[SCSI] scsi_error: add target reset handler
Mike Christie [Sat, 1 Mar 2008 00:25:19 +0000 (18:25 -0600)]
The problem is that serveral drivers are sending a target reset from the
device reset handler, and if we have multiple devices a target reset gets
sent for each device when only one would be sufficient. And if we do a target
reset it affects all the commands on the target so the device reset handler
code only cleaning up one devices's commands makes programming the driver a
little more difficult than it should be.

This patch adds a target reset handler, which drivers can use to send
a target reset. If successful it cleans up the commands for a devices
accessed through that starget.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/scsi_error.c
include/scsi/scsi_eh.h
include/scsi/scsi_host.h

index 045a086..1221d2c 100644 (file)
@@ -524,6 +524,41 @@ static int scsi_try_bus_reset(struct scsi_cmnd *scmd)
        return rtn;
 }
 
+static void __scsi_report_device_reset(struct scsi_device *sdev, void *data)
+{
+       sdev->was_reset = 1;
+       sdev->expecting_cc_ua = 1;
+}
+
+/**
+ * scsi_try_target_reset - Ask host to perform a target reset
+ * @scmd:      SCSI cmd used to send a target reset
+ *
+ * Notes:
+ *    There is no timeout for this operation.  if this operation is
+ *    unreliable for a given host, then the host itself needs to put a
+ *    timer on it, and set the host back to a consistent state prior to
+ *    returning.
+ */
+static int scsi_try_target_reset(struct scsi_cmnd *scmd)
+{
+       unsigned long flags;
+       int rtn;
+
+       if (!scmd->device->host->hostt->eh_target_reset_handler)
+               return FAILED;
+
+       rtn = scmd->device->host->hostt->eh_target_reset_handler(scmd);
+       if (rtn == SUCCESS) {
+               spin_lock_irqsave(scmd->device->host->host_lock, flags);
+               __starget_for_each_device(scsi_target(scmd->device), NULL,
+                                         __scsi_report_device_reset);
+               spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
+       }
+
+       return rtn;
+}
+
 /**
  * scsi_try_bus_device_reset - Ask host to perform a BDR on a dev
  * @scmd:      SCSI cmd used to send BDR
@@ -542,11 +577,8 @@ static int scsi_try_bus_device_reset(struct scsi_cmnd *scmd)
                return FAILED;
 
        rtn = scmd->device->host->hostt->eh_device_reset_handler(scmd);
-       if (rtn == SUCCESS) {
-               scmd->device->was_reset = 1;
-               scmd->device->expecting_cc_ua = 1;
-       }
-
+       if (rtn == SUCCESS)
+               __scsi_report_device_reset(scmd->device, NULL);
        return rtn;
 }
 
@@ -584,8 +616,9 @@ static void scsi_abort_eh_cmnd(struct scsi_cmnd *scmd)
 {
        if (__scsi_try_to_abort_cmd(scmd) != SUCCESS)
                if (scsi_try_bus_device_reset(scmd) != SUCCESS)
-                       if (scsi_try_bus_reset(scmd) != SUCCESS)
-                               scsi_try_host_reset(scmd);
+                       if (scsi_try_target_reset(scmd) != SUCCESS)
+                               if (scsi_try_bus_reset(scmd) != SUCCESS)
+                                       scsi_try_host_reset(scmd);
 }
 
 /**
@@ -1060,6 +1093,56 @@ static int scsi_eh_bus_device_reset(struct Scsi_Host *shost,
 }
 
