firewire: Introduce a retry mechanism for reconnects and logins.

Sometimes we reconnect too soon, sometimes too late.  Adding a retry
mechanism make the reconnect step much more robust.

Signed-off-by: Kristian Høgsberg <krh@redhat.com>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

1 files changed, 109 insertions, 71 deletions

diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index c196333e1de9..432c35aefc12 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -62,7 +62,8 @@ struct sbp2_device {
         /* Timer for flushing ORBs. */
         struct timer_list orb_timer;
 
-        struct work_struct work;
+        int retries;
+        struct delayed_work work;
         struct Scsi_Host *scsi_host;
 };
 
@@ -511,6 +512,75 @@ static int sbp2_agent_reset(struct fw_unit *unit)
 
 static int add_scsi_devices(struct fw_unit *unit);
 static void remove_scsi_devices(struct fw_unit *unit);
+static void sbp2_reconnect(struct work_struct *work);
+
+static void sbp2_login(struct work_struct *work)
+{
+        struct sbp2_device *sd =
+                container_of(work, struct sbp2_device, work.work);
+        struct fw_unit *unit = sd->unit;
+        struct fw_device *device = fw_device(unit->device.parent);
+        struct sbp2_login_response response;
+        int generation, node_id, local_node_id, lun, retval;
+
+        /* FIXME: Make this work for multi-lun devices. */
+        lun = 0;
+
+        generation    = device->card->generation;
+        node_id       = device->node->node_id;
+        local_node_id = device->card->local_node->node_id;
+
+        if (sbp2_send_management_orb(unit, node_id, generation,
+                                     SBP2_LOGIN_REQUEST, lun, &response) < 0) {
+                if (sd->retries++ < 5) {
+                        fw_error("login attempt %d for %s failed, "
+                                 "rescheduling\n",
+                                 sd->retries, unit->device.bus_id);
+                        schedule_delayed_work(&sd->work, DIV_ROUND_UP(HZ, 5));
+                } else {
+                        fw_error("failed to login to %s\n",
+                                 unit->device.bus_id);
+                        remove_scsi_devices(unit);
+                }
+                return;
+        }
+
+        sd->generation   = generation;
+        sd->node_id      = node_id;
+        sd->address_high = local_node_id << 16;
+
+        /* Get command block agent offset and login id. */
+        sd->command_block_agent_address =
+                ((u64) response.command_block_agent.high << 32) |
+                response.command_block_agent.low;
+        sd->login_id = login_response_get_login_id(response);
+
+        fw_notify("logged in to sbp2 unit %s\n", unit->device.bus_id);
+        fw_notify(" - management_agent_address: 0x%012llx\n",
+                  (unsigned long long) sd->management_agent_address);
+        fw_notify(" - command_block_agent_address: 0x%012llx\n",
+                  (unsigned long long) sd->command_block_agent_address);
+        fw_notify(" - status write address: 0x%012llx\n",
+                  (unsigned long long) sd->address_handler.offset);
+
+#if 0
+        /* FIXME: The linux1394 sbp2 does this last step. */
+        sbp2_set_busy_timeout(scsi_id);
+#endif
+
+        INIT_DELAYED_WORK(&sd->work, sbp2_reconnect);
+        sbp2_agent_reset(unit);
+
+        retval = add_scsi_devices(unit);
+        if (retval < 0) {
+                sbp2_send_management_orb(unit, sd->node_id, sd->generation,
+                                         SBP2_LOGOUT_REQUEST, sd->login_id,
+                                         NULL);
+                /* Set this back to sbp2_login so we fall back and
+                 * retry login on bus reset. */
+                INIT_DELAYED_WORK(&sd->work, sbp2_login);
+        }
+}
 
 static int sbp2_probe(struct device *dev)
 {
@@ -518,9 +588,7 @@ static int sbp2_probe(struct device *dev)
         struct fw_device *device = fw_device(unit->device.parent);
         struct sbp2_device *sd;
         struct fw_csr_iterator ci;
-        int i, key, value, lun, retval;
-        int node_id, generation, local_node_id;
-        struct sbp2_login_response response;
+        int i, key, value;
         u32 model, firmware_revision;
 
         sd = kzalloc(sizeof *sd, GFP_KERNEL);
@@ -586,58 +654,10 @@ static int sbp2_probe(struct device *dev)
                           unit->device.bus_id,
                           sd->workarounds, firmware_revision, model);
 
