1 files changed, 303 insertions, 89 deletions

diff --git a/drivers/firewire/fw-sbp2.c b/drivers/firewire/fw-sbp2.c
index 19ece9b6d742..03069a454c07 100644
--- a/drivers/firewire/fw-sbp2.c
+++ b/drivers/firewire/fw-sbp2.c
@@ -28,14 +28,15 @@
  * and many others.
  */
 
+#include <linux/blkdev.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
 #include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/mod_devicetable.h>
-#include <linux/device.h>
 #include <linux/scatterlist.h>
-#include <linux/dma-mapping.h>
-#include <linux/blkdev.h>
 #include <linux/string.h>
 #include <linux/stringify.h>
 #include <linux/timer.h>
@@ -47,9 +48,9 @@
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
 
-#include "fw-transaction.h"
-#include "fw-topology.h"
 #include "fw-device.h"
+#include "fw-topology.h"
+#include "fw-transaction.h"
 
 /*
  * So far only bridges from Oxford Semiconductor are known to support
@@ -82,6 +83,9 @@ MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device "
  *   Avoids access beyond actual disk limits on devices with an off-by-one bug.
  *   Don't use this with devices which don't have this bug.
  *
+ * - delay inquiry
+ *   Wait extra SBP2_INQUIRY_DELAY seconds after login before SCSI inquiry.
+ *
  * - override internal blacklist
  *   Instead of adding to the built-in blacklist, use only the workarounds
  *   specified in the module load parameter.
@@ -91,6 +95,8 @@ MODULE_PARM_DESC(exclusive_login, "Exclusive login to sbp2 device "
 #define SBP2_WORKAROUND_INQUIRY_36      0x2
 #define SBP2_WORKAROUND_MODE_SENSE_8    0x4
 #define SBP2_WORKAROUND_FIX_CAPACITY    0x8
+#define SBP2_WORKAROUND_DELAY_INQUIRY   0x10
+#define SBP2_INQUIRY_DELAY              12
 #define SBP2_WORKAROUND_OVERRIDE        0x100
 
 static int sbp2_param_workarounds;
@@ -100,6 +106,7 @@ MODULE_PARM_DESC(workarounds, "Work around device bugs (default = 0"
         ", 36 byte inquiry = "    __stringify(SBP2_WORKAROUND_INQUIRY_36)
         ", skip mode page 8 = "   __stringify(SBP2_WORKAROUND_MODE_SENSE_8)
         ", fix capacity = "       __stringify(SBP2_WORKAROUND_FIX_CAPACITY)
+        ", delay inquiry = "      __stringify(SBP2_WORKAROUND_DELAY_INQUIRY)
         ", override internal blacklist = " __stringify(SBP2_WORKAROUND_OVERRIDE)
         ", or a combination)");
 
@@ -115,7 +122,6 @@ static const char sbp2_driver_name[] = "sbp2";
 struct sbp2_logical_unit {
         struct sbp2_target *tgt;
         struct list_head link;
-        struct scsi_device *sdev;
         struct fw_address_handler address_handler;
         struct list_head orb_list;
 
@@ -132,6 +138,8 @@ struct sbp2_logical_unit {
         int generation;
         int retries;
         struct delayed_work work;
+        bool has_sdev;
+        bool blocked;
 };
 
 /*
@@ -141,16 +149,18 @@ struct sbp2_logical_unit {
 struct sbp2_target {
         struct kref kref;
         struct fw_unit *unit;
+        const char *bus_id;
+        struct list_head lu_list;
 
         u64 management_agent_address;
         int directory_id;
         int node_id;
         int address_high;
-
-        unsigned workarounds;
-        struct list_head lu_list;
-
+        unsigned int workarounds;
         unsigned int mgt_orb_timeout;
+
+        int dont_block; /* counter for each logical unit */
+        int blocked;    /* ditto */
 };
 
