2 files changed, 115 insertions, 21 deletions

diff --git a/drivers/scsi/libata-eh.c b/drivers/scsi/libata-eh.c
index a049bffdf770..b53e2e7db498 100644
--- a/drivers/scsi/libata-eh.c
+++ b/drivers/scsi/libata-eh.c
@@ -932,10 +932,8 @@ static void ata_eh_analyze_serror(struct ata_port *ap)
                 err_mask |= AC_ERR_SYSTEM;
                 action |= ATA_EH_SOFTRESET;
         }
-        if (serror & (SERR_PHYRDY_CHG | SERR_DEV_XCHG)) {
-                err_mask |= AC_ERR_ATA_BUS;
-                action |= ATA_EH_HARDRESET;
-        }
+        if (serror & (SERR_PHYRDY_CHG | SERR_DEV_XCHG))
+                ata_ehi_hotplugged(&ehc->i);
 
         ehc->i.err_mask |= err_mask;
         ehc->i.action |= action;
@@ -1487,11 +1485,12 @@ static int ata_eh_reset(struct ata_port *ap, int classify,
         return rc;
 }
 
-static int ata_eh_revalidate(struct ata_port *ap,
-                             struct ata_device **r_failed_dev)
+static int ata_eh_revalidate_and_attach(struct ata_port *ap,
+                                        struct ata_device **r_failed_dev)
 {
         struct ata_eh_context *ehc = &ap->eh_context;
         struct ata_device *dev;
+        unsigned long flags;
         int i, rc = 0;
 
         DPRINTK("ENTER\n");
@@ -1513,6 +1512,23 @@ static int ata_eh_revalidate(struct ata_port *ap,
                                 break;
 
                         ehc->i.action &= ~ATA_EH_REVALIDATE;
+                } else if (dev->class == ATA_DEV_UNKNOWN &&
+                           ehc->tries[dev->devno] &&
+                           ata_class_enabled(ehc->classes[dev->devno])) {
+                        dev->class = ehc->classes[dev->devno];
+
+                        rc = ata_dev_read_id(dev, &dev->class, 1, dev->id);
+                        if (rc == 0)
+                                rc = ata_dev_configure(dev, 1);
+
+                        if (rc) {
+                                dev->class = ATA_DEV_UNKNOWN;
+                                break;
+                        }
+
+                        spin_lock_irqsave(&ap->host_set->lock, flags);
+                        ap->flags |= ATA_FLAG_SCSI_HOTPLUG;
+                        spin_unlock_irqrestore(&ap->host_set->lock, flags);
                 }
         }
 
@@ -1533,6 +1549,36 @@ static int ata_port_nr_enabled(struct ata_port *ap)
         return cnt;
 }
 
+static int ata_port_nr_vacant(struct ata_port *ap)
+{
+        int i, cnt = 0;
+
+        for (i = 0; i < ATA_MAX_DEVICES; i++)
+                if (ap->device[i].class == ATA_DEV_UNKNOWN)
+                        cnt++;
+        return cnt;
+}
+
+static int ata_eh_skip_recovery(struct ata_port *ap)
+{
+        struct ata_eh_context *ehc = &ap->eh_context;
+        int i;
+
+        if (ap->flags & ATA_FLAG_FROZEN || ata_port_nr_enabled(ap))
+                return 0;
+
+        /* skip if class codes for all vacant slots are ATA_DEV_NONE */
+        for (i = 0; i < ATA_MAX_DEVICES; i++) {
+                struct ata_device *dev = &ap->device[i];
+
+                if (dev->class == ATA_DEV_UNKNOWN &&
+                    ehc->classes[dev->devno] != ATA_DEV_NONE)
+                        return 0;
+        }
+
+        return 1;
+}
+
 /**
  *      ata_eh_recover - recover host port after error
  *      @ap: host port to recover
@@ -1543,9 +1589,10 @@ static int ata_port_nr_enabled(struct ata_port *ap)
  *
  *      This is the alpha and omega, eum and yang, heart and soul of
  *      libata exception handling.  On entry, actions required to
- *      recover each devices are recorded in eh_context.  This
- *      function executes all the operations with appropriate retrials
- *      and fallbacks to resurrect failed devices.
+ *      recover the port and hotplug requests are recorded in
+ *      eh_context.  This function executes all the operations with
+ *      appropriate retrials and fallbacks to resurrect failed
+ *      devices, detach goners and greet newcomers.
  *
  *      LOCKING:
  *      Kernel thread context (may sleep).
@@ -1568,6 +1615,19 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                 dev = &ap->device[i];
 
