[Qemu-devel] [PATCH 4/5] virtio-blk: Drop bounce buffer from dataplane code

[Fam Zheng <famz@redhat.com>]

The block layer will handle the unaligned request.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 hw/block/dataplane/virtio-blk.c | 23 -----------------------
 include/hw/virtio/virtio-blk.h  |  2 --
 2 files changed, 25 deletions(-)

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 968f824..b88eee9 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -75,14 +75,6 @@ static void complete_rdwr(void *opaque, int ret)
 
     trace_virtio_blk_data_plane_complete_request(req->s, req->elem->index, ret);
 
-    if (req->read && req->bounce_iov.iov_base) {
-        qemu_iovec_from_buf(&req->qiov, 0, req->bounce_iov.iov_base, len);
-    }
-
-    if (req->bounce_iov.iov_base) {
-        qemu_vfree(req->bounce_iov.iov_base);
-    }
-
     qemu_iovec_from_buf(req->inhdr, 0, &hdr, sizeof(hdr));
     qemu_iovec_destroy(req->inhdr);
     g_slice_free(QEMUIOVector, req->inhdr);
@@ -142,21 +134,6 @@ static void do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
 
     qiov = &req->qiov;
 
-    if (!bdrv_qiov_is_aligned(s->blk->conf.bs, qiov)) {
-        void *bounce_buffer = qemu_blockalign(s->blk->conf.bs, qiov->size);
-
-        /* Populate bounce buffer with data for writes */
-        if (!read) {
-            qemu_iovec_to_buf(qiov, 0, bounce_buffer, qiov->size);
-        }
-
-        /* Redirect I/O to aligned bounce buffer */
-        req->bounce_iov.iov_base = bounce_buffer;
-        req->bounce_iov.iov_len = qiov->size;
-        qemu_iovec_init_external(&req->bounce_qiov, &req->bounce_iov, 1);
-        qiov = &req->bounce_qiov;
-    }
-
     nb_sectors = qiov->size / BDRV_SECTOR_SIZE;
 
     if (read) {
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index d9ff1c9..e406efa 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -146,8 +146,6 @@ typedef struct VirtIOBlockReq {
 #ifdef CONFIG_VIRTIO_BLK_DATA_PLANE
     struct VirtIOBlockDataPlane *s;
     QEMUIOVector *inhdr;            /* iovecs for virtio_blk_inhdr */
-    struct iovec bounce_iov;        /* used if guest buffers are unaligned */
-    QEMUIOVector bounce_qiov;       /* bounce buffer iovecs */
     bool read;                      /* read or write? */
 #endif
 } VirtIOBlockReq;
-- 
1.9.2