[SCSI] Generate uevents on certain unit attention codes

Generate a uevent when the following Unit Attention ASC/ASCQ
codes are received:

    2A/01  MODE PARAMETERS CHANGED
    2A/09  CAPACITY DATA HAS CHANGED
    38/07  THIN PROVISIONING SOFT THRESHOLD REACHED
    3F/03  INQUIRY DATA HAS CHANGED
    3F/0E  REPORTED LUNS DATA HAS CHANGED

Log kernel messages when the following Unit Attention ASC/ASCQ
codes are received that are not as specific as those above:

    2A/xx  PARAMETERS CHANGED
    3F/xx  TARGET OPERATING CONDITIONS HAVE CHANGED

Added logic to set expecting_lun_change for other LUNs on the target
after REPORTED LUNS DATA HAS CHANGED is received, so that duplicate
uevents are not generated, and clear expecting_lun_change when a
REPORT LUNS command completes, in accordance with the SPC-3
specification regarding reporting of the 3F 0E ASC/ASCQ UA.

[jejb: remove SPC3 test in scsi_report_lun_change and some docbook fixes and
       unused variable fix, both reported by Fengguang Wu]
Signed-off-by: Ewan D. Milne <emilne@redhat.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

4 files changed, 127 insertions, 22 deletions

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index a46c3dddcf70..83e591b60193 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -223,6 +223,74 @@ static inline void scsi_eh_prt_fail_stats(struct Scsi_Host *shost,
 }
 #endif
 
+ /**
+ * scsi_report_lun_change - Set flag on all *other* devices on the same target
+ *                          to indicate that a UNIT ATTENTION is expected.
+ * @sdev:       Device reporting the UNIT ATTENTION
+ */
+static void scsi_report_lun_change(struct scsi_device *sdev)
+{
+        sdev->sdev_target->expecting_lun_change = 1;
+}
+
+/**
+ * scsi_report_sense - Examine scsi sense information and log messages for
+ *                     certain conditions, also issue uevents for some of them.
+ * @sdev:       Device reporting the sense code
+ * @sshdr:      sshdr to be examined
+ */
+static void scsi_report_sense(struct scsi_device *sdev,
+                              struct scsi_sense_hdr *sshdr)
+{
+        enum scsi_device_event evt_type = SDEV_EVT_MAXBITS;     /* i.e. none */
+
+        if (sshdr->sense_key == UNIT_ATTENTION) {
+                if (sshdr->asc == 0x3f && sshdr->ascq == 0x03) {
+                        evt_type = SDEV_EVT_INQUIRY_CHANGE_REPORTED;
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Inquiry data has changed");
+                } else if (sshdr->asc == 0x3f && sshdr->ascq == 0x0e) {
+                        evt_type = SDEV_EVT_LUN_CHANGE_REPORTED;
+                        scsi_report_lun_change(sdev);
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Warning! Received an indication that the "
+                                    "LUN assignments on this target have "
+                                    "changed. The Linux SCSI layer does not "
+                                    "automatically remap LUN assignments.\n");
+                } else if (sshdr->asc == 0x3f)
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Warning! Received an indication that the "
+                                    "operating parameters on this target have "
+                                    "changed. The Linux SCSI layer does not "
+                                    "automatically adjust these parameters.\n");
+
+                if (sshdr->asc == 0x38 && sshdr->ascq == 0x07) {
+                        evt_type = SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED;
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Warning! Received an indication that the "
+                                    "LUN reached a thin provisioning soft "
+                                    "threshold.\n");
+                }
+
+                if (sshdr->asc == 0x2a && sshdr->ascq == 0x01) {
+                        evt_type = SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED;
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Mode parameters changed");
+                } else if (sshdr->asc == 0x2a && sshdr->ascq == 0x09) {
+                        evt_type = SDEV_EVT_CAPACITY_CHANGE_REPORTED;
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Capacity data has changed");
+                } else if (sshdr->asc == 0x2a)
+                        sdev_printk(KERN_WARNING, sdev,
+                                    "Parameters changed");
+        }
+
+        if (evt_type != SDEV_EVT_MAXBITS) {
+                set_bit(evt_type, sdev->pending_events);
+                schedule_work(&sdev->event_work);
+        }
+}
+
 /**
  * scsi_check_sense - Examine scsi cmd sense
  * @scmd:       Cmd to have sense checked.
@@ -250,6 +318,8 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
                  */
                 return SUCCESS;
 
+        scsi_report_sense(sdev, &sshdr);
+
         if (scsi_sense_is_deferred(&sshdr))
                 return NEEDS_RETRY;
 
