[SLOF] [PATCH v1 03/27] virtio-blk: add helpers for filling descriptors

[Nikunj A Dadhania]

Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
---
 lib/libvirtio/virtio-blk.c | 29 ++++++++++++++---------------
 lib/libvirtio/virtio.c     | 10 ++++++++++
 lib/libvirtio/virtio.h     |  3 +++
 3 files changed, 27 insertions(+), 15 deletions(-)

diff --git a/lib/libvirtio/virtio-blk.c b/lib/libvirtio/virtio-blk.c
index 826f2ea..b8c4da2 100644
--- a/lib/libvirtio/virtio-blk.c
+++ b/lib/libvirtio/virtio-blk.c
@@ -77,6 +77,13 @@ virtioblk_shutdown(struct virtio_device *dev)
 	virtio_reset_device(dev);
 }
 
+static void fill_blk_hdr(struct virtio_blk_req *blkhdr,
+			 uint32_t type, uint32_t ioprio, uint32_t sector)
+{
+	blkhdr->type = type;
+	blkhdr->ioprio = ioprio;
+	blkhdr->sector = sector;
+}
 
 /**
  * Read blocks
@@ -132,33 +139,25 @@ virtioblk_read(struct virtio_device *dev, char *buf, long blocknum, long cnt)
 	current_used_idx = &vq_used->idx;
 
 	/* Set up header */
-	blkhdr.type = VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER;
-	blkhdr.ioprio = 1;
-	blkhdr.sector = blocknum * blk_size / DEFAULT_SECTOR_SIZE;
+	fill_blk_hdr(&blkhdr, VIRTIO_BLK_T_IN | VIRTIO_BLK_T_BARRIER,
+		     1, blocknum * blk_size / DEFAULT_SECTOR_SIZE);
 
 	/* Determine descriptor index */
 	id = (vq_avail->idx * 3) % vq_size;
 
 	/* Set up virtqueue descriptor for header */
 	desc = &vq_desc[id];
-	desc->addr = (uint64_t)&blkhdr;
-	desc->len = sizeof(struct virtio_blk_req);
-	desc->flags = VRING_DESC_F_NEXT;
-	desc->next = (id + 1) % vq_size;
+	virtio_fill_desc(desc, (uint64_t)&blkhdr, sizeof(struct virtio_blk_req),
+		  VRING_DESC_F_NEXT, (id + 1) % vq_size);
 
 	/* Set up virtqueue descriptor for data */
 	desc = &vq_desc[(id + 1) % vq_size];
-	desc->addr = (uint64_t)buf;
-	desc->len = cnt * blk_size;
-	desc->flags = VRING_DESC_F_NEXT | VRING_DESC_F_WRITE;
-	desc->next = (id + 2) % vq_size;
+	virtio_fill_desc(desc, (uint64_t)buf, cnt * blk_size,
+		  VRING_DESC_F_NEXT | VRING_DESC_F_WRITE, (id + 2) % vq_size);
 
 	/* Set up virtqueue descriptor for status */
 	desc = &vq_desc[(id + 2) % vq_size];
-	desc->addr = (uint64_t)&status;
-	desc->len = 1;
-	desc->flags = VRING_DESC_F_WRITE;
-	desc->next = 0;
+	virtio_fill_desc(desc, (uint64_t)&status, 1, VRING_DESC_F_WRITE, 0);
 
 	vq_avail->ring[vq_avail->idx % vq_size] = id;
 	mb();
diff --git a/lib/libvirtio/virtio.c b/lib/libvirtio/virtio.c
index f9c00a6..8094e3a 100644
--- a/lib/libvirtio/virtio.c
+++ b/lib/libvirtio/virtio.c
@@ -109,6 +109,16 @@ struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int queue)
 }
 
 
+void virtio_fill_desc(struct vring_desc *desc,
+                      uint64_t addr, uint32_t len,
+                      uint16_t flags, uint16_t next)
+{
+	desc->addr = addr;
+	desc->len = len;
+	desc->flags = flags;
+	desc->next = next;
+}
+
 /**
  * Reset virtio device
  */
diff --git a/lib/libvirtio/virtio.h b/lib/libvirtio/virtio.h
index d5759b4..9293d19 100644
--- a/lib/libvirtio/virtio.h
+++ b/lib/libvirtio/virtio.h
@@ -75,6 +75,9 @@ extern int virtio_get_qsize(struct virtio_device *dev, int queue);
 extern struct vring_desc *virtio_get_vring_desc(struct virtio_device *dev, int queue);
 extern struct vring_avail *virtio_get_vring_avail(struct virtio_device *dev, int queue);
 extern struct vring_used *virtio_get_vring_used(struct virtio_device *dev, int queue);
+extern void virtio_fill_desc(struct vring_desc *desc,
+                             uint64_t addr, uint32_t len,
+                             uint16_t flags, uint16_t next);
 
 extern void virtio_reset_device(struct virtio_device *dev);
 extern void virtio_queue_notify(struct virtio_device *dev, int queue);
-- 
2.5.0