[SCSI] libsas: let libata recover links that fail to transmit initial sig-fis

libsas fails to discover all sata devices in the domain.  If a device fails
negotiation and does not transmit a signature fis the link needs recovery.
libata already understands how to manage slow to come up links, so treat these
conditions as ata device attach events for the purposes of creating an
ata_port.  This allows libata to manage retrying link bring up.

Rediscovery is modified to be careful about checking changes in dev_type.  It
looks like libsas leaks old devices if the sas address changes, but that's a
fix for another patch.

Acked-by: Jack Wang <jack_wang@usish.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 99 insertions, 79 deletions

diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c
index 4b2ecd35dc5a..7e2d3c4c6171 100644
--- a/drivers/scsi/libsas/sas_expander.c
+++ b/drivers/scsi/libsas/sas_expander.c
@@ -183,13 +183,27 @@ static char sas_route_char(struct domain_device *dev, struct ex_phy *phy)
         }
 }
 
-static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
-                           void *disc_resp)
+static enum sas_dev_type to_dev_type(struct discover_resp *dr)
 {
+        /* This is detecting a failure to transmit initial dev to host
+         * FIS as described in section J.5 of sas-2 r16
+         */
+        if (dr->attached_dev_type == NO_DEVICE && dr->attached_sata_dev &&
+            dr->linkrate >= SAS_LINK_RATE_1_5_GBPS)
+                return SATA_PENDING;
+        else
+                return dr->attached_dev_type;
+}
+
+static void sas_set_ex_phy(struct domain_device *dev, int phy_id, void *rsp)
+{
+        enum sas_dev_type dev_type;
+        enum sas_linkrate linkrate;
+        u8 sas_addr[SAS_ADDR_SIZE];
+        struct smp_resp *resp = rsp;
+        struct discover_resp *dr = &resp->disc;
         struct expander_device *ex = &dev->ex_dev;
         struct ex_phy *phy = &ex->ex_phy[phy_id];
-        struct smp_resp *resp = disc_resp;
-        struct discover_resp *dr = &resp->disc;
         struct sas_rphy *rphy = dev->rphy;
         bool new_phy = !phy->phy;
         char *type;
@@ -213,8 +227,13 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
                 break;
         }
 
+        /* check if anything important changed to squelch debug */
+        dev_type = phy->attached_dev_type;
+        linkrate  = phy->linkrate;
+        memcpy(sas_addr, phy->attached_sas_addr, SAS_ADDR_SIZE);
+
+        phy->attached_dev_type = to_dev_type(dr);
         phy->phy_id = phy_id;
-        phy->attached_dev_type = dr->attached_dev_type;
         phy->linkrate = dr->linkrate;
         phy->attached_sata_host = dr->attached_sata_host;
         phy->attached_sata_dev  = dr->attached_sata_dev;
@@ -229,7 +248,7 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
         phy->last_da_index = -1;
 
         phy->phy->identify.sas_address = SAS_ADDR(phy->attached_sas_addr);
-        phy->phy->identify.device_type = phy->attached_dev_type;
+        phy->phy->identify.device_type = dr->attached_dev_type;
         phy->phy->identify.initiator_port_protocols = phy->attached_iproto;
         phy->phy->identify.target_port_protocols = phy->attached_tproto;
         phy->phy->identify.phy_identifier = phy_id;
@@ -246,6 +265,9 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
                 }
 
         switch (phy->attached_dev_type) {
+        case SATA_PENDING:
+                type = "stp pending";
+                break;
         case NO_DEVICE:
                 type = "no device";
                 break;
@@ -270,6 +292,16 @@ static void sas_set_ex_phy(struct domain_device *dev, int phy_id,
                 type = "unknown";
         }
 
+        /* this routine is polled by libata error recovery so filter
+         * unimportant messages
+         */
+        if (new_phy || phy->attached_dev_type != dev_type ||
+            phy->linkrate != linkrate ||
+            SAS_ADDR(phy->attached_sas_addr) != SAS_ADDR(sas_addr))
+                /* pass */;
+        else
+                return;
+
         SAS_DPRINTK("ex %016llx phy%02d:%c:%X attached: %016llx (%s)\n",
                     SAS_ADDR(dev->sas_addr), phy->phy_id,
                     sas_route_char(dev, phy), phy->linkrate,
@@ -304,50 +336,25 @@ struct domain_device *sas_ex_to_ata(struct domain_device *ex_dev, int phy_id)
 static int sas_ex_phy_discover_helper(struct domain_device *dev, u8 *disc_req,
                                       u8 *disc_resp, int single)
 {
-        struct domain_device *ata_dev = sas_ex_to_ata(dev, single);
-        int i, res;
+        struct discover_resp *dr;
+        int res;
 
         disc_req[9] = single;
-        for (i = 1 ; i < 3; i++) {
-                struct discover_resp *dr;
 
