scsi: introduce scsi_req_continue

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>

hw/esp.c

@@ -253,11 +253,10 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
         s->dma_counter = 0;
         if (datalen > 0) {
             s->rregs[ESP_RSTAT] |= STAT_DI;
-            s->current_dev->info->read_data(s->current_req);
         } else {
             s->rregs[ESP_RSTAT] |= STAT_DO;
-            s->current_dev->info->write_data(s->current_req);
         }
+        scsi_req_continue(s->current_req);
     }
     s->rregs[ESP_RINTR] = INTR_BS | INTR_FC;
     s->rregs[ESP_RSEQ] = SEQ_CD;
@@ -383,22 +382,17 @@ static void esp_do_dma(ESPState *s)
     else
         s->ti_size -= len;
     if (s->async_len == 0) {
-        if (to_device) {
+        scsi_req_continue(s->current_req);
-            // ti_size is negative
-            s->current_dev->info->write_data(s->current_req);
-        } else {
-            s->current_dev->info->read_data(s->current_req);
         /* If there is still data to be read from the device then
            complete the DMA operation immediately.  Otherwise defer
            until the scsi layer has completed.  */
-            if (s->dma_left == 0 && s->ti_size > 0) {
+        if (to_device || s->dma_left != 0 || s->ti_size == 0) {
-                esp_dma_done(s);
+            return;
         }
     }
-    } else {
+
     /* Partially filled a scsi buffer. Complete immediately.  */
     esp_dma_done(s);
-    }
 }
 
 static void esp_command_complete(SCSIRequest *req, int reason, uint32_t arg)

hw/lsi53c895a.c

@@ -580,13 +580,7 @@ static void lsi_do_dma(LSIState *s, int out)
     s->current->dma_len -= count;
     if (s->current->dma_len == 0) {
         s->current->dma_buf = NULL;
-        if (out) {
+        scsi_req_continue(s->current->req);
-            /* Write the data.  */
-            dev->info->write_data(s->current->req);
-        } else {
-            /* Request any remaining data.  */
-            dev->info->read_data(s->current->req);
-        }
     } else {
         s->current->dma_buf += count;
         lsi_resume_script(s);
@@ -791,14 +785,14 @@ static void lsi_do_command(LSIState *s)
     s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun);
 
     n = scsi_req_enqueue(s->current->req, buf);
+    if (n) {
         if (n > 0) {
             lsi_set_phase(s, PHASE_DI);
-        dev->info->read_data(s->current->req);
         } else if (n < 0) {
             lsi_set_phase(s, PHASE_DO);
-        dev->info->write_data(s->current->req);
         }
-
+        scsi_req_continue(s->current->req);
+    }
     if (!s->command_complete) {
         if (n) {
             /* Command did not complete immediately so disconnect.  */

hw/scsi-bus.c

@@ -602,11 +602,21 @@ void scsi_req_unref(SCSIRequest *req)
     }
 }
 
+/* Tell the device that we finished processing this chunk of I/O.  It
+   will start the next chunk or complete the command.  */
+void scsi_req_continue(SCSIRequest *req)
+{
+    trace_scsi_req_continue(req->dev->id, req->lun, req->tag);
+    if (req->cmd.mode == SCSI_XFER_TO_DEV) {
+        req->dev->info->write_data(req);
+    } else {
+        req->dev->info->read_data(req);
+    }
+}
+
 /* Called by the devices when data is ready for the HBA.  The HBA should
    start a DMA operation to read or fill the device's data buffer.
-   Once it completes, calling one of req->dev->info->read_data or
+   Once it completes, calling scsi_req_continue will restart I/O.  */
-   req->dev->info->write_data (depending on the direction of the
-   transfer) will restart I/O.  */
 void scsi_req_data(SCSIRequest *req, int len)
 {
     trace_scsi_req_data(req->dev->id, req->lun, req->tag, len);

hw/scsi.h

@@ -151,6 +151,7 @@ void scsi_req_unref(SCSIRequest *req);
 
 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_abort(SCSIRequest *req, int status);

hw/spapr_vscsi.c

@@ -448,7 +448,6 @@ static int vscsi_preprocess_desc(vscsi_req *req)
 
 static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
 {
-    SCSIDevice *sdev = req->sdev;
     uint8_t *cdb = req->iu.srp.cmd.cdb;
     int n;
 
