[Qemu-devel] [PATCH 6/9] scsi-generic: Make request execution buf-specific

[Alex Pyrgiotis <apyrgio@arrikto.com>]

Move the request execution logic from execute_command() to
scsi_buf_do_request(), since the way the io header is initialized and
the ioctl is performed is used only for requests that use an
intermediate buffer.

For now, the above is the only request type, but we need to pave the way
for the support of requests with scatter-gather lists.

Signed-off-by: Alex Pyrgiotis <apyrgio@arrikto.com>
Signed-off-by: Dimitris Aragiorgis <dimara@arrikto.com>

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index 71c0110..8e2058d 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -175,20 +175,6 @@ static void scsi_command_complete(void *opaque, int ret)
     scsi_command_complete_noio(r, ret);
 }
 
-static int execute_command(BlockBackend *blk,
-                           SCSIGenericReq *r, int direction,
-                           BlockCompletionFunc *complete)
-{
-    scsi_buf_init_io_header(r, direction);
-
-    r->req.aiocb = blk_aio_ioctl(blk, SG_IO, &r->io_header, complete, r);
-    if (r->req.aiocb == NULL) {
-        return -EIO;
-    }
-
-    return 0;
-}
-
 static void scsi_buf_read_complete(void *opaque, int ret)
 {
     SCSIGenericReq *r = (SCSIGenericReq *)opaque;
@@ -242,12 +228,33 @@ static void scsi_buf_read_complete(void *opaque, int ret)
     scsi_req_unref(&r->req);
 }
 
+/*
+ * Execute the request using an intermediate buffer.
+ *
+ * This function does the following:
+ *
+ * a. Initialize the io header for the ioctl request.
+ * b. Perform the ioctl request using blk_aio_ioctl().
+ */
+static void scsi_buf_do_request(SCSIGenericReq *r, int direction,
+        BlockCompletionFunc *complete)
+{
+    SCSIDevice *s = r->req.dev;
+
+    scsi_buf_init_io_header(r, direction);
+
+    r->req.aiocb = blk_aio_ioctl(s->conf.blk, SG_IO,
+            &r->io_header, complete, r);
+
+    if (!r->req.aiocb) {
+        scsi_command_complete_noio(r, -EIO);
+    }
+}
+
 /* Read more data from scsi device into buffer.  */
 static void scsi_buf_read_data(SCSIRequest *req)
 {
     SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
-    SCSIDevice *s = r->req.dev;
-    int ret;
 
     DPRINTF("scsi_buf_read_data 0x%x\n", req->tag);
 
@@ -258,11 +265,7 @@ static void scsi_buf_read_data(SCSIRequest *req)
         return;
     }
 
-    ret = execute_command(s->conf.blk, r, SG_DXFER_FROM_DEV,
-                          scsi_buf_read_complete);
-    if (ret < 0) {
-        scsi_command_complete_noio(r, ret);
-    }
+    scsi_buf_do_request(r, SG_DXFER_FROM_DEV, scsi_buf_read_complete);
 }
 
 static void scsi_common_read_data(SCSIRequest *req)
@@ -299,8 +302,6 @@ static void scsi_buf_write_complete(void *opaque, int ret)
 static void scsi_buf_write_data(SCSIRequest *req)
 {
     SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
-    SCSIDevice *s = r->req.dev;
-    int ret;
 
     DPRINTF("scsi_buf_write_data 0x%x\n", req->tag);
     if (r->len == 0) {
@@ -311,11 +312,8 @@ static void scsi_buf_write_data(SCSIRequest *req)
 
     /* The request is used as the AIO opaque value, so add a ref.  */
     scsi_req_ref(&r->req);
-    ret = execute_command(s->conf.blk, r, SG_DXFER_TO_DEV,
-            scsi_buf_write_complete);
-    if (ret < 0) {
-        scsi_command_complete_noio(r, ret);
-    }
+
+    scsi_buf_do_request(r, SG_DXFER_TO_DEV, scsi_buf_write_complete);
 }
 
 static void scsi_common_write_data(SCSIRequest *req)
@@ -339,8 +337,6 @@ static uint8_t *scsi_get_buf(SCSIRequest *req)
 static int32_t scsi_common_send_command(SCSIRequest *req, uint8_t *cmd)
 {
     SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
-    SCSIDevice *s = r->req.dev;
-    int ret;
 
 #ifdef DEBUG_SCSI
     {
@@ -358,12 +354,7 @@ static int32_t scsi_common_send_command(SCSIRequest *req, uint8_t *cmd)
         r->buf = NULL;
         /* The request is used as the AIO opaque value, so add a ref.  */
         scsi_req_ref(&r->req);
-        ret = execute_command(s->conf.blk, r, SG_DXFER_NONE,
-                              scsi_command_complete);
-        if (ret < 0) {
-            scsi_command_complete_noio(r, ret);
-            return 0;
-        }
+        scsi_buf_do_request(r, SG_DXFER_NONE, scsi_command_complete);
         return 0;
     }
 
-- 
2.6.2