 /**
+ * scsi_eh_target_reset - send target reset if needed
+ * @shost:     scsi host being recovered.
+ * @work_q:     &list_head for pending commands.
+ * @done_q:    &list_head for processed commands.
+ *
+ * Notes:
+ *    Try a target reset.
+ */
+static int scsi_eh_target_reset(struct Scsi_Host *shost,
+                               struct list_head *work_q,
+                               struct list_head *done_q)
+{
+       struct scsi_cmnd *scmd, *tgtr_scmd, *next;
+       unsigned int id;
+       int rtn;
+
+       for (id = 0; id <= shost->max_id; id++) {
+               tgtr_scmd = NULL;
+               list_for_each_entry(scmd, work_q, eh_entry) {
+                       if (id == scmd_id(scmd)) {
+                               tgtr_scmd = scmd;
+                               break;
+                       }
+               }
+               if (!tgtr_scmd)
+                       continue;
+
+               SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Sending target reset "
+                                                 "to target %d\n",
+                                                 current->comm, id));
+               rtn = scsi_try_target_reset(tgtr_scmd);
+               if (rtn == SUCCESS) {
+                       list_for_each_entry_safe(scmd, next, work_q, eh_entry) {
+                               if (id == scmd_id(scmd))
+                                       if (!scsi_device_online(scmd->device) ||
+                                           !scsi_eh_tur(tgtr_scmd))
+                                               scsi_eh_finish_cmd(scmd,
+                                                                  done_q);
+                       }
+               } else
+                       SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Target reset"
+                                                         " failed target: "
+                                                         "%d\n",
+                                                         current->comm, id));
+       }
+
+       return list_empty(work_q);
+}
+
+/**
  * scsi_eh_bus_reset - send a bus reset 
  * @shost:     &scsi host being recovered.
  * @work_q:     &list_head for pending commands.
@@ -1447,9 +1530,11 @@ void scsi_eh_ready_devs(struct Scsi_Host *shost,
 {
        if (!scsi_eh_stu(shost, work_q, done_q))
                if (!scsi_eh_bus_device_reset(shost, work_q, done_q))
-                       if (!scsi_eh_bus_reset(shost, work_q, done_q))
-                               if (!scsi_eh_host_reset(work_q, done_q))
-                                       scsi_eh_offline_sdevs(work_q, done_q);
+                       if (!scsi_eh_target_reset(shost, work_q, done_q))
+                               if (!scsi_eh_bus_reset(shost, work_q, done_q))
+                                       if (!scsi_eh_host_reset(work_q, done_q))
+                                               scsi_eh_offline_sdevs(work_q,
+                                                                     done_q);
 }
 EXPORT_SYMBOL_GPL(scsi_eh_ready_devs);
 
@@ -1619,10 +1704,8 @@ void scsi_report_bus_reset(struct Scsi_Host *shost, int channel)
        struct scsi_device *sdev;
 
        __shost_for_each_device(sdev, shost) {
-               if (channel == sdev_channel(sdev)) {
-                       sdev->was_reset = 1;
-                       sdev->expecting_cc_ua = 1;
-               }
+               if (channel == sdev_channel(sdev))
+                       __scsi_report_device_reset(sdev, NULL);
        }
 }
 EXPORT_SYMBOL(scsi_report_bus_reset);
@@ -1655,10 +1738,8 @@ void scsi_report_device_reset(struct Scsi_Host *shost, int channel, int target)
 
        __shost_for_each_device(sdev, shost) {
                if (channel == sdev_channel(sdev) &&
-                   target == sdev_id(sdev)) {
-                       sdev->was_reset = 1;
-                       sdev->expecting_cc_ua = 1;
-               }
+                   target == sdev_id(sdev))
+                       __scsi_report_device_reset(sdev, NULL);
        }
 }
 EXPORT_SYMBOL(scsi_report_device_reset);
@@ -1714,6 +1795,11 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
                if (rtn == SUCCESS)
                        break;
                /* FALLTHROUGH */
+       case SCSI_TRY_RESET_TARGET:
+               rtn = scsi_try_target_reset(scmd);
+               if (rtn == SUCCESS)
+                       break;
+               /* FALLTHROUGH */
        case SCSI_TRY_RESET_BUS:
                rtn = scsi_try_bus_reset(scmd);
                if (rtn == SUCCESS)
index 25071d5..37a7614 100644 (file)
@@ -64,6 +64,7 @@ extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
 #define SCSI_TRY_RESET_DEVICE  1
 #define SCSI_TRY_RESET_BUS     2
 #define SCSI_TRY_RESET_HOST    3
+#define SCSI_TRY_RESET_TARGET  4
 
 extern int scsi_reset_provider(struct scsi_device *, int);
 
index 530ff4c..4913286 100644 (file)
@@ -172,6 +172,7 @@ struct scsi_host_template {
         */
        int (* eh_abort_handler)(struct scsi_cmnd *);
        int (* eh_device_reset_handler)(struct scsi_cmnd *);
+       int (* eh_target_reset_handler)(struct scsi_cmnd *);
        int (* eh_bus_reset_handler)(struct scsi_cmnd *);
        int (* eh_host_reset_handler)(struct scsi_cmnd *);