_port_nr_enabled(ap))
@@ -2147,9 +1959,6 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         if (ap->pflags & ATA_PFLAG_UNLOADING)
                 goto out;
 
-        /* prep for resume */
-        ata_eh_prep_resume(ap);
-
         /* skip EH if possible. */
         if (ata_eh_skip_recovery(ap))
                 ehc->i.action = 0;
@@ -2177,11 +1986,6 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         if (rc)
                 goto dev_fail;
 
-        /* resume devices */
-        rc = ata_eh_resume(ap, &dev);
-        if (rc)
-                goto dev_fail;
-
         /* configure transfer mode if necessary */
         if (ehc->i.flags & ATA_EHI_SETMODE) {
                 rc = ata_set_mode(ap, &dev);
@@ -2190,11 +1994,6 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                 ehc->i.flags &= ~ATA_EHI_SETMODE;
         }
 
-        /* suspend devices */
-        rc = ata_eh_suspend(ap, &dev);
-        if (rc)
-                goto dev_fail;
-
         goto out;
 
  dev_fail:
@@ -2390,22 +2189,13 @@ static void ata_eh_handle_port_suspend(struct ata_port *ap)
  *
  *      Resume @ap.
  *
- *      This function also waits upto one second until all devices
- *      hanging off this port requests resume EH action.  This is to
- *      prevent invoking EH and thus reset multiple times on resume.
- *
- *      On DPM resume, where some of devices might not be resumed
- *      together, this may delay port resume upto one second, but such
- *      DPM resumes are rare and 1 sec delay isn't too bad.
- *
  *      LOCKING:
  *      Kernel thread context (may sleep).
  */
 static void ata_eh_handle_port_resume(struct ata_port *ap)
 {
-        unsigned long timeout;
         unsigned long flags;
-        int i, rc = 0;
+        int rc = 0;
 
         /* are we resuming? */
         spin_lock_irqsave(ap->lock, flags);
@@ -2416,31 +2206,12 @@ static void ata_eh_handle_port_resume(struct ata_port *ap)
         }
         spin_unlock_irqrestore(ap->lock, flags);
 
-        /* spurious? */
-        if (!(ap->pflags & ATA_PFLAG_SUSPENDED))
-                goto done;
+        WARN_ON(!(ap->pflags & ATA_PFLAG_SUSPENDED));
 
         if (ap->ops->port_resume)
                 rc = ap->ops->port_resume(ap);
 
-        /* give devices time to request EH */
-        timeout = jiffies + HZ; /* 1s max */
-        while (1) {
-                for (i = 0; i < ATA_MAX_DEVICES; i++) {
-                        struct ata_device *dev = &ap->device[i];
-                        unsigned int action = ata_eh_dev_action(dev);
-
-                        if ((dev->flags & ATA_DFLAG_SUSPENDED) &&
-                            !(action & ATA_EH_RESUME))
-                                break;
-                }
-
-                if (i == ATA_MAX_DEVICES || time_after(jiffies, timeout))
-                        break;
-                msleep(10);
-        }
-
- done:
+        /* report result */
         spin_lock_irqsave(ap->lock, flags);
         ap->pflags &= ~(ATA_PFLAG_PM_PENDING | ATA_PFLAG_SUSPENDED);
         if (ap->pm_result) {