-        /* FIXME: Make this work for multi-lun devices. */
-        lun = 0;
-
-        generation    = device->card->generation;
-        node_id       = device->node->node_id;
-        local_node_id = device->card->local_node->node_id;
-
-        /* FIXME: We should probably do this from a keventd callback
-         * and handle retries by rescheduling the work. */
-        if (sbp2_send_management_orb(unit, node_id, generation,
-                                     SBP2_LOGIN_REQUEST, lun, &response) < 0) {
-                fw_core_remove_address_handler(&sd->address_handler);
-                del_timer_sync(&sd->orb_timer);
-                kfree(sd);
-                return -EBUSY;
-        }
-
-        sd->generation   = generation;
-        sd->node_id      = node_id;
-        sd->address_high = local_node_id << 16;
-
-        /* Get command block agent offset and login id. */
-        sd->command_block_agent_address =
-                ((u64) response.command_block_agent.high << 32) |
-                response.command_block_agent.low;
-        sd->login_id = login_response_get_login_id(response);
-
-        fw_notify("logged in to sbp2 unit %s\n", unit->device.bus_id);
-        fw_notify(" - management_agent_address: 0x%012llx\n",
-                  (unsigned long long) sd->management_agent_address);
-        fw_notify(" - command_block_agent_address: 0x%012llx\n",
-                  (unsigned long long) sd->command_block_agent_address);
-        fw_notify(" - status write address: 0x%012llx\n",
-                  (unsigned long long) sd->address_handler.offset);
-
-#if 0
-        /* FIXME: The linux1394 sbp2 does this last step. */
-        sbp2_set_busy_timeout(scsi_id);
-#endif
-
-        sbp2_agent_reset(unit);
-
-        retval = add_scsi_devices(unit);
-        if (retval < 0) {
-                sbp2_send_management_orb(unit, sd->node_id, sd->generation,
-                                         SBP2_LOGOUT_REQUEST, sd->login_id,
-                                         NULL);
-                fw_core_remove_address_handler(&sd->address_handler);
-                del_timer_sync(&sd->orb_timer);
-                kfree(sd);
-                return retval;
-        }
+        /* We schedule work to do the login so we can easily
+         * reschedule retries. */
+        INIT_DELAYED_WORK(&sd->work, sbp2_login);
+        schedule_delayed_work(&sd->work, 0);
 
         return 0;
 }
@@ -663,28 +683,41 @@ static int sbp2_remove(struct device *dev)
 
 static void sbp2_reconnect(struct work_struct *work)
 {
-        struct sbp2_device *sd = container_of(work, struct sbp2_device, work);
+        struct sbp2_device *sd =
+                container_of(work, struct sbp2_device, work.work);
         struct fw_unit *unit = sd->unit;
         struct fw_device *device = fw_device(unit->device.parent);
         int generation, node_id, local_node_id;
 
-        fw_notify("in sbp2_reconnect, reconnecting to unit %s\n",
-                  unit->device.bus_id);
-
         generation    = device->card->generation;
         node_id       = device->node->node_id;
         local_node_id = device->card->local_node->node_id;
 
-        sbp2_send_management_orb(unit, node_id, generation,
-                                 SBP2_RECONNECT_REQUEST, sd->login_id, NULL);
-
-        /* FIXME: handle reconnect failures. */
-
-        sbp2_cancel_orbs(unit);
+        if (sbp2_send_management_orb(unit, node_id, generation,
+                                     SBP2_RECONNECT_REQUEST,
+                                     sd->login_id, NULL) < 0) {
+                if (sd->retries++ < 5) {
+                        fw_error("reconnect attempt %d for %s failed, "
+                                 "rescheduling\n",
+                                 sd->retries, unit->device.bus_id);
+                } else {
+                        fw_error("failed to reconnect to %s\n",
+                                 unit->device.bus_id);
+                        /* Fall back and try to log in again. */
+                        sd->retries = 0;
+                        INIT_DELAYED_WORK(&sd->work, sbp2_login);
+                }
+                schedule_delayed_work(&sd->work, DIV_ROUND_UP(HZ, 5));
+                return;
+        }
 
         sd->generation   = generation;
         sd->node_id      = node_id;
         sd->address_high = local_node_id << 16;
+
+        fw_notify("reconnected to unit %s\n", unit->device.bus_id);
+        sbp2_agent_reset(unit);
+        sbp2_cancel_orbs(unit);
 }
 
 static void sbp2_update(struct fw_unit *unit)
@@ -692,10 +725,9 @@ static void sbp2_update(struct fw_unit *unit)
         struct fw_device *device = fw_device(unit->device.parent);
         struct sbp2_device *sd = unit->device.driver_data;
 
+        sd->retries = 0;
         fw_device_enable_phys_dma(device);
-
-        INIT_WORK(&sd->work, sbp2_reconnect);
-        schedule_work(&sd->work);
+        schedule_delayed_work(&sd->work, 0);
 }
 
 #define SBP2_UNIT_SPEC_ID_ENTRY 0x0000609e
@@ -1056,6 +1088,9 @@ static int add_scsi_devices(struct fw_unit *unit)
         struct sbp2_device *sd = unit->device.driver_data;
         int retval, lun;
 
+        if (sd->scsi_host != NULL)
+                return 0;
+
         sd->scsi_host = scsi_host_alloc(&scsi_driver_template,
                                         sizeof(unsigned long));
         if (sd->scsi_host == NULL) {
@@ -1088,8 +1123,11 @@ static void remove_scsi_devices(struct fw_unit *unit)
 {
         struct sbp2_device *sd = unit->device.driver_data;
 
-        scsi_remove_host(sd->scsi_host);
-        scsi_host_put(sd->scsi_host);
+        if (sd->scsi_host != NULL) {
+                scsi_remove_host(sd->scsi_host);
+                scsi_host_put(sd->scsi_host);
+        }
+        sd->scsi_host = NULL;
 }
 
 MODULE_AUTHOR("Kristian Hoegsberg <krh@bitplanet.net>");