scsi: pass status when completing

A small improvement in the SCSI request API.  Pass the status
at the time the request is completed, so that we can assert that
no request is completed twice.  This would have detected the
problem fixed in the previous patch.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

4 files changed, 25 insertions, 31 deletions

diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index d1ef55985d..9637ccb52e 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -682,9 +682,10 @@ void scsi_req_print(SCSIRequest *req)
     }
 }
 
-void scsi_req_complete(SCSIRequest *req)
+void scsi_req_complete(SCSIRequest *req, int status)
 {
-    assert(req->status != -1);
+    assert(req->status == -1);
+    req->status = status;
     scsi_req_ref(req);
     scsi_req_dequeue(req);
     req->bus->ops->complete(req, req->status);
@@ -706,11 +707,10 @@ void scsi_req_cancel(SCSIRequest *req)
 
 void scsi_req_abort(SCSIRequest *req, int status)
 {
-    req->status = status;
     if (req->dev && req->dev->info->cancel_io) {
         req->dev->info->cancel_io(req);
     }
-    scsi_req_complete(req);
+    scsi_req_complete(req, status);
 }
 
 void scsi_device_purge_requests(SCSIDevice *sdev)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index e38d9f0b75..38ebe042cb 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -102,21 +102,15 @@ static void scsi_disk_clear_sense(SCSIDiskState *s)
     memset(&s->sense, 0, sizeof(s->sense));
 }
 
-static void scsi_req_set_status(SCSIDiskReq *r, int status, SCSISense sense)
-{
-    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
-
-    r->req.status = status;
-    s->sense = sense;
-}
-
 /* Helper function for command completion.  */
 static void scsi_command_complete(SCSIDiskReq *r, int status, SCSISense sense)
 {
+    SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, r->req.dev);
+
     DPRINTF("Command complete tag=0x%x status=%d sense=%d/%d/%d\n",
             r->req.tag, status, sense.key, sense.asc, sense.ascq);
-    scsi_req_set_status(r, status, sense);
-    scsi_req_complete(&r->req);
+    s->sense = sense;
+    scsi_req_complete(&r->req, status);
 }
 
 /* Cancel a pending data transfer.  */
@@ -969,7 +963,6 @@ static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf)
         scsi_command_complete(r, CHECK_CONDITION, SENSE_CODE(INVALID_OPCODE));
         return -1;
     }
-    scsi_req_set_status(r, GOOD, SENSE_CODE(NO_SENSE));
     return buflen;
 
 not_ready:
diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index 7b0026eb98..71cbfb0a44 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -115,6 +115,7 @@ static void scsi_free_request(SCSIRequest *req)
 /* Helper function for command completion.  */
 static void scsi_command_complete(void *opaque, int ret)
 {
+    int status;
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
     SCSIGenericState *s = DO_UPCAST(SCSIGenericState, qdev, r->req.dev);
 
@@ -126,36 +127,37 @@ static void scsi_command_complete(void *opaque, int ret)
     if (ret != 0) {
         switch (ret) {
         case -EDOM:
-            r->req.status = TASK_SET_FULL;
+            status = TASK_SET_FULL;
             break;
         case -EINVAL:
-            r->req.status = CHECK_CONDITION;
+            status = CHECK_CONDITION;
             scsi_set_sense(s, SENSE_CODE(INVALID_FIELD));
             break;
         case -ENOMEM:
-            r->req.status = CHECK_CONDITION;
+            status = CHECK_CONDITION;
             scsi_set_sense(s, SENSE_CODE(TARGET_FAILURE));
             break;
         default:
-            r->req.status = CHECK_CONDITION;
+            status = CHECK_CONDITION;
             scsi_set_sense(s, SENSE_CODE(IO_ERROR));
             break;
         }
     } else {
         if (s->driver_status & SG_ERR_DRIVER_TIMEOUT) {
-            r->req.status = BUSY;
+            status = BUSY;
             BADF("Driver Timeout\n");
-        } else if (r->io_header.status)
-            r->req.status = r->io_header.status;
-        else if (s->driver_status & SG_ERR_DRIVER_SENSE)
-            r->req.status = CHECK_CONDITION;
-        else
-            r->req.status = GOOD;
+        } else if (r->io_header.status) {
+            status = r->io_header.status;
+        } else if (s->driver_status & SG_ERR_DRIVER_SENSE) {
+            status = CHECK_CONDITION;
+        } else {
+            status = GOOD;
+        }
     }
     DPRINTF("Command complete 0x%p tag=0x%x status=%d\n",
-            r, r->req.tag, r->req.status);
+            r, r->req.tag, status);
 
-    scsi_req_complete(&r->req);
+    scsi_req_complete(&r->req, status);
 }
 
 /* Cancel a pending data transfer.  */
@@ -341,8 +343,7 @@ static int32_t scsi_send_command(SCSIRequest *req, uint8_t *cmd)
     if (cmd[0] != REQUEST_SENSE && req->lun != s->lun) {
         DPRINTF("Unimplemented LUN %d\n", req->lun);
         scsi_set_sense(s, SENSE_CODE(LUN_NOT_SUPPORTED));
-        r->req.status = CHECK_CONDITION;
-        scsi_req_complete(&r->req);
+        scsi_req_complete(&r->req, CHECK_CONDITION);
         return 0;
     }
 
diff --git a/hw/scsi.h b/hw/scsi.h
index 6b15bbc2cd..18d3643da1 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -153,7 +153,7 @@ int scsi_req_parse(SCSIRequest *req, uint8_t *buf);
 void scsi_req_print(SCSIRequest *req);
 void scsi_req_continue(SCSIRequest *req);
 void scsi_req_data(SCSIRequest *req, int len);
-void scsi_req_complete(SCSIRequest *req);
+void scsi_req_complete(SCSIRequest *req, int status);
 uint8_t *scsi_req_get_buf(SCSIRequest *req);
 int scsi_req_get_sense(SCSIRequest *req, uint8_t *buf, int len);
 void scsi_req_abort(SCSIRequest *req, int status);