@@ -469,7 +468,7 @@ static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
     } else if (n == 0) {
         return;
     }
-    sdev->info->read_data(req->sreq);
+    scsi_req_continue(req->sreq);
 }
 
 /* Callback to indicate that the SCSI layer has completed a transfer.  */
@@ -508,7 +507,7 @@ static void vscsi_command_complete(SCSIRequest *sreq, int reason, uint32_t arg)
                     buf[12], buf[13], buf[14], buf[15]);
             memcpy(req->sense, buf, len);
             req->senselen = len;
-            sdev->info->read_data(sreq);
+            scsi_req_continue(req->sreq);
         }
         return;
     }
@@ -552,11 +551,7 @@ static void vscsi_command_complete(SCSIRequest *sreq, int reason, uint32_t arg)
 
     /* Start next chunk */
     req->data_len -= rc;
-    if (req->writing) {
+    scsi_req_continue(sreq);
-        sdev->info->write_data(sreq);
-    } else {
-        sdev->info->read_data(sreq);
-    }
 }
 
 static void vscsi_request_cancelled(SCSIRequest *sreq)
@@ -667,15 +662,14 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
 
         /* Preprocess RDMA descriptors */
         vscsi_preprocess_desc(req);
-    }
 
         /* Get transfer direction and initiate transfer */
         if (n > 0) {
             req->data_len = n;
-        sdev->info->read_data(req->sreq);
         } else if (n < 0) {
             req->data_len = -n;
-        sdev->info->write_data(req->sreq);
+        }
+        scsi_req_continue(req->sreq);
     }
     /* Don't touch req here, it may have been recycled already */
 

hw/usb-msd.c

@@ -190,11 +190,7 @@ static void usb_msd_copy_data(MSDState *s)
     s->scsi_buf += len;
     s->data_len -= len;
     if (s->scsi_len == 0 || s->data_len == 0) {
-        if (s->mode == USB_MSDM_DATAIN) {
+        scsi_req_continue(s->req);
-            s->scsi_dev->info->read_data(s->req);
-        } else if (s->mode == USB_MSDM_DATAOUT) {
-            s->scsi_dev->info->write_data(s->req);
-        }
     }
 }
 
@@ -249,6 +245,7 @@ static void usb_msd_command_complete(SCSIRequest *req, int reason, uint32_t arg)
         s->req = NULL;
         return;
     }
+    assert((s->mode == USB_MSDM_DATAOUT) == (req->cmd.mode == SCSI_XFER_TO_DEV));
     s->scsi_len = arg;
     s->scsi_buf = s->scsi_dev->info->get_buf(req);
     if (p) {
@@ -381,12 +378,8 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
             scsi_req_enqueue(s->req, cbw.cmd);
             /* ??? Should check that USB and SCSI data transfer
                directions match.  */
-            if (s->residue == 0) {
+            if (s->mode != USB_MSDM_CSW && s->residue == 0) {
-                if (s->mode == USB_MSDM_DATAIN) {
+                scsi_req_continue(s->req);
-                    s->scsi_dev->info->read_data(s->req);
-                } else if (s->mode == USB_MSDM_DATAOUT) {
-                    s->scsi_dev->info->write_data(s->req);
-                }
             }
             ret = len;
             break;

trace-events

@@ -209,6 +209,7 @@ disable usb_set_device_feature(int addr, int feature, int ret) "dev %d, feature
 disable scsi_req_alloc(int target, int lun, int tag) "target %d lun %d tag %d"
 disable scsi_req_data(int target, int lun, int tag, int len) "target %d lun %d tag %d len %d"
 disable scsi_req_dequeue(int target, int lun, int tag) "target %d lun %d tag %d"
+disable scsi_req_continue(int target, int lun, int tag) "target %d lun %d tag %d"
 disable scsi_req_parsed(int target, int lun, int tag, int cmd, int mode, int xfer, uint64_t lba) "target %d lun %d tag %d command %d dir %d length %d lba %"PRIu64""
 disable scsi_req_parse_bad(int target, int lun, int tag, int cmd) "target %d lun %d tag %d command %d"