-                res = smp_execute_task(dev, disc_req, DISCOVER_REQ_SIZE,
-                                       disc_resp, DISCOVER_RESP_SIZE);
-                if (res)
-                        return res;
-                dr = &((struct smp_resp *)disc_resp)->disc;
-                if (memcmp(dev->sas_addr, dr->attached_sas_addr,
-                          SAS_ADDR_SIZE) == 0) {
-                        sas_printk("Found loopback topology, just ignore it!\n");
-                        return 0;
-                }
-
-                /* This is detecting a failure to transmit initial
-                 * dev to host FIS as described in section J.5 of
-                 * sas-2 r16
-                 */
-                if (!(dr->attached_dev_type == 0 &&
-                      dr->attached_sata_dev))
-                        break;
-
-                /* In order to generate the dev to host FIS, we send a
-                 * link reset to the expander port.  If a device was
-                 * previously detected on this port we ask libata to
-                 * manage the reset and link recovery.
-                 */
-                if (ata_dev) {
-                        sas_ata_schedule_reset(ata_dev);
-                        break;
-                }
-                sas_smp_phy_control(dev, single, PHY_FUNC_LINK_RESET, NULL);
-                /* Wait for the reset to trigger the negotiation */
-                msleep(500);
+        res = smp_execute_task(dev, disc_req, DISCOVER_REQ_SIZE,
+                               disc_resp, DISCOVER_RESP_SIZE);
+        if (res)
+                return res;
+        dr = &((struct smp_resp *)disc_resp)->disc;
+        if (memcmp(dev->sas_addr, dr->attached_sas_addr, SAS_ADDR_SIZE) == 0) {
+                sas_printk("Found loopback topology, just ignore it!\n");
+                return 0;
         }
         sas_set_ex_phy(dev, single, disc_resp);
         return 0;
 }
 
-static int sas_ex_phy_discover(struct domain_device *dev, int single)
+int sas_ex_phy_discover(struct domain_device *dev, int single)
 {
         struct expander_device *ex = &dev->ex_dev;
         int  res = 0;
@@ -652,9 +659,8 @@ int sas_smp_get_phy_events(struct sas_phy *phy)
 #define RPS_REQ_SIZE  16
 #define RPS_RESP_SIZE 60
 
-static int sas_get_report_phy_sata(struct domain_device *dev,
-                                          int phy_id,
-                                          struct smp_resp *rps_resp)
+int sas_get_report_phy_sata(struct domain_device *dev, int phy_id,
+                            struct smp_resp *rps_resp)
 {
         int res;
         u8 *rps_req = alloc_smp_req(RPS_REQ_SIZE);
@@ -764,21 +770,9 @@ static struct domain_device *sas_ex_discover_end_dev(
 
 #ifdef CONFIG_SCSI_SAS_ATA
         if ((phy->attached_tproto & SAS_PROTOCOL_STP) || phy->attached_sata_dev) {
-                child->dev_type = SATA_DEV;
-                if (phy->attached_tproto & SAS_PROTOCOL_STP)
-                        child->tproto = phy->attached_tproto;
-                if (phy->attached_sata_dev)
-                        child->tproto |= SATA_DEV;
-                res = sas_get_report_phy_sata(parent, phy_id,
-                                              &child->sata_dev.rps_resp);
-                if (res) {
-                        SAS_DPRINTK("report phy sata to %016llx:0x%x returned "
-                                    "0x%x\n", SAS_ADDR(parent->sas_addr),
-                                    phy_id, res);
+                res = sas_get_ata_info(child, phy);
+                if (res)
                         goto out_free;
-                }
-                memcpy(child->frame_rcvd, &child->sata_dev.rps_resp.rps.fis,
-                       sizeof(struct dev_to_host_fis));
 
                 rphy = sas_end_device_alloc(phy->port);
                 if (unlikely(!rphy))
@@ -993,7 +987,8 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
 
         if (ex_phy->attached_dev_type != SAS_END_DEV &&
             ex_phy->attached_dev_type != FANOUT_DEV &&
-            ex_phy->attached_dev_type != EDGE_DEV) {
+            ex_phy->attached_dev_type != EDGE_DEV &&
+            ex_phy->attached_dev_type != SATA_PENDING) {
                 SAS_DPRINTK("unknown device type(0x%x) attached to ex %016llx "
                             "phy 0x%x\n", ex_phy->attached_dev_type,
                             SAS_ADDR(dev->sas_addr),
@@ -1019,6 +1014,7 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id)
 
         switch (ex_phy->attached_dev_type) {
         case SAS_END_DEV:
+        case SATA_PENDING:
                 child = sas_ex_discover_end_dev(dev, phy_id);
                 break;
         case FANOUT_DEV:
@@ -1688,8 +1684,8 @@ static int sas_get_phy_change_count(struct domain_device *dev,
         return res;
 }
 