 /*
@@ -160,7 +170,7 @@ struct sbp2_target {
  */
 #define SBP2_MIN_LOGIN_ORB_TIMEOUT      5000U   /* Timeout in ms */
 #define SBP2_MAX_LOGIN_ORB_TIMEOUT      40000U  /* Timeout in ms */
-#define SBP2_ORB_TIMEOUT                2000    /* Timeout in ms */
+#define SBP2_ORB_TIMEOUT                2000U   /* Timeout in ms */
 #define SBP2_ORB_NULL                   0x80000000
 #define SBP2_MAX_SG_ELEMENT_LENGTH      0xf000
 
@@ -297,7 +307,7 @@ struct sbp2_command_orb {
 static const struct {
         u32 firmware_revision;
         u32 model;
-        unsigned workarounds;
+        unsigned int workarounds;
 } sbp2_workarounds_table[] = {
         /* DViCO Momobay CX-1 with TSB42AA9 bridge */ {
                 .firmware_revision      = 0x002800,
@@ -305,6 +315,11 @@ static const struct {
                 .workarounds            = SBP2_WORKAROUND_INQUIRY_36 |
                                           SBP2_WORKAROUND_MODE_SENSE_8,
         },
+        /* DViCO Momobay FX-3A with TSB42AA9A bridge */ {
+                .firmware_revision      = 0x002800,
+                .model                  = 0x000000,
+                .workarounds            = SBP2_WORKAROUND_DELAY_INQUIRY,
+        },
         /* Initio bridges, actually only needed for some older ones */ {
                 .firmware_revision      = 0x000200,
                 .model                  = ~0,
@@ -501,6 +516,9 @@ sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
         unsigned int timeout;
         int retval = -ENOMEM;
 
+        if (function == SBP2_LOGOUT_REQUEST && fw_device_is_shutdown(device))
+                return 0;
+
         orb = kzalloc(sizeof(*orb), GFP_ATOMIC);
         if (orb == NULL)
                 return -ENOMEM;
@@ -553,20 +571,20 @@ sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
 
         retval = -EIO;
         if (sbp2_cancel_orbs(lu) == 0) {
-                fw_error("orb reply timed out, rcode=0x%02x\n",
-                         orb->base.rcode);
+                fw_error("%s: orb reply timed out, rcode=0x%02x\n",
+                         lu->tgt->bus_id, orb->base.rcode);
                 goto out;
         }
 
         if (orb->base.rcode != RCODE_COMPLETE) {
-                fw_error("management write failed, rcode 0x%02x\n",
-                         orb->base.rcode);
+                fw_error("%s: management write failed, rcode 0x%02x\n",
+                         lu->tgt->bus_id, orb->base.rcode);
                 goto out;
         }
 
         if (STATUS_GET_RESPONSE(orb->status) != 0 ||
             STATUS_GET_SBP_STATUS(orb->status) != 0) {
-                fw_error("error status: %d:%d\n",
+                fw_error("%s: error status: %d:%d\n", lu->tgt->bus_id,
                          STATUS_GET_RESPONSE(orb->status),
                          STATUS_GET_SBP_STATUS(orb->status));
                 goto out;
@@ -590,29 +608,158 @@ sbp2_send_management_orb(struct sbp2_logical_unit *lu, int node_id,
 
 static void
 complete_agent_reset_write(struct fw_card *card, int rcode,
-                           void *payload, size_t length, void *data)
+                           void *payload, size_t length, void *done)
 {
-        struct fw_transaction *t = data;
+        complete(done);
+}
 
-        kfree(t);
+static void sbp2_agent_reset(struct sbp2_logical_unit *lu)
+{
+        struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
+        DECLARE_COMPLETION_ONSTACK(done);
+        struct fw_transaction t;
+        static u32 z;
+
+        fw_send_request(device->card, &t, TCODE_WRITE_QUADLET_REQUEST,
+                        lu->tgt->node_id, lu->generation, device->max_speed,
+                        lu->command_block_agent_address + SBP2_AGENT_RESET,
+                        &z, sizeof(z), complete_agent_reset_write, &done);
+        wait_for_completion(&done);
+}
+
+static void
+complete_agent_reset_write_no_wait(struct fw_card *card, int rcode,
+                                   void *payload, size_t length, void *data)
+{
+        kfree(data);
 }
 
