1 files changed, 79 insertions, 8 deletions

diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 8147a8386370..ce2ef0475339 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -82,6 +82,10 @@ enum {
         ATA_EH_FASTDRAIN_INTERVAL       =  3000,
 
         ATA_EH_UA_TRIES                 = 5,
+
+        /* probe speed down parameters, see ata_eh_schedule_probe() */
+        ATA_EH_PROBE_TRIAL_INTERVAL     = 60000,        /* 1 min */
+        ATA_EH_PROBE_TRIALS             = 2,
 };
 
 /* The following table determines how we sequence resets.  Each entry
@@ -1176,6 +1180,32 @@ void ata_eh_qc_retry(struct ata_queued_cmd *qc)
 }
 
 /**
+ *      ata_dev_disable - disable ATA device
+ *      @dev: ATA device to disable
+ *
+ *      Disable @dev.
+ *
+ *      Locking:
+ *      EH context.
+ */
+void ata_dev_disable(struct ata_device *dev)
+{
+        if (!ata_dev_enabled(dev))
+                return;
+
+        if (ata_msg_drv(dev->link->ap))
+                ata_dev_printk(dev, KERN_WARNING, "disabled\n");
+        ata_acpi_on_disable(dev);
+        ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO0 | ATA_DNXFER_QUIET);
+        dev->class++;
+
+        /* From now till the next successful probe, ering is used to
+         * track probe failures.  Clear accumulated device error info.
+         */
+        ata_ering_clear(&dev->ering);
+}
+
+/**
  *      ata_eh_detach_dev - detach ATA device
  *      @dev: ATA device to detach
  *
@@ -1849,7 +1879,7 @@ static unsigned int ata_eh_speed_down(struct ata_device *dev,
         /* speed down? */
         if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
                 /* speed down SATA link speed if possible */
-                if (sata_down_spd_limit(link) == 0) {
+                if (sata_down_spd_limit(link, 0) == 0) {
                         action |= ATA_EH_RESET;
                         goto done;
                 }
@@ -2601,11 +2631,11 @@ int ata_eh_reset(struct ata_link *link, int classify,
         }
 
         if (try == max_tries - 1) {
-                sata_down_spd_limit(link);
+                sata_down_spd_limit(link, 0);
                 if (slave)
-                        sata_down_spd_limit(slave);
+                        sata_down_spd_limit(slave, 0);
         } else if (rc == -EPIPE)
-                sata_down_spd_limit(failed_link);
+                sata_down_spd_limit(failed_link, 0);
 
         if (hardreset)
                 reset = hardreset;
@@ -2744,6 +2774,8 @@ static int ata_eh_revalidate_and_attach(struct ata_link *link,
                                                      readid_flags, dev->id);
                         switch (rc) {
                         case 0:
+                                /* clear error info accumulated during probe */
+                                ata_ering_clear(&dev->ering);
                                 new_mask |= 1 << dev->devno;
                                 break;
                         case -ENOENT:
@@ -2947,9 +2979,24 @@ static int ata_eh_skip_recovery(struct ata_link *link)
         return 1;
 }
 
+static int ata_count_probe_trials_cb(struct ata_ering_entry *ent, void *void_arg)
+{
+        u64 interval = msecs_to_jiffies(ATA_EH_PROBE_TRIAL_INTERVAL);
+        u64 now = get_jiffies_64();
+        int *trials = void_arg;
+
+        if (ent->timestamp < now - min(now, interval))
+                return -1;
+
+        (*trials)++;
+        return 0;
+}
+
 static int ata_eh_schedule_probe(struct ata_device *dev)
 {
         struct ata_eh_context *ehc = &dev->link->eh_context;
+        struct ata_link *link = ata_dev_phys_link(dev);
+        int trials = 0;
 
         if (!(ehc->i.probe_mask & (1 << dev->devno)) ||
             (ehc->did_probe_mask & (1 << dev->devno)))
@@ -2962,6 +3009,25 @@ static int ata_eh_schedule_probe(struct ata_device *dev)
         ehc->saved_xfer_mode[dev->devno] = 0;
         ehc->saved_ncq_enabled &= ~(1 << dev->devno);
 
+        /* Record and count probe trials on the ering.  The specific
+         * error mask used is irrelevant.  Because a successful device
+         * detection clears the ering, this count accumulates only if
+         * there are consecutive failed probes.
+         *
+         * If the count is equal to or higher than ATA_EH_PROBE_TRIALS
+         * in the last ATA_EH_PROBE_TRIAL_INTERVAL, link speed is
+         * forced to 1.5Gbps.
+         *
+         * This is to work around cases where failed link speed
+         * negotiation results in device misdetection leading to
+         * infinite DEVXCHG or PHRDY CHG events.
+         */
+        ata_ering_record(&dev->ering, 0, AC_ERR_OTHER);
+        ata_ering_map(&dev->ering, ata_count_probe_trials_cb, &trials);
+
+        if (trials > ATA_EH_PROBE_TRIALS)
+                sata_down_spd_limit(link, 1);
+
         return 1;
 }
 
@@ -2969,7 +3035,11 @@ static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
 {
         struct ata_eh_context *ehc = &dev->link->eh_context;
 
-        ehc->tries[dev->devno]--;
+        /* -EAGAIN from EH routine indicates retry without prejudice.
+         * The requester is responsible for ensuring forward progress.
+         */
+        if (err != -EAGAIN)
+                ehc->tries[dev->devno]--;
 
         switch (err) {
         case -ENODEV:
@@ -2979,12 +3049,13 @@ static int ata_eh_handle_dev_fail(struct ata_device *dev, int err)
                 /* give it just one more chance */
                 ehc->tries[dev->devno] = min(ehc->tries[dev->devno], 1);
         case -EIO:
-                if (ehc->tries[dev->devno] == 1 && dev->pio_mode > XFER_PIO_0) {
+                if (ehc->tries[dev->devno] == 1) {
                         /* This is the last chance, better to slow
                          * down than lose it.
                          */
-                        sata_down_spd_limit(ata_dev_phys_link(dev));
-                        ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
+                        sata_down_spd_limit(ata_dev_phys_link(dev), 0);
+                        if (dev->pio_mode > XFER_PIO_0)
+                                ata_down_xfermask_limit(dev, ATA_DNXFER_PIO);
                 }
         }