[SCSI] ibmvscsi: Add eh_host_reset_handler

Adds an eh_host_reset_handler to ibmvscsi which resets the connection
to the vscsi server. This patch also adds a timer to internally
issues commands to prevent client hangs in the case of a misbehaving
server. Tested by modifying the VIOS such that it would occasionally
drop one or more request in sequence.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 107 insertions, 30 deletions

diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
index c63a26e2fbc7..0a16972b2599 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.c
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
@@ -509,6 +509,70 @@ static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
         return map_single_data(cmd, srp_cmd, dev);
 }
 
+/**
+ * purge_requests: Our virtual adapter just shut down.  purge any sent requests
+ * @hostdata:    the adapter
+ */
+static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
+{
+        struct srp_event_struct *tmp_evt, *pos;
+        unsigned long flags;
+
+        spin_lock_irqsave(hostdata->host->host_lock, flags);
+        list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
+                list_del(&tmp_evt->list);
+                del_timer(&tmp_evt->timer);
+                if (tmp_evt->cmnd) {
+                        tmp_evt->cmnd->result = (error_code << 16);
+                        unmap_cmd_data(&tmp_evt->iu.srp.cmd,
+                                       tmp_evt,
+                                       tmp_evt->hostdata->dev);
+                        if (tmp_evt->cmnd_done)
+                                tmp_evt->cmnd_done(tmp_evt->cmnd);
+                } else if (tmp_evt->done)
+                        tmp_evt->done(tmp_evt);
+                free_event_struct(&tmp_evt->hostdata->pool, tmp_evt);
+        }
+        spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+}
+
+/**
+ * ibmvscsi_reset_host - Reset the connection to the server
+ * @hostdata:   struct ibmvscsi_host_data to reset
+*/
+static void ibmvscsi_reset_host(struct ibmvscsi_host_data *hostdata)
+{
+        scsi_block_requests(hostdata->host);
+        atomic_set(&hostdata->request_limit, 0);
+
+        purge_requests(hostdata, DID_ERROR);
+        if ((ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata)) ||
+            (ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0)) ||
+            (vio_enable_interrupts(to_vio_dev(hostdata->dev)))) {
+                atomic_set(&hostdata->request_limit, -1);
+                dev_err(hostdata->dev, "error after reset\n");
+        }
+
+        scsi_unblock_requests(hostdata->host);
+}
+
+/**
+ * ibmvscsi_timeout - Internal command timeout handler
+ * @evt_struct: struct srp_event_struct that timed out
+ *
+ * Called when an internally generated command times out
+*/
+static void ibmvscsi_timeout(struct srp_event_struct *evt_struct)
+{
+        struct ibmvscsi_host_data *hostdata = evt_struct->hostdata;
+
+        dev_err(hostdata->dev, "Command timed out (%x). Resetting connection\n",
+                evt_struct->iu.srp.cmd.opcode);
+
+        ibmvscsi_reset_host(hostdata);
+}
+
+
 /* ------------------------------------------------------------
  * Routines for sending and receiving SRPs
  */
@@ -516,12 +580,14 @@ static int map_data_for_srp_cmd(struct scsi_cmnd *cmd,
  * ibmvscsi_send_srp_event: - Transforms event to u64 array and calls send_crq()
  * @evt_struct: evt_struct to be sent
  * @hostdata:   ibmvscsi_host_data of host
+ * @timeout:    timeout in seconds - 0 means do not time command
  *
  * Returns the value returned from ibmvscsi_send_crq(). (Zero for success)
  * Note that this routine assumes that host_lock is held for synchronization
 */
 static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
-                                   struct ibmvscsi_host_data *hostdata)
+                                   struct ibmvscsi_host_data *hostdata,
+                                   unsigned long timeout)
 {
         u64 *crq_as_u64 = (u64 *) &evt_struct->crq;
         int request_status;
@@ -577,9 +643,18 @@ static int ibmvscsi_send_srp_event(struct srp_event_struct *evt_struct,
          */
         list_add_tail(&evt_struct->list, &hostdata->sent);
 
+        init_timer(&evt_struct->timer);
+        if (timeout) {
+                evt_struct->timer.data = (unsigned long) evt_struct;
+                evt_struct->timer.expires = jiffies + (timeout * HZ);
+                evt_struct->timer.function = (void (*)(unsigned long))ibmvscsi_timeout;
+                add_timer(&evt_struct->timer);
+        }
+
         if ((rc =
              ibmvscsi_send_crq(hostdata, crq_as_u64[0], crq_as_u64[1])) != 0) {
                 list_del(&evt_struct->list);
+                del_timer(&evt_struct->timer);
 
                 dev_err(hostdata->dev, "send error %d\n", rc);
                 atomic_inc(&hostdata->request_limit);
@@ -709,7 +784,7 @@ static int ibmvscsi_queuecommand(struct scsi_cmnd *cmnd,
                         offsetof(struct srp_indirect_buf, desc_list);
         }
 
-        return ibmvscsi_send_srp_event(evt_struct, hostdata);
+        return ibmvscsi_send_srp_event(evt_struct, hostdata, 0);
 }
 
 /* ------------------------------------------------------------
@@ -800,7 +875,7 @@ static void send_mad_adapter_info(struct ibmvscsi_host_data *hostdata)
                 return;
         }
         
-        if (ibmvscsi_send_srp_event(evt_struct, hostdata)) {
+        if (ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2)) {
                 dev_err(hostdata->dev, "couldn't send ADAPTER_INFO_REQ!\n");
                 dma_unmap_single(hostdata->dev,
                                  addr,
@@ -889,7 +964,7 @@ static int send_srp_login(struct ibmvscsi_host_data *hostdata)
          */
         atomic_set(&hostdata->request_limit, 1);
 