-static int sbp2_agent_reset(struct sbp2_logical_unit *lu)
+static void sbp2_agent_reset_no_wait(struct sbp2_logical_unit *lu)
 {
         struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
         struct fw_transaction *t;
-        static u32 zero;
+        static u32 z;
 
-        t = kzalloc(sizeof(*t), GFP_ATOMIC);
+        t = kmalloc(sizeof(*t), GFP_ATOMIC);
         if (t == NULL)
-                return -ENOMEM;
+                return;
 
         fw_send_request(device->card, t, TCODE_WRITE_QUADLET_REQUEST,
                         lu->tgt->node_id, lu->generation, device->max_speed,
                         lu->command_block_agent_address + SBP2_AGENT_RESET,
-                        &zero, sizeof(zero), complete_agent_reset_write, t);
+                        &z, sizeof(z), complete_agent_reset_write_no_wait, t);
+}
 
-        return 0;
+static void sbp2_set_generation(struct sbp2_logical_unit *lu, int generation)
+{
+        struct fw_card *card = fw_device(lu->tgt->unit->device.parent)->card;
+        unsigned long flags;
+
+        /* serialize with comparisons of lu->generation and card->generation */
+        spin_lock_irqsave(&card->lock, flags);
+        lu->generation = generation;
+        spin_unlock_irqrestore(&card->lock, flags);
+}
+
+static inline void sbp2_allow_block(struct sbp2_logical_unit *lu)
+{
+        /*
+         * We may access dont_block without taking card->lock here:
+         * All callers of sbp2_allow_block() and all callers of sbp2_unblock()
+         * are currently serialized against each other.
+         * And a wrong result in sbp2_conditionally_block()'s access of
+         * dont_block is rather harmless, it simply misses its first chance.
+         */
+        --lu->tgt->dont_block;
+}
+
+/*
+ * Blocks lu->tgt if all of the following conditions are met:
+ *   - Login, INQUIRY, and high-level SCSI setup of all of the target's
+ *     logical units have been finished (indicated by dont_block == 0).
+ *   - lu->generation is stale.
+ *
+ * Note, scsi_block_requests() must be called while holding card->lock,
+ * otherwise it might foil sbp2_[conditionally_]unblock()'s attempt to
+ * unblock the target.
+ */
+static void sbp2_conditionally_block(struct sbp2_logical_unit *lu)
+{
+        struct sbp2_target *tgt = lu->tgt;
+        struct fw_card *card = fw_device(tgt->unit->device.parent)->card;
+        struct Scsi_Host *shost =
+                container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
+        unsigned long flags;
+
+        spin_lock_irqsave(&card->lock, flags);
+        if (!tgt->dont_block && !lu->blocked &&
+            lu->generation != card->generation) {
+                lu->blocked = true;
+                if (++tgt->blocked == 1) {
+                        scsi_block_requests(shost);
+                        fw_notify("blocked %s\n", lu->tgt->bus_id);
+                }
+        }
+        spin_unlock_irqrestore(&card->lock, flags);
+}
+
+/*
+ * Unblocks lu->tgt as soon as all its logical units can be unblocked.
+ * Note, it is harmless to run scsi_unblock_requests() outside the
+ * card->lock protected section.  On the other hand, running it inside
+ * the section might clash with shost->host_lock.
+ */
+static void sbp2_conditionally_unblock(struct sbp2_logical_unit *lu)
+{
+        struct sbp2_target *tgt = lu->tgt;
+        struct fw_card *card = fw_device(tgt->unit->device.parent)->card;
+        struct Scsi_Host *shost =
+                container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
+        unsigned long flags;
+        bool unblock = false;
+
+        spin_lock_irqsave(&card->lock, flags);
+        if (lu->blocked && lu->generation == card->generation) {
+                lu->blocked = false;
+                unblock = --tgt->blocked == 0;
+        }
+        spin_unlock_irqrestore(&card->lock, flags);
+
+        if (unblock) {
+                scsi_unblock_requests(shost);
+                fw_notify("unblocked %s\n", lu->tgt->bus_id);
+        }
+}
+
+/*
+ * Prevents future blocking of tgt and unblocks it.
+ * Note, it is harmless to run scsi_unblock_requests() outside the
+ * card->lock protected section.  On the other hand, running it inside
+ * the section might clash with shost->host_lock.
+ */
+static void sbp2_unblock(struct sbp2_target *tgt)
+{
+        struct fw_card *card = fw_device(tgt->unit->device.parent)->card;
+        struct Scsi_Host *shost =
+                container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
+        unsigned long flags;
+
+        spin_lock_irqsave(&card->lock, flags);
+        ++tgt->dont_block;
+        spin_unlock_irqrestore(&card->lock, flags);
+
+        scsi_unblock_requests(shost);
+}
+
+static int sbp2_lun2int(u16 lun)
+{
+        struct scsi_lun eight_bytes_lun;
+
+        memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
+        eight_bytes_lun.scsi_lun[0] = (lun >> 8) & 0xff;
+        eight_bytes_lun.scsi_lun[1] = lun & 0xff;
+
+        return scsilun_to_int(&eight_bytes_lun);
 }
 
