libata-link: update EH to deal with PMP links

Update ata_eh_autopsy(), ata_eh_report(),
ata_eh_revalidate_and_attach() and ata_eh_recover() to deal with PMP
links.  ata_eh_autopsy() and ata_eh_report() updates are
straightforward.  They just repeat the same operation over all
configured links.  The only change to ata_eh_revalidate_and_attach()
is avoiding calling ->cable_select() on non-host ports.

ata_eh_recover() update is more complex as it first processes all
resets and then performs the rest.  This is necessary as thawing with
some links in unknown state can be dangerous.  ehi->action is cleared
on successful recovery of a link to avoid repeating recovery due to
failures in other links.

ata_eh_recover() iterates over only PMP links if PMP is attached, and,
on failure, the failing link is returned in @failed_link instead of
disabling devices directly.  These are to integrate ata_eh_recover()
into PMP EH later.

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

1 files changed, 158 insertions, 70 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 45eb932c3935..2ddc2ed9c29d 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1578,8 +1578,8 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,
 }
 
 /**
- *      ata_eh_autopsy - analyze error and determine recovery action
- *      @link: ATA link to perform autopsy on
+ *      ata_eh_link_autopsy - analyze error and determine recovery action
+ *      @link: host link to perform autopsy on
  *
  *      Analyze why @link failed and determine which recovery actions
  *      are needed.  This function also sets more detailed AC_ERR_*
@@ -1588,7 +1588,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev, int is_io,
  *      LOCKING:
  *      Kernel thread context (may sleep).
  */
-static void ata_eh_autopsy(struct ata_link *link)
+static void ata_eh_link_autopsy(struct ata_link *link)
 {
         struct ata_port *ap = link->ap;
         struct ata_eh_context *ehc = &link->eh_context;
@@ -1680,7 +1680,25 @@ static void ata_eh_autopsy(struct ata_link *link)
 }
 
 /**
- *      ata_eh_report - report error handling to user
+ *      ata_eh_autopsy - analyze error and determine recovery action
+ *      @ap: host port to perform autopsy on
+ *
+ *      Analyze all links of @ap and determine why they failed and
+ *      which recovery actions are needed.
+ *
+ *      LOCKING:
+ *      Kernel thread context (may sleep).
+ */
+static void ata_eh_autopsy(struct ata_port *ap)
+{
+        struct ata_link *link;
+
+        __ata_port_for_each_link(link, ap)
+                ata_eh_link_autopsy(link);
+}
+
+/**
+ *      ata_eh_link_report - report error handling to user
  *      @link: ATA link EH is going on
  *
  *      Report EH to user.
@@ -1688,7 +1706,7 @@ static void ata_eh_autopsy(struct ata_link *link)
  *      LOCKING:
  *      None.
  */
-static void ata_eh_report(struct ata_link *link)
+static void ata_eh_link_report(struct ata_link *link)
 {
         struct ata_port *ap = link->ap;
         struct ata_eh_context *ehc = &link->eh_context;
@@ -1767,6 +1785,23 @@ static void ata_eh_report(struct ata_link *link)
         }
 }
 
+/**
+ *      ata_eh_report - report error handling to user
+ *      @ap: ATA port to report EH about
+ *
+ *      Report EH to user.
+ *
+ *      LOCKING:
+ *      None.
+ */
+static void ata_eh_report(struct ata_port *ap)
+{
+        struct ata_link *link;
+
+        __ata_port_for_each_link(link, ap)
+                ata_eh_link_report(link);
+}
+
 static int ata_do_reset(struct ata_link *link, ata_reset_fn_t reset,
                         unsigned int *classes, unsigned long deadline)
 {
@@ -2036,7 +2071,8 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
         }
 
         /* PDIAG- should have been released, ask cable type if post-reset */
-        if ((ehc->i.flags & ATA_EHI_DID_RESET) && ap->ops->cable_detect)
+        if (ata_is_host_link(link) && ap->ops->cable_detect &&
+            (ehc->i.flags & ATA_EHI_DID_RESET))
                 ap->cbl = ap->ops->cable_detect(ap);
 
         /* Configure new devices forward such that user doesn't see
@@ -2110,7 +2146,7 @@ static int ata_eh_skip_recovery(struct ata_link *link)
         return 1;
 }
 