-        rc = ibmvscsi_send_srp_event(evt_struct, hostdata);
+        rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         dev_info(hostdata->dev, "sent SRP login\n");
         return rc;
@@ -969,7 +1044,7 @@ static int ibmvscsi_eh_abort_handler(struct scsi_cmnd *cmd)
 
         evt->sync_srp = &srp_rsp;
         init_completion(&evt->comp);
-        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata);
+        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         if (rsp_rc != 0) {
                 sdev_printk(KERN_ERR, cmd->device,
@@ -1077,7 +1152,7 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
 
         evt->sync_srp = &srp_rsp;
         init_completion(&evt->comp);
-        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata);
+        rsp_rc = ibmvscsi_send_srp_event(evt, hostdata, init_timeout * 2);
         spin_unlock_irqrestore(hostdata->host->host_lock, flags);
         if (rsp_rc != 0) {
                 sdev_printk(KERN_ERR, cmd->device,
@@ -1133,32 +1208,30 @@ static int ibmvscsi_eh_device_reset_handler(struct scsi_cmnd *cmd)
 }
 
 /**
- * purge_requests: Our virtual adapter just shut down.  purge any sent requests
- * @hostdata:    the adapter
- */
-static void purge_requests(struct ibmvscsi_host_data *hostdata, int error_code)
+ * ibmvscsi_eh_host_reset_handler - Reset the connection to the server
+ * @cmd:        struct scsi_cmnd having problems
+*/
+static int ibmvscsi_eh_host_reset_handler(struct scsi_cmnd *cmd)
 {
-        struct srp_event_struct *tmp_evt, *pos;
-        unsigned long flags;
+        unsigned long wait_switch = 0;
+        struct ibmvscsi_host_data *hostdata =
+                (struct ibmvscsi_host_data *)cmd->device->host->hostdata;
 
-        spin_lock_irqsave(hostdata->host->host_lock, flags);
-        list_for_each_entry_safe(tmp_evt, pos, &hostdata->sent, list) {
-                list_del(&tmp_evt->list);
-                if (tmp_evt->cmnd) {
-                        tmp_evt->cmnd->result = (error_code << 16);
-                        unmap_cmd_data(&tmp_evt->iu.srp.cmd, 
-                                       tmp_evt, 
-                                       tmp_evt->hostdata->dev);
-                        if (tmp_evt->cmnd_done)
-                                tmp_evt->cmnd_done(tmp_evt->cmnd);
-                } else {
-                        if (tmp_evt->done) {
-                                tmp_evt->done(tmp_evt);
-                        }
-                }
-                free_event_struct(&tmp_evt->hostdata->pool, tmp_evt);
+        dev_err(hostdata->dev, "Resetting connection due to error recovery\n");
+
+        ibmvscsi_reset_host(hostdata);
+
+        for (wait_switch = jiffies + (init_timeout * HZ);
+             time_before(jiffies, wait_switch) &&
+                     atomic_read(&hostdata->request_limit) < 2;) {
+
+                msleep(10);
         }
-        spin_unlock_irqrestore(hostdata->host->host_lock, flags);
+
+        if (atomic_read(&hostdata->request_limit) <= 0)
+                return FAILED;
+
+        return SUCCESS;
 }
 
 /**
@@ -1258,6 +1331,8 @@ void ibmvscsi_handle_crq(struct viosrp_crq *crq,
                 atomic_add(evt_struct->xfer_iu->srp.rsp.req_lim_delta,
                            &hostdata->request_limit);
 
+        del_timer(&evt_struct->timer);
+
         if (evt_struct->done)
                 evt_struct->done(evt_struct);
         else
@@ -1313,7 +1388,7 @@ static int ibmvscsi_do_host_config(struct ibmvscsi_host_data *hostdata,
         }
 
         init_completion(&evt_struct->comp);
-        rc = ibmvscsi_send_srp_event(evt_struct, hostdata);
+        rc = ibmvscsi_send_srp_event(evt_struct, hostdata, init_timeout * 2);
         if (rc == 0)
                 wait_for_completion(&evt_struct->comp);
         dma_unmap_single(hostdata->dev, addr, length, DMA_BIDIRECTIONAL);
@@ -1504,6 +1579,7 @@ static struct scsi_host_template driver_template = {
         .queuecommand = ibmvscsi_queuecommand,
         .eh_abort_handler = ibmvscsi_eh_abort_handler,
         .eh_device_reset_handler = ibmvscsi_eh_device_reset_handler,
+        .eh_host_reset_handler = ibmvscsi_eh_host_reset_handler,
         .slave_configure = ibmvscsi_slave_configure,
         .change_queue_depth = ibmvscsi_change_queue_depth,
         .cmd_per_lun = 16,
diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.h b/drivers/scsi/ibmvscsi/ibmvscsi.h
index 727ca7c95926..b19c2e26c2a5 100644
--- a/drivers/scsi/ibmvscsi/ibmvscsi.h
+++ b/drivers/scsi/ibmvscsi/ibmvscsi.h
@@ -70,6 +70,7 @@ struct srp_event_struct {
         union viosrp_iu iu;
         void (*cmnd_done) (struct scsi_cmnd *);
         struct completion comp;
+        struct timer_list timer;
         union viosrp_iu *sync_srp;
         struct srp_direct_buf *ext_list;
         dma_addr_t ext_list_token;