 static void sbp2_release_target(struct kref *kref)
@@ -621,26 +768,31 @@ static void sbp2_release_target(struct kref *kref)
         struct sbp2_logical_unit *lu, *next;
         struct Scsi_Host *shost =
                 container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
+        struct scsi_device *sdev;
         struct fw_device *device = fw_device(tgt->unit->device.parent);
 
-        list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
-                if (lu->sdev)
-                        scsi_remove_device(lu->sdev);
+        /* prevent deadlocks */
+        sbp2_unblock(tgt);
 
-                if (!fw_device_is_shutdown(device))
-                        sbp2_send_management_orb(lu, tgt->node_id,
-                                        lu->generation, SBP2_LOGOUT_REQUEST,
-                                        lu->login_id, NULL);
+        list_for_each_entry_safe(lu, next, &tgt->lu_list, link) {
+                sdev = scsi_device_lookup(shost, 0, 0, sbp2_lun2int(lu->lun));
+                if (sdev) {
+                        scsi_remove_device(sdev);
+                        scsi_device_put(sdev);
+                }
+                sbp2_send_management_orb(lu, tgt->node_id, lu->generation,
+                                SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
 
                 fw_core_remove_address_handler(&lu->address_handler);
                 list_del(&lu->link);
                 kfree(lu);
         }
         scsi_remove_host(shost);
-        fw_notify("released %s\n", tgt->unit->device.bus_id);
+        fw_notify("released %s\n", tgt->bus_id);
 
         put_device(&tgt->unit->device);
         scsi_host_put(shost);
+        fw_device_put(device);
 }
 
 static struct workqueue_struct *sbp2_wq;
@@ -666,33 +818,42 @@ static void sbp2_login(struct work_struct *work)
 {
         struct sbp2_logical_unit *lu =
                 container_of(work, struct sbp2_logical_unit, work.work);
-        struct Scsi_Host *shost =
-                container_of((void *)lu->tgt, struct Scsi_Host, hostdata[0]);
+        struct sbp2_target *tgt = lu->tgt;
+        struct fw_device *device = fw_device(tgt->unit->device.parent);
+        struct Scsi_Host *shost;
         struct scsi_device *sdev;
-        struct scsi_lun eight_bytes_lun;
-        struct fw_unit *unit = lu->tgt->unit;
-        struct fw_device *device = fw_device(unit->device.parent);
         struct sbp2_login_response response;
         int generation, node_id, local_node_id;
 
+        if (fw_device_is_shutdown(device))
+                goto out;
+
         generation    = device->generation;
         smp_rmb();    /* node_id must not be older than generation */
         node_id       = device->node_id;
         local_node_id = device->card->node_id;
 
+        /* If this is a re-login attempt, log out, or we might be rejected. */
+        if (lu->has_sdev)
+                sbp2_send_management_orb(lu, device->node_id, generation,
+                                SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
+
         if (sbp2_send_management_orb(lu, node_id, generation,
                                 SBP2_LOGIN_REQUEST, lu->lun, &response) < 0) {
-                if (lu->retries++ < 5)
+                if (lu->retries++ < 5) {
                         sbp2_queue_work(lu, DIV_ROUND_UP(HZ, 5));
-                else
-                        fw_error("failed to login to %s LUN %04x\n",
-                                 unit->device.bus_id, lu->lun);
+                } else {
+                        fw_error("%s: failed to login to LUN %04x\n",
+                                 tgt->bus_id, lu->lun);
+                        /* Let any waiting I/O fail from now on. */
+                        sbp2_unblock(lu->tgt);
+                }
                 goto out;
         }
 
