scsi: introduce scsi_sense_from_errno()

The new function is an extension of the switch statement in scsi-disk.c
which also includes the errno cases only found in sg_io_sense_from_errno.
This allows us to consolidate the errno handling.

Extracted from a patch by Hannes Reinecke <hare@suse.de>.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

hw/scsi/scsi-disk.c

@@ -194,13 +194,13 @@ static bool scsi_handle_rw_error(SCSIDiskReq *r, int error, bool acct_failed)
     SCSIDiskClass *sdc = (SCSIDiskClass *) object_get_class(OBJECT(s));
     BlockErrorAction action = blk_get_error_action(s->qdev.conf.blk,
                                                    is_read, error);
+    SCSISense sense;
 
     if (action == BLOCK_ERROR_ACTION_REPORT) {
         if (acct_failed) {
             block_acct_failed(blk_get_stats(s->qdev.conf.blk), &r->acct);
         }
-        switch (error) {
-        case 0:
+        if (error == 0) {
             /* A passthrough command has run and has produced sense data; check
              * whether the error has to be handled by the guest or should rather
              * pause the host.
@@ -213,41 +213,12 @@ static bool scsi_handle_rw_error(SCSIDiskReq *r, int error, bool acct_failed)
                 return true;
             }
             error = scsi_sense_buf_to_errno(r->req.sense, sizeof(r->req.sense));
-            break;
-#ifdef CONFIG_LINUX
-            /* These errno mapping are specific to Linux.  For more information:
-             * - scsi_decide_disposition in drivers/scsi/scsi_error.c
-             * - scsi_result_to_blk_status in drivers/scsi/scsi_lib.c
-             * - blk_errors[] in block/blk-core.c
-             */
-        case EBADE:
-            /* DID_NEXUS_FAILURE -> BLK_STS_NEXUS.  */
-            scsi_req_complete(&r->req, RESERVATION_CONFLICT);
-            break;
-        case ENODATA:
-            /* DID_MEDIUM_ERROR -> BLK_STS_MEDIUM.  */
-            scsi_check_condition(r, SENSE_CODE(READ_ERROR));
-            break;
-        case EREMOTEIO:
-            /* DID_TARGET_FAILURE -> BLK_STS_TARGET.  */
-            scsi_req_complete(&r->req, HARDWARE_ERROR);
-            break;
-#endif
-        case ENOMEDIUM:
-            scsi_check_condition(r, SENSE_CODE(NO_MEDIUM));
-            break;
-        case ENOMEM:
-            scsi_check_condition(r, SENSE_CODE(TARGET_FAILURE));
-            break;
-        case EINVAL:
-            scsi_check_condition(r, SENSE_CODE(INVALID_FIELD));
-            break;
-        case ENOSPC:
-            scsi_check_condition(r, SENSE_CODE(SPACE_ALLOC_FAILED));
-            break;
-        default:
-            scsi_check_condition(r, SENSE_CODE(IO_ERROR));
-            break;
+        } else {
+            int status = scsi_sense_from_errno(error, &sense);
+            if (status == CHECK_CONDITION) {
+                scsi_req_build_sense(&r->req, sense);
+            }
+            scsi_req_complete(&r->req, status);
         }
     }
 

include/scsi/utils.h

@@ -135,4 +135,6 @@ int sg_io_sense_from_errno(int errno_value, struct sg_io_hdr *io_hdr,
                            SCSISense *sense);
 #endif
 
+int scsi_sense_from_errno(int errno_value, SCSISense *sense);
+
 #endif

scsi/utils.c

@@ -565,21 +565,52 @@ const char *scsi_command_name(uint8_t cmd)
     return names[cmd];
 }
 
+int scsi_sense_from_errno(int errno_value, SCSISense *sense)
+{
+    switch (errno_value) {
+    case 0:
+        return GOOD;
+    case EDOM:
+        return TASK_SET_FULL;
+#ifdef CONFIG_LINUX
+        /* These errno mapping are specific to Linux.  For more information:
+         * - scsi_decide_disposition in drivers/scsi/scsi_error.c
+         * - scsi_result_to_blk_status in drivers/scsi/scsi_lib.c
+         * - blk_errors[] in block/blk-core.c
+         */
+    case EBADE:
+        return RESERVATION_CONFLICT;
+    case ENODATA:
+        *sense = SENSE_CODE(READ_ERROR);
+        return CHECK_CONDITION;
+    case EREMOTEIO:
+        *sense = SENSE_CODE(LUN_COMM_FAILURE);
+        return CHECK_CONDITION;
+#endif
+    case ENOMEDIUM:
+        *sense = SENSE_CODE(NO_MEDIUM);
+        return CHECK_CONDITION;
+    case ENOMEM:
+        *sense = SENSE_CODE(TARGET_FAILURE);
+        return CHECK_CONDITION;
+    case EINVAL:
+        *sense = SENSE_CODE(INVALID_FIELD);
+        return CHECK_CONDITION;
+    case ENOSPC:
+        *sense = SENSE_CODE(SPACE_ALLOC_FAILED);
+        return CHECK_CONDITION;
+    default:
+        *sense = SENSE_CODE(IO_ERROR);
+        return CHECK_CONDITION;
+    }
+}
+
 #ifdef CONFIG_LINUX
 int sg_io_sense_from_errno(int errno_value, struct sg_io_hdr *io_hdr,
                            SCSISense *sense)
 {
     if (errno_value != 0) {
-        switch (errno_value) {
-        case EDOM:
-            return TASK_SET_FULL;
-        case ENOMEM:
-            *sense = SENSE_CODE(TARGET_FAILURE);
-            return CHECK_CONDITION;
-        default:
-            *sense = SENSE_CODE(IO_ERROR);
-            return CHECK_CONDITION;
-        }
+        return scsi_sense_from_errno(errno_value, sense);
     } else {
         if (io_hdr->host_status == SG_ERR_DID_NO_CONNECT ||
             io_hdr->host_status == SG_ERR_DID_BUS_BUSY ||