-static void ata_eh_handle_dev_fail(struct ata_device *dev, int err)
+static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 {
         struct ata_eh_context *ehc = &dev->link->eh_context;
 
@@ -2151,12 +2187,16 @@ static void ata_eh_handle_dev_fail(struct ata_device *dev, int err)
                         ehc->did_probe_mask |= (1 << dev->devno);
                         ehc->i.action |= ATA_EH_SOFTRESET;
                 }
+
+                return 1;
         } 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;
+
+                return 0;
         }
 }
 
@@ -2167,12 +2207,13 @@ static void ata_eh_handle_dev_fail(struct ata_device *dev, int err)
  *      @softreset: softreset method (can be NULL)
  *      @hardreset: hardreset method (can be NULL)
  *      @postreset: postreset method (can be NULL)
+ *      @r_failed_link: out parameter for failed link
  *
  *      This is the alpha and omega, eum and yang, heart and soul of
  *      libata exception handling.  On entry, actions required to
- *      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
+ *      recover each link and hotplug requests are recorded in the
+ *      link's eh_context.  This function executes all the operations
+ *      with appropriate retrials and fallbacks to resurrect failed
  *      devices, detach goners and greet newcomers.
  *
  *      LOCKING:
@@ -2183,102 +2224,139 @@ static void ata_eh_handle_dev_fail(struct ata_device *dev, int err)
  */
 static int ata_eh_recover(struct ata_port *ap, ata_prereset_fn_t prereset,
                           ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
-                          ata_postreset_fn_t postreset)
+                          ata_postreset_fn_t postreset,
+                          struct ata_link **r_failed_link)
 {
-        struct ata_link *link = &ap->link;
-        struct ata_eh_context *ehc = &link->eh_context;
+        struct ata_link *link;
         struct ata_device *dev;
-        int rc;
+        int nr_failed_devs, nr_disabled_devs;
+        int reset, rc;
 
         DPRINTK("ENTER\n");
 
         /* prep for recovery */
-        ata_link_for_each_dev(dev, link) {
-                ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
+        ata_port_for_each_link(link, ap) {
+                struct ata_eh_context *ehc = &link->eh_context;
 
-                /* collect port action mask recorded in dev actions */
-                ehc->i.action |=
-                        ehc->i.dev_action[dev->devno] & ~ATA_EH_PERDEV_MASK;
-                ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
-
-                /* process hotplug request */
-                if (dev->flags & ATA_DFLAG_DETACH)
-                        ata_eh_detach_dev(dev);
+                ata_link_for_each_dev(dev, link) {
+                        ehc->tries[dev->devno] = ATA_EH_DEV_TRIES;
 
-                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;
+                        /* collect port action mask recorded in dev actions */
+                        ehc->i.action |= ehc->i.dev_action[dev->devno] &
+                                         ~ATA_EH_PERDEV_MASK;
+                        ehc->i.dev_action[dev->devno] &= ATA_EH_PERDEV_MASK;
+
+                        /* 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:
         rc = 0;
+        nr_failed_devs = 0;
+        nr_disabled_devs = 0;
+        reset = 0;
 
         /* if UNLOADING, finish immediately */
         if (ap->pflags & ATA_PFLAG_UNLOADING)
                 goto out;
 
-        /* skip EH if possible. */
-        if (ata_eh_skip_recovery(link))
-                ehc->i.action = 0;
+        /* prep for EH */
+        ata_port_for_each_link(link, ap) {
+                struct ata_eh_context *ehc = &link->eh_context;
 
-        ata_link_for_each_dev(dev, link)
-                ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
+                /* skip EH if possible. */
+                if (ata_eh_skip_recovery(link))
+                        ehc->i.action = 0;
+
+                /* do we need to reset? */
+                if (ehc->i.action & ATA_EH_RESET_MASK)
+                        reset = 1;
+
+                ata_link_for_each_dev(dev, link)
+                        ehc->classes[dev->devno] = ATA_DEV_UNKNOWN;
+        }
 
         /* reset */
-        if (ehc->i.action & ATA_EH_RESET_MASK) {
+        if (reset) {
                 ata_eh_freeze_port(ap);
 