-int sas_get_phy_attached_sas_addr(struct domain_device *dev, int phy_id,
-                                  u8 *attached_sas_addr)
+static int sas_get_phy_attached_dev(struct domain_device *dev, int phy_id,
+                                    u8 *sas_addr, enum sas_dev_type *type)
 {
         int res;
         struct smp_resp *disc_resp;
@@ -1701,10 +1697,11 @@ int sas_get_phy_attached_sas_addr(struct domain_device *dev, int phy_id,
         dr = &disc_resp->disc;
 
         res = sas_get_phy_discover(dev, phy_id, disc_resp);
-        if (!res) {
-                memcpy(attached_sas_addr,disc_resp->disc.attached_sas_addr,8);
-                if (dr->attached_dev_type == 0)
-                        memset(attached_sas_addr, 0, 8);
+        if (res == 0) {
+                memcpy(sas_addr, disc_resp->disc.attached_sas_addr, 8);
+                *type = to_dev_type(dr);
+                if (*type == 0)
+                        memset(sas_addr, 0, 8);
         }
         kfree(disc_resp);
         return res;
@@ -1953,39 +1950,62 @@ out:
         return res;
 }
 
+static bool dev_type_flutter(enum sas_dev_type new, enum sas_dev_type old)
+{
+        if (old == new)
+                return true;
+
+        /* treat device directed resets as flutter, if we went
+         * SAS_END_DEV to SATA_PENDING the link needs recovery
+         */
+        if ((old == SATA_PENDING && new == SAS_END_DEV) ||
+            (old == SAS_END_DEV && new == SATA_PENDING))
+                return true;
+
+        return false;
+}
+
 static int sas_rediscover_dev(struct domain_device *dev, int phy_id, bool last)
 {
         struct expander_device *ex = &dev->ex_dev;
         struct ex_phy *phy = &ex->ex_phy[phy_id];
-        u8 attached_sas_addr[8];
+        enum sas_dev_type type = NO_DEVICE;
+        u8 sas_addr[8];
         int res;
 
-        res = sas_get_phy_attached_sas_addr(dev, phy_id, attached_sas_addr);
+        res = sas_get_phy_attached_dev(dev, phy_id, sas_addr, &type);
         switch (res) {
         case SMP_RESP_NO_PHY:
                 phy->phy_state = PHY_NOT_PRESENT;
                 sas_unregister_devs_sas_addr(dev, phy_id, last);
-                goto out; break;
+                return res;
         case SMP_RESP_PHY_VACANT:
                 phy->phy_state = PHY_VACANT;
                 sas_unregister_devs_sas_addr(dev, phy_id, last);
-                goto out; break;
+                return res;
         case SMP_RESP_FUNC_ACC:
                 break;
         }
 
-        if (SAS_ADDR(attached_sas_addr) == 0) {
+        if (SAS_ADDR(sas_addr) == 0) {
                 phy->phy_state = PHY_EMPTY;
                 sas_unregister_devs_sas_addr(dev, phy_id, last);
-        } else if (SAS_ADDR(attached_sas_addr) ==
-                   SAS_ADDR(phy->attached_sas_addr)) {
-                SAS_DPRINTK("ex %016llx phy 0x%x broadcast flutter\n",
-                            SAS_ADDR(dev->sas_addr), phy_id);
+                return res;
+        } else if (SAS_ADDR(sas_addr) == SAS_ADDR(phy->attached_sas_addr) &&
+                   dev_type_flutter(type, phy->attached_dev_type)) {
+                struct domain_device *ata_dev = sas_ex_to_ata(dev, phy_id);
+                char *action = "";
+
                 sas_ex_phy_discover(dev, phy_id);
-        } else
-                res = sas_discover_new(dev, phy_id);
-out:
-        return res;
+
+                if (ata_dev && phy->attached_dev_type == SATA_PENDING)
+                        action = ", needs recovery";
+                SAS_DPRINTK("ex %016llx phy 0x%x broadcast flutter%s\n",
+                            SAS_ADDR(dev->sas_addr), phy_id, action);
+                return res;
+        }
+
+        return sas_discover_new(dev, phy_id);
 }
 
 /**