-        lu->generation        = generation;
-        lu->tgt->node_id      = node_id;
-        lu->tgt->address_high = local_node_id << 16;
+        tgt->node_id      = node_id;
+        tgt->address_high = local_node_id << 16;
+        sbp2_set_generation(lu, generation);
 
         /* Get command block agent offset and login id. */
         lu->command_block_agent_address =
@@ -700,8 +861,8 @@ static void sbp2_login(struct work_struct *work)
                 response.command_block_agent.low;
         lu->login_id = LOGIN_RESPONSE_GET_LOGIN_ID(response);
 
-        fw_notify("logged in to %s LUN %04x (%d retries)\n",
-                  unit->device.bus_id, lu->lun, lu->retries);
+        fw_notify("%s: logged in to LUN %04x (%d retries)\n",
+                  tgt->bus_id, lu->lun, lu->retries);
 
 #if 0
         /* FIXME: The linux1394 sbp2 does this last step. */
@@ -711,26 +872,58 @@ static void sbp2_login(struct work_struct *work)
         PREPARE_DELAYED_WORK(&lu->work, sbp2_reconnect);
         sbp2_agent_reset(lu);
 
-        memset(&eight_bytes_lun, 0, sizeof(eight_bytes_lun));
-        eight_bytes_lun.scsi_lun[0] = (lu->lun >> 8) & 0xff;
-        eight_bytes_lun.scsi_lun[1] = lu->lun & 0xff;
+        /* This was a re-login. */
+        if (lu->has_sdev) {
+                sbp2_cancel_orbs(lu);
+                sbp2_conditionally_unblock(lu);
+                goto out;
+        }
 
-        sdev = __scsi_add_device(shost, 0, 0,
-                                 scsilun_to_int(&eight_bytes_lun), lu);
-        if (IS_ERR(sdev)) {
-                sbp2_send_management_orb(lu, node_id, generation,
-                                SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
-                /*
-                 * Set this back to sbp2_login so we fall back and
-                 * retry login on bus reset.
-                 */
-                PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
-        } else {
-                lu->sdev = sdev;
+        if (lu->tgt->workarounds & SBP2_WORKAROUND_DELAY_INQUIRY)
+                ssleep(SBP2_INQUIRY_DELAY);
+
+        shost = container_of((void *)tgt, struct Scsi_Host, hostdata[0]);
+        sdev = __scsi_add_device(shost, 0, 0, sbp2_lun2int(lu->lun), lu);
+        /*
+         * FIXME:  We are unable to perform reconnects while in sbp2_login().
+         * Therefore __scsi_add_device() will get into trouble if a bus reset
+         * happens in parallel.  It will either fail or leave us with an
+         * unusable sdev.  As a workaround we check for this and retry the
+         * whole login and SCSI probing.
+         */
+
+        /* Reported error during __scsi_add_device() */
+        if (IS_ERR(sdev))
+                goto out_logout_login;
+
+        /* Unreported error during __scsi_add_device() */
+        smp_rmb(); /* get current card generation */
+        if (generation != device->card->generation) {
+                scsi_remove_device(sdev);
                 scsi_device_put(sdev);
+                goto out_logout_login;
         }
+
+        /* No error during __scsi_add_device() */
+        lu->has_sdev = true;
+        scsi_device_put(sdev);
+        sbp2_allow_block(lu);
+        goto out;
+
+ out_logout_login:
+        smp_rmb(); /* generation may have changed */
+        generation = device->generation;
+        smp_rmb(); /* node_id must not be older than generation */
+
+        sbp2_send_management_orb(lu, device->node_id, generation,
+                                 SBP2_LOGOUT_REQUEST, lu->login_id, NULL);
+        /*
+         * If a bus reset happened, sbp2_update will have requeued
+         * lu->work already.  Reset the work from reconnect to login.
+         */
+        PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
  out:
-        sbp2_target_put(lu->tgt);
+        sbp2_target_put(tgt);
 }
 
 static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
@@ -751,10 +944,12 @@ static int sbp2_add_logical_unit(struct sbp2_target *tgt, int lun_entry)
                 return -ENOMEM;
         }
 