-                rc = ata_eh_reset(link, ata_link_nr_vacant(link), prereset,
-                                  softreset, hardreset, postreset);
-                if (rc) {
-                        ata_link_printk(link, KERN_ERR,
-                                        "reset failed, giving up\n");
-                        goto out;
+                ata_port_for_each_link(link, ap) {
+                        struct ata_eh_context *ehc = &link->eh_context;
+
+                        if (!(ehc->i.action & ATA_EH_RESET_MASK))
+                                continue;
+
+                        rc = ata_eh_reset(link, ata_link_nr_vacant(link),
+                                          prereset, softreset, hardreset,
+                                          postreset);
+                        if (rc) {
+                                ata_link_printk(link, KERN_ERR,
+                                                "reset failed, giving up\n");
+                                goto out;
+                        }
                 }
 
                 ata_eh_thaw_port(ap);
         }
 
-        /* revalidate existing devices and attach new ones */
-        rc = ata_eh_revalidate_and_attach(link, &dev);
-        if (rc)
-                goto dev_fail;
+        /* the rest */
+        ata_port_for_each_link(link, ap) {
+                struct ata_eh_context *ehc = &link->eh_context;
 
-        /* configure transfer mode if necessary */
-        if (ehc->i.flags & ATA_EHI_SETMODE) {
-                rc = ata_set_mode(link, &dev);
+                /* revalidate existing devices and attach new ones */
+                rc = ata_eh_revalidate_and_attach(link, &dev);
                 if (rc)
                         goto dev_fail;
-                ehc->i.flags &= ~ATA_EHI_SETMODE;
-        }
 
-        goto out;
+                /* configure transfer mode if necessary */
+                if (ehc->i.flags & ATA_EHI_SETMODE) {
+                        rc = ata_set_mode(link, &dev);
+                        if (rc)
+                                goto dev_fail;
+                        ehc->i.flags &= ~ATA_EHI_SETMODE;
+                }
+
+                /* this link is okay now */
+                ehc->i.flags = 0;
+                continue;
 
- dev_fail:
-        ata_eh_handle_dev_fail(dev, rc);
+        dev_fail:
+                nr_failed_devs++;
+                if (ata_eh_handle_dev_fail(dev, rc))
+                        nr_disabled_devs++;
 
-        if (ata_link_nr_enabled(link)) {
-                ata_link_printk(link, KERN_WARNING, "failed to recover some "
-                                "devices, retrying in 5 secs\n");
-                ssleep(5);
-        } else {
-                /* no device left, repeat fast */
-                msleep(500);
+                if (ap->pflags & ATA_PFLAG_FROZEN)
+                        break;
         }
 
-        goto retry;
+        if (nr_failed_devs) {
+                if (nr_failed_devs != nr_disabled_devs) {
+                        ata_port_printk(ap, KERN_WARNING, "failed to recover "
+                                        "some devices, retrying in 5 secs\n");
+                        ssleep(5);
+                } else {
+                        /* no device left to recover, repeat fast */
+                        msleep(500);
+                }
 
- out:
-        if (rc) {
-                ata_link_for_each_dev(dev, link);
-                        ata_dev_disable(dev);
+                goto retry;
         }
 
+ out:
+        if (rc && r_failed_link)
+                *r_failed_link = link;
+
         DPRINTK("EXIT, rc=%d\n", rc);
         return rc;
 }
@@ -2342,9 +2420,19 @@ void ata_do_eh(struct ata_port *ap, ata_prereset_fn_t prereset,
                ata_reset_fn_t softreset, ata_reset_fn_t hardreset,
                ata_postreset_fn_t postreset)
 {
-        ata_eh_autopsy(&ap->link);
-        ata_eh_report(&ap->link);
-        ata_eh_recover(ap, prereset, softreset, hardreset, postreset);
+        struct ata_device *dev;
+        int rc;
+
+        ata_eh_autopsy(ap);
+        ata_eh_report(ap);
+
+        rc = ata_eh_recover(ap, prereset, softreset, hardreset, postreset,
+                            NULL);
+        if (rc) {
+                ata_link_for_each_dev(dev, &ap->link)
+                        ata_dev_disable(dev);
+        }
+
         ata_eh_finish(ap);
 }