@@ -315,6 +385,14 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
                         }
                 }
                 /*
+                 * we might also expect a cc/ua if another LUN on the target
+                 * reported a UA with an ASC/ASCQ of 3F 0E -
+                 * REPORTED LUNS DATA HAS CHANGED.
+                 */
+                if (scmd->device->sdev_target->expecting_lun_change &&
+                    sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
+                        return NEEDS_RETRY;
+                /*
                  * if the device is in the process of becoming ready, we
                  * should retry.
                  */
@@ -327,26 +405,6 @@ static int scsi_check_sense(struct scsi_cmnd *scmd)
                 if (scmd->device->allow_restart &&
                     (sshdr.asc == 0x04) && (sshdr.ascq == 0x02))
                         return FAILED;
-
-                if (sshdr.asc == 0x3f && sshdr.ascq == 0x0e)
-                        scmd_printk(KERN_WARNING, scmd,
-                                    "Warning! Received an indication that the "
-                                    "LUN assignments on this target have "
-                                    "changed. The Linux SCSI layer does not "
-                                    "automatically remap LUN assignments.\n");
-                else if (sshdr.asc == 0x3f)
-                        scmd_printk(KERN_WARNING, scmd,
-                                    "Warning! Received an indication that the "
-                                    "operating parameters on this target have "
-                                    "changed. The Linux SCSI layer does not "
-                                    "automatically adjust these parameters.\n");
-
-                if (sshdr.asc == 0x38 && sshdr.ascq == 0x07)
-                        scmd_printk(KERN_WARNING, scmd,
-                                    "Warning! Received an indication that the "
-                                    "LUN reached a thin provisioning soft "
-                                    "threshold.\n");
-
                 /*
                  * Pass the UA upwards for a determination in the completion
                  * functions.
@@ -1574,6 +1632,8 @@ int scsi_decide_disposition(struct scsi_cmnd *scmd)
                  */
                 return ADD_TO_MLQUEUE;
         case GOOD:
+                if (scmd->cmnd[0] == REPORT_LUNS)
+                        scmd->device->sdev_target->expecting_lun_change = 0;
                 scsi_handle_queue_ramp_up(scmd->device);
         case COMMAND_TERMINATED:
                 return SUCCESS;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 36b5c898db9d..d545931c85eb 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2253,7 +2253,21 @@ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
         case SDEV_EVT_MEDIA_CHANGE:
                 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
                 break;
-
+        case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
+                envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
+                break;
+        case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
+                envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
+                break;
+        case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
+               envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
+                break;
+        case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
+                envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
+                break;
+        case SDEV_EVT_LUN_CHANGE_REPORTED:
+                envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
+                break;
         default:
                 /* do nothing */
                 break;
@@ -2274,10 +2288,15 @@ static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
 void scsi_evt_thread(struct work_struct *work)
 {
         struct scsi_device *sdev;
+        enum scsi_device_event evt_type;
         LIST_HEAD(event_list);
 
         sdev = container_of(work, struct scsi_device, event_work);
 
+        for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
+                if (test_and_clear_bit(evt_type, sdev->pending_events))
+                        sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
+
         while (1) {
                 struct scsi_event *evt;
                 struct list_head *this, *tmp;
@@ -2347,6 +2366,11 @@ struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
         /* evt_type-specific initialization, if any */
         switch (evt_type) {
         case SDEV_EVT_MEDIA_CHANGE:
+        case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
+        case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
+        case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
+        case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
+        case SDEV_EVT_LUN_CHANGE_REPORTED:
         default:
                 /* do nothing */
                 break;
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 7e50061e9ef6..40c639491b27 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -739,6 +739,11 @@ sdev_store_evt_##name(struct device *dev, struct device_attribute *attr,\
 #define REF_EVT(name) &dev_attr_evt_##name.attr
 
 DECLARE_EVT(media_change, MEDIA_CHANGE)
+DECLARE_EVT(inquiry_change_reported, INQUIRY_CHANGE_REPORTED)
+DECLARE_EVT(capacity_change_reported, CAPACITY_CHANGE_REPORTED)
+DECLARE_EVT(soft_threshold_reached, SOFT_THRESHOLD_REACHED_REPORTED)
+DECLARE_EVT(mode_parameter_change_reported, MODE_PARAMETER_CHANGE_REPORTED)
+DECLARE_EVT(lun_change_reported, LUN_CHANGE_REPORTED)
 
 /* Default template for device attributes.  May NOT be modified */
 static struct attribute *scsi_sdev_attrs[] = {
@@ -759,6 +764,11 @@ static struct attribute *scsi_sdev_attrs[] = {
         &dev_attr_ioerr_cnt.attr,
         &dev_attr_modalias.attr,
         REF_EVT(media_change),
+        REF_EVT(inquiry_change_reported),
+        REF_EVT(capacity_change_reported),
+        REF_EVT(soft_threshold_reached),
+        REF_EVT(mode_parameter_change_reported),
+        REF_EVT(lun_change_reported),
         NULL
 };
 
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index a44954c7cdc2..d65fbec2533d 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -52,8 +52,15 @@ enum scsi_device_state {
 
 enum scsi_device_event {
         SDEV_EVT_MEDIA_CHANGE   = 1,    /* media has changed */
+        SDEV_EVT_INQUIRY_CHANGE_REPORTED,               /* 3F 03  UA reported */
+        SDEV_EVT_CAPACITY_CHANGE_REPORTED,              /* 2A 09  UA reported */
+        SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED,       /* 38 07  UA reported */
+        SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED,        /* 2A 01  UA reported */
+        SDEV_EVT_LUN_CHANGE_REPORTED,                   /* 3F 0E  UA reported */
+
+        SDEV_EVT_FIRST          = SDEV_EVT_MEDIA_CHANGE,
+        SDEV_EVT_LAST           = SDEV_EVT_LUN_CHANGE_REPORTED,
 
-        SDEV_EVT_LAST           = SDEV_EVT_MEDIA_CHANGE,
         SDEV_EVT_MAXBITS        = SDEV_EVT_LAST + 1
 };
 
@@ -164,6 +171,7 @@ struct scsi_device {
         atomic_t disk_events_disable_depth; /* disable depth for disk events */
 
         DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
+        DECLARE_BITMAP(pending_events, SDEV_EVT_MAXBITS); /* pending events */
         struct list_head event_list;    /* asserted events */
         struct work_struct event_work;
 
@@ -261,6 +269,9 @@ struct scsi_target {
                                                  * means no lun present. */
         unsigned int            no_report_luns:1;       /* Don't use
                                                  * REPORT LUNS for scanning. */
+        unsigned int            expecting_lun_change:1; /* A device has reported
+                                                 * a 3F/0E UA, other devices on
+                                                 * the same target will also. */
         /* commands actually active on LLD. protected by host lock. */
         unsigned int            target_busy;
         /*