-        lu->tgt  = tgt;
-        lu->sdev = NULL;
-        lu->lun  = lun_entry & 0xffff;
-        lu->retries = 0;
+        lu->tgt      = tgt;
+        lu->lun      = lun_entry & 0xffff;
+        lu->retries  = 0;
+        lu->has_sdev = false;
+        lu->blocked  = false;
+        ++tgt->dont_block;
         INIT_LIST_HEAD(&lu->orb_list);
         INIT_DELAYED_WORK(&lu->work, sbp2_login);
 
@@ -813,7 +1008,7 @@ static int sbp2_scan_unit_dir(struct sbp2_target *tgt, u32 *directory,
                         if (timeout > tgt->mgt_orb_timeout)
                                 fw_notify("%s: config rom contains %ds "
                                           "management ORB timeout, limiting "
-                                          "to %ds\n", tgt->unit->device.bus_id,
+                                          "to %ds\n", tgt->bus_id,
                                           timeout / 1000,
                                           tgt->mgt_orb_timeout / 1000);
                         break;
@@ -836,12 +1031,12 @@ static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
                                   u32 firmware_revision)
 {
         int i;
-        unsigned w = sbp2_param_workarounds;
+        unsigned int w = sbp2_param_workarounds;
 
         if (w)
                 fw_notify("Please notify linux1394-devel@lists.sourceforge.net "
                           "if you need the workarounds parameter for %s\n",
-                          tgt->unit->device.bus_id);
+                          tgt->bus_id);
 
         if (w & SBP2_WORKAROUND_OVERRIDE)
                 goto out;
@@ -863,8 +1058,7 @@ static void sbp2_init_workarounds(struct sbp2_target *tgt, u32 model,
         if (w)
                 fw_notify("Workarounds for %s: 0x%x "
                           "(firmware_revision 0x%06x, model_id 0x%06x)\n",
-                          tgt->unit->device.bus_id,
-                          w, firmware_revision, model);
+                          tgt->bus_id, w, firmware_revision, model);
         tgt->workarounds = w;
 }
 
@@ -888,6 +1082,7 @@ static int sbp2_probe(struct device *dev)
         tgt->unit = unit;
         kref_init(&tgt->kref);
         INIT_LIST_HEAD(&tgt->lu_list);
+        tgt->bus_id = unit->device.bus_id;
 
         if (fw_device_enable_phys_dma(device) < 0)
                 goto fail_shost_put;
@@ -895,6 +1090,8 @@ static int sbp2_probe(struct device *dev)
         if (scsi_add_host(shost, &unit->device) < 0)
                 goto fail_shost_put;
 
+        fw_device_get(device);
+
         /* Initialize to values that won't match anything in our table. */
         firmware_revision = 0xff000000;
         model = 0xff000000;
@@ -938,10 +1135,13 @@ static void sbp2_reconnect(struct work_struct *work)
 {
         struct sbp2_logical_unit *lu =
                 container_of(work, struct sbp2_logical_unit, work.work);
-        struct fw_unit *unit = lu->tgt->unit;
-        struct fw_device *device = fw_device(unit->device.parent);
+        struct sbp2_target *tgt = lu->tgt;
+        struct fw_device *device = fw_device(tgt->unit->device.parent);
         int generation, node_id, local_node_id;
 
