scsi_debug: add Capacity Changed Unit Attention

Via sysfs the virtual_gb scsi_debug parameter can be changed while
LUs are in use. If that changes, the 'Capacity data has changed'
Unit Attention is queued on all LUs.

Signed-off-by: Douglas Gilbert <dgilbert@interlog.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 24 insertions, 4 deletions

diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index d337eaa128d0..ee99aca92bca 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -179,7 +179,8 @@ static const char *scsi_debug_version_date = "20141022";
 #define SDEBUG_UA_POR 0         /* Power on, reset, or bus device reset */
 #define SDEBUG_UA_BUS_RESET 1
 #define SDEBUG_UA_MODE_CHANGED 2
-#define SDEBUG_NUM_UAS 3
+#define SDEBUG_UA_CAPACITY_CHANGED 3
+#define SDEBUG_NUM_UAS 4
 
 /* for check_readiness() */
 #define UAS_ONLY 1
@@ -582,6 +583,11 @@ static int check_readiness(struct scsi_cmnd *SCpnt, int uas_only,
                         if (debug)
                                 cp = "mode parameters changed";
                         break;
+                case SDEBUG_UA_CAPACITY_CHANGED:
+                        mk_sense_buffer(SCpnt, UNIT_ATTENTION,
+                                        UA_CHANGED_ASC, CAPACITY_CHANGED_ASCQ);
+                        if (debug)
+                                cp = "capacity data changed";
                 default:
                         pr_warn("%s: unexpected unit attention code=%d\n",
                                 __func__, k);
@@ -3638,16 +3644,30 @@ static ssize_t virtual_gb_show(struct device_driver *ddp, char *buf)
 {
         return scnprintf(buf, PAGE_SIZE, "%d\n", scsi_debug_virtual_gb);
 }
+
 static ssize_t virtual_gb_store(struct device_driver *ddp, const char *buf,
                                 size_t count)
 {
-        int n;
+        int n;
+        bool changed;
 
         if ((count > 0) && (1 == sscanf(buf, "%d", &n)) && (n >= 0)) {
+                changed = (scsi_debug_virtual_gb != n);
                 scsi_debug_virtual_gb = n;
-
                 sdebug_capacity = get_sdebug_capacity();
-
+                if (changed) {
+                        struct sdebug_host_info *sdhp;
+                        struct sdebug_dev_info *dp;
+
+                        list_for_each_entry(sdhp, &sdebug_host_list,
+                                            host_list) {
+                                list_for_each_entry(dp, &sdhp->dev_info_list,
+                                                    dev_list) {
+                                        set_bit(SDEBUG_UA_CAPACITY_CHANGED,
+                                                dp->uas_bm);
+                                }
+                        }
+                }
                 return count;
         }
         return -EINVAL;