[Qemu-devel] [PATCH 5/9] scsi-generic: Separate `sg_io_hdr' initializations

[Alex Pyrgiotis]

Separate the initialization of the `sg_io_hdr' struct in two parts: one
part that fills the struct with sane defaults, and another part that
prepares it for an SG_IO request with DIRECT IO and a single buffer. The
first part can also be reused later on by the code that uses
scatter-gather lists.

Signed-off-by: Alex Pyrgiotis <address@hidden>
Signed-off-by: Dimitris Aragiorgis <address@hidden>

diff --git a/hw/scsi/scsi-generic.c b/hw/scsi/scsi-generic.c
index f24f472..71c0110 100644
--- a/hw/scsi/scsi-generic.c
+++ b/hw/scsi/scsi-generic.c
@@ -58,6 +58,30 @@ typedef struct SCSIGenericReq {
     sg_io_hdr_t io_header;
 } SCSIGenericReq;
 
+/* Fill an io header with sane defaults. */
+static void _init_io_header(SCSIGenericReq *r, int direction)
+{
+    r->io_header.interface_id = 'S';
+    r->io_header.dxfer_direction = direction;
+    r->io_header.dxfer_len = r->buflen;
+    r->io_header.cmdp = r->req.cmd.buf;
+    r->io_header.cmd_len = r->req.cmd.len;
+    r->io_header.mx_sb_len = sizeof(r->req.sense);
+    r->io_header.sbp = r->req.sense;
+    r->io_header.timeout = MAX_UINT;
+    r->io_header.usr_ptr = r;
+}
+
+/* Create an io_header for buf* operations. */
+static void scsi_buf_init_io_header(SCSIGenericReq *r, int direction)
+{
+    _init_io_header(r, direction);
+
+    r->io_header.iovec_count = 0;
+    r->io_header.dxferp = r->buf;
+    r->io_header.flags |= SG_FLAG_DIRECT_IO;
+}
+
 static void scsi_generic_save_request(QEMUFile *f, SCSIRequest *req)
 {
     SCSIGenericReq *r = DO_UPCAST(SCSIGenericReq, req, req);
@@ -155,17 +179,7 @@ static int execute_command(BlockBackend *blk,
                            SCSIGenericReq *r, int direction,
                            BlockCompletionFunc *complete)
 {
-    r->io_header.interface_id = 'S';
-    r->io_header.dxfer_direction = direction;
-    r->io_header.dxferp = r->buf;
-    r->io_header.dxfer_len = r->buflen;
-    r->io_header.cmdp = r->req.cmd.buf;
-    r->io_header.cmd_len = r->req.cmd.len;
-    r->io_header.mx_sb_len = sizeof(r->req.sense);
-    r->io_header.sbp = r->req.sense;
-    r->io_header.timeout = MAX_UINT;
-    r->io_header.usr_ptr = r;
-    r->io_header.flags |= SG_FLAG_DIRECT_IO;
+    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) {
-- 
2.6.2