2 files changed, 69 insertions, 5 deletions

diff --git a/drivers/ieee1394/sbp2.c b/drivers/ieee1394/sbp2.c
index 668b4512def..c4d30a7b8b1 100644
--- a/drivers/ieee1394/sbp2.c
+++ b/drivers/ieee1394/sbp2.c
@@ -465,6 +465,44 @@ static int sbp2util_node_write_no_wait(struct node_entry *ne, u64 addr,
         return 0;
 }
 
+static void sbp2util_notify_fetch_agent(struct scsi_id_instance_data *scsi_id,
+                                        u64 offset, quadlet_t *data, size_t len)
+{
+        /*
+         * There is a small window after a bus reset within which the node
+         * entry's generation is current but the reconnect wasn't completed.
+         */
+        if (atomic_read(&scsi_id->unfinished_reset))
+                return;
+
+        if (hpsb_node_write(scsi_id->ne,
+                            scsi_id->sbp2_command_block_agent_addr + offset,
+                            data, len))
+                SBP2_ERR("sbp2util_notify_fetch_agent failed.");
+        /*
+         * Now accept new SCSI commands, unless a bus reset happended during
+         * hpsb_node_write.
+         */
+        if (!atomic_read(&scsi_id->unfinished_reset))
+                scsi_unblock_requests(scsi_id->scsi_host);
+}
+
+static void sbp2util_write_orb_pointer(void *p)
+{
+        quadlet_t data[2];
+
+        data[0] = ORB_SET_NODE_ID(
+                        ((struct scsi_id_instance_data *)p)->hi->host->node_id);
+        data[1] = ((struct scsi_id_instance_data *)p)->last_orb_dma;
+        sbp2util_cpu_to_be32_buffer(data, 8);
+        sbp2util_notify_fetch_agent(p, SBP2_ORB_POINTER_OFFSET, data, 8);
+}
+
+static void sbp2util_write_doorbell(void *p)
+{
+        sbp2util_notify_fetch_agent(p, SBP2_DOORBELL_OFFSET, NULL, 4);
+}
+
 /*
  * This function is called to create a pool of command orbs used for
  * command processing. It is called when a new sbp2 device is detected.
@@ -712,6 +750,7 @@ static int sbp2_remove(struct device *dev)
                         sbp2scsi_complete_all_commands(scsi_id, DID_NO_CONNECT);
                 /* scsi_remove_device() will trigger shutdown functions of SCSI
                  * highlevel drivers which would deadlock if blocked. */
+                atomic_set(&scsi_id->unfinished_reset, 0);
                 scsi_unblock_requests(scsi_id->scsi_host);
         }
         sdev = scsi_id->sdev;
@@ -765,6 +804,7 @@ static int sbp2_update(struct unit_directory *ud)
 
         /* Make sure we unblock requests (since this is likely after a bus
          * reset). */
+        atomic_set(&scsi_id->unfinished_reset, 0);
         scsi_unblock_requests(scsi_id->scsi_host);
 
         return 0;
@@ -795,6 +835,8 @@ static struct scsi_id_instance_data *sbp2_alloc_device(struct unit_directory *ud
         INIT_LIST_HEAD(&scsi_id->sbp2_command_orb_completed);
         INIT_LIST_HEAD(&scsi_id->scsi_list);
         spin_lock_init(&scsi_id->sbp2_command_orb_lock);
+        atomic_set(&scsi_id->unfinished_reset, 0);
+        INIT_WORK(&scsi_id->protocol_work, NULL, NULL);
 
         ud->device.driver_data = scsi_id;
 
@@ -879,8 +921,10 @@ static void sbp2_host_reset(struct hpsb_host *host)
         hi = hpsb_get_hostinfo(&sbp2_highlevel, host);
 
         if (hi) {
-                list_for_each_entry(scsi_id, &hi->scsi_ids, scsi_list)
+                list_for_each_entry(scsi_id, &hi->scsi_ids, scsi_list) {
+                        atomic_set(&scsi_id->unfinished_reset, 1);
                         scsi_block_requests(scsi_id->scsi_host);
+                }
         }
 }
 
@@ -1032,7 +1076,7 @@ static void sbp2_remove_device(struct scsi_id_instance_data *scsi_id)
                 scsi_remove_host(scsi_id->scsi_host);
                 scsi_host_put(scsi_id->scsi_host);
         }
-
+        flush_scheduled_work();
         sbp2util_remove_command_orb_pool(scsi_id);
 
         list_del(&scsi_id->scsi_list);
@@ -1661,6 +1705,10 @@ static int sbp2_agent_reset(struct scsi_id_instance_data *scsi_id, int wait)
 
         SBP2_DEBUG_ENTER();
 
+        cancel_delayed_work(&scsi_id->protocol_work);
+        if (wait)
+                flush_scheduled_work();
+
         data = ntohl(SBP2_AGENT_RESET_DATA);
         addr = scsi_id->sbp2_command_block_agent_addr + SBP2_AGENT_RESET_OFFSET;
 
@@ -1982,9 +2030,22 @@ static void sbp2_link_orb_command(struct scsi_id_instance_data *scsi_id,
 
         SBP2_ORB_DEBUG("write to %s register, command orb %p",
                         last_orb ? "DOORBELL" : "ORB_POINTER", command_orb);
-        if (sbp2util_node_write_no_wait(scsi_id->ne, addr, data, length))
-                SBP2_ERR("sbp2util_node_write_no_wait failed.\n");
-        /* We rely on SCSI EH to deal with _node_write_ failures. */
+        if (sbp2util_node_write_no_wait(scsi_id->ne, addr, data, length)) {
+                /*
+                 * sbp2util_node_write_no_wait failed. We certainly ran out
+                 * of transaction labels, perhaps just because there were no
+                 * context switches which gave khpsbpkt a chance to collect
+                 * free tlabels. Try again in non-atomic context. If necessary,
+                 * the workqueue job will sleep to guaranteedly get a tlabel.
+                 * We do not accept new commands until the job is over.
+                 */
+                scsi_block_requests(scsi_id->scsi_host);
+                PREPARE_WORK(&scsi_id->protocol_work,
+                             last_orb ? sbp2util_write_doorbell:
+                                        sbp2util_write_orb_pointer,
+                             scsi_id);
+                schedule_work(&scsi_id->protocol_work);
+        }
 }
 
 /*
diff --git a/drivers/ieee1394/sbp2.h b/drivers/ieee1394/sbp2.h
index 89098fe565e..1c9fe422cf4 100644
--- a/drivers/ieee1394/sbp2.h
+++ b/drivers/ieee1394/sbp2.h
@@ -346,6 +346,9 @@ struct scsi_id_instance_data {
 
         /* Device specific workarounds/brokeness */
         unsigned workarounds;
+
+        atomic_t unfinished_reset;
+        struct work_struct protocol_work;
 };
 
 /* Sbp2 host data structure (one per IEEE1394 host) */