+        if (fw_device_is_shutdown(device))
+                goto out;
+
         generation    = device->generation;
         smp_rmb();    /* node_id must not be older than generation */
         node_id       = device->node_id;
@@ -950,10 +1150,17 @@ static void sbp2_reconnect(struct work_struct *work)
         if (sbp2_send_management_orb(lu, node_id, generation,
                                      SBP2_RECONNECT_REQUEST,
                                      lu->login_id, NULL) < 0) {
-                if (lu->retries++ >= 5) {
-                        fw_error("failed to reconnect to %s\n",
-                                 unit->device.bus_id);
-                        /* Fall back and try to log in again. */
+                /*
+                 * If reconnect was impossible even though we are in the
+                 * current generation, fall back and try to log in again.
+                 *
+                 * We could check for "Function rejected" status, but
+                 * looking at the bus generation as simpler and more general.
+                 */
+                smp_rmb(); /* get current card generation */
+                if (generation == device->card->generation ||
+                    lu->retries++ >= 5) {
+                        fw_error("%s: failed to reconnect\n", tgt->bus_id);
                         lu->retries = 0;
                         PREPARE_DELAYED_WORK(&lu->work, sbp2_login);
                 }
@@ -961,17 +1168,18 @@ static void sbp2_reconnect(struct work_struct *work)
                 goto out;
         }
 
-        lu->generation        = generation;
-        lu->tgt->node_id      = node_id;
-        lu->tgt->address_high = local_node_id << 16;
+        tgt->node_id      = node_id;
+        tgt->address_high = local_node_id << 16;
+        sbp2_set_generation(lu, generation);
 
-        fw_notify("reconnected to %s LUN %04x (%d retries)\n",
-                  unit->device.bus_id, lu->lun, lu->retries);
+        fw_notify("%s: reconnected to LUN %04x (%d retries)\n",
+                  tgt->bus_id, lu->lun, lu->retries);
 
         sbp2_agent_reset(lu);
         sbp2_cancel_orbs(lu);
+        sbp2_conditionally_unblock(lu);
  out:
-        sbp2_target_put(lu->tgt);
+        sbp2_target_put(tgt);
 }
 
 static void sbp2_update(struct fw_unit *unit)
@@ -986,6 +1194,7 @@ static void sbp2_update(struct fw_unit *unit)
          * Iteration over tgt->lu_list is therefore safe here.
          */
         list_for_each_entry(lu, &tgt->lu_list, link) {
+                sbp2_conditionally_block(lu);
                 lu->retries = 0;
                 sbp2_queue_work(lu, 0);
         }
@@ -1063,7 +1272,7 @@ complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
 
         if (status != NULL) {
                 if (STATUS_GET_DEAD(*status))
-                        sbp2_agent_reset(orb->lu);
+                        sbp2_agent_reset_no_wait(orb->lu);
 
                 switch (STATUS_GET_RESPONSE(*status)) {
                 case SBP2_STATUS_REQUEST_COMPLETE:
@@ -1089,6 +1298,7 @@ complete_command_orb(struct sbp2_orb *base_orb, struct sbp2_status *status)
                  * or when sending the write (less likely).
                  */
                 result = DID_BUS_BUSY << 16;
+                sbp2_conditionally_block(orb->lu);
         }
 
         dma_unmap_single(device->card->device, orb->base.request_bus,
@@ -1197,7 +1407,7 @@ static int sbp2_scsi_queuecommand(struct scsi_cmnd *cmd, scsi_done_fn_t done)
         struct sbp2_logical_unit *lu = cmd->device->hostdata;
         struct fw_device *device = fw_device(lu->tgt->unit->device.parent);
         struct sbp2_command_orb *orb;
-        unsigned max_payload;
+        unsigned int max_payload;
         int retval = SCSI_MLQUEUE_HOST_BUSY;
 
         /*
@@ -1275,6 +1485,10 @@ static int sbp2_scsi_slave_alloc(struct scsi_device *sdev)
 {
         struct sbp2_logical_unit *lu = sdev->hostdata;
 
+        /* (Re-)Adding logical units via the SCSI stack is not supported. */
+        if (!lu)
+                return -ENOSYS;
+
         sdev->allow_restart = 1;
 
         /*
@@ -1319,7 +1533,7 @@ static int sbp2_scsi_abort(struct scsi_cmnd *cmd)
 {
         struct sbp2_logical_unit *lu = cmd->device->hostdata;
 
-        fw_notify("sbp2_scsi_abort\n");
+        fw_notify("%s: sbp2_scsi_abort\n", lu->tgt->bus_id);
         sbp2_agent_reset(lu);
         sbp2_cancel_orbs(lu);