                 ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
+
+                /* process hotplug request */
+                if (dev->flags & ATA_DFLAG_DETACH)
+                        ata_eh_detach_dev(dev);
+
+                if (!ata_dev_enabled(dev) &&
+                    ((ehc->i.probe_mask & (1 << dev->devno)) &&
+                     !(ehc->did_probe_mask & (1 << dev->devno)))) {
+                        ata_eh_detach_dev(dev);
+                        ata_dev_init(dev);
+                        ehc->did_probe_mask |= (1 << dev->devno);
+                        ehc->i.action |= ATA_EH_SOFTRESET;
+                }
         }
 
  retry:
@@ -1575,15 +1635,18 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
         rc = 0;
 
         /* skip EH if possible. */
-        if (!ata_port_nr_enabled(ap) && !(ap->flags & ATA_FLAG_FROZEN))
+        if (ata_eh_skip_recovery(ap))
                 ehc->i.action = 0;
 
+        for (i = 0; i < ATA_MAX_DEVICES; i++)
+                ehc->classes[i] = ATA_DEV_UNKNOWN;
+
         /* reset */
         if (ehc->i.action & ATA_EH_RESET_MASK) {
                 ata_eh_freeze_port(ap);
 
-                rc = ata_eh_reset(ap, 0, prereset, softreset, hardreset,
-                                  postreset);
+                rc = ata_eh_reset(ap, ata_port_nr_vacant(ap), prereset,
+                                  softreset, hardreset, postreset);
                 if (rc) {
                         ata_port_printk(ap, KERN_ERR,
                                         "reset failed, giving up\n");
@@ -1593,8 +1656,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                 ata_eh_thaw_port(ap);
         }
 
-        /* revalidate existing devices */
-        rc = ata_eh_revalidate(ap, &dev);
+        /* revalidate existing devices and attach new ones */
+        rc = ata_eh_revalidate_and_attach(ap, &dev);
         if (rc)
                 goto dev_fail;
 
@@ -1612,6 +1675,8 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
  dev_fail:
         switch (rc) {
         case -ENODEV:
+                /* device missing, schedule probing */
+                ehc->i.probe_mask |= (1 << dev->devno);
         case -EINVAL:
                 ehc->tries[dev->devno] = 0;
                 break;
@@ -1624,15 +1689,31 @@ static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                         ehc->tries[dev->devno] = 0;
         }
 
-        /* disable device if it has used up all its chances */
-        if (ata_dev_enabled(dev) && !ehc->tries[dev->devno])
+        if (ata_dev_enabled(dev) && !ehc->tries[dev->devno]) {
+                /* disable device if it has used up all its chances */
                 ata_dev_disable(dev);
 
-        /* soft didn't work?  be haaaaard */
-        if (ehc->i.flags & ATA_EHI_DID_RESET)
-                ehc->i.action |= ATA_EH_HARDRESET;
-        else
-                ehc->i.action |= ATA_EH_SOFTRESET;
+                /* detach if offline */
+                if (ata_port_offline(ap))
+                        ata_eh_detach_dev(dev);
+
+                /* probe if requested */
+                if ((ehc->i.probe_mask & (1 << dev->devno)) &&
+                    !(ehc->did_probe_mask & (1 << dev->devno))) {
+                        ata_eh_detach_dev(dev);
+                        ata_dev_init(dev);
+
+                        ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
+                        ehc->did_probe_mask |= (1 << dev->devno);
+                        ehc->i.action |= ATA_EH_SOFTRESET;
+                }
+        } else {
+                /* soft didn't work?  be haaaaard */
+                if (ehc->i.flags & ATA_EHI_DID_RESET)
+                        ehc->i.action |= ATA_EH_HARDRESET;
+                else
+                        ehc->i.action |= ATA_EH_SOFTRESET;
+        }
 
         if (ata_port_nr_enabled(ap)) {
                 ata_port_printk(ap, KERN_WARNING, "failed to recover some "
diff --git a/include/linux/libata.h b/include/linux/libata.h
index a1ceb5b67b97..56971943d261 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -824,6 +824,19 @@ extern void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
         (ehi)->desc_len = 0; \
 } while (0)
 
+static inline void ata_ehi_hotplugged(struct ata_eh_info *ehi)
+{
+        if (ehi->flags & ATA_EHI_HOTPLUGGED)
+                return;
+
+        ehi->flags |= ATA_EHI_HOTPLUGGED;
+        ehi->hotplug_timestamp = jiffies;
+
+        ehi->err_mask |= AC_ERR_ATA_BUS;
+        ehi->action |= ATA_EH_SOFTRESET;
+        ehi->probe_mask |= (1 << ATA_MAX_DEVICES) - 1;
+}
+
 /*
  * qc helpers
  */