block: Make .bdrv_load_vmstate() vectored

This brings it in line with .bdrv_save_vmstate().

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

3 files changed, 33 insertions, 11 deletions

diff --git a/block/io.c b/block/io.c
index 72d72109a5..aac9b67d94 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1871,13 +1871,28 @@ int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
 int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
                       int64_t pos, int size)
 {
+    QEMUIOVector qiov;
+    struct iovec iov = {
+        .iov_base   = buf,
+        .iov_len    = size,
+    };
+
+    qemu_iovec_init_external(&qiov, &iov, 1);
+    return bdrv_readv_vmstate(bs, &qiov, pos);
+}
+
+int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
+{
     BlockDriver *drv = bs->drv;
-    if (!drv)
+
+    if (!drv) {
         return -ENOMEDIUM;
-    if (drv->bdrv_load_vmstate)
-        return drv->bdrv_load_vmstate(bs, buf, pos, size);
-    if (bs->file)
-        return bdrv_load_vmstate(bs->file->bs, buf, pos, size);
+    } else if (drv->bdrv_load_vmstate) {
+        return drv->bdrv_load_vmstate(bs, qiov, pos);
+    } else if (bs->file) {
+        return bdrv_readv_vmstate(bs->file->bs, qiov, pos);
+    }
+
     return -ENOTSUP;
 }
 
diff --git a/block/qcow2.c b/block/qcow2.c
index 9de716a524..362ada24f9 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2926,8 +2926,8 @@ static int qcow2_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
     return ret;
 }
 
-static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
-                              int64_t pos, int size)
+static int qcow2_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
+                              int64_t pos)
 {
     BDRVQcow2State *s = bs->opaque;
     bool zero_beyond_eof = bs->zero_beyond_eof;
@@ -2935,7 +2935,7 @@ static int qcow2_load_vmstate(BlockDriverState *bs, uint8_t *buf,
 
     BLKDBG_EVENT(bs->file, BLKDBG_VMSTATE_LOAD);
     bs->zero_beyond_eof = false;
-    ret = bdrv_pread(bs, qcow2_vm_state_offset(s) + pos, buf, size);
+    ret = bdrv_preadv(bs, qcow2_vm_state_offset(s) + pos, qiov);
     bs->zero_beyond_eof = zero_beyond_eof;
 
     return ret;
diff --git a/block/sheepdog.c b/block/sheepdog.c
index 23fbace1f9..ef5d044ab9 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -2784,12 +2784,19 @@ static int sd_save_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
     return ret;
 }
 
-static int sd_load_vmstate(BlockDriverState *bs, uint8_t *data,
-                           int64_t pos, int size)
+static int sd_load_vmstate(BlockDriverState *bs, QEMUIOVector *qiov,
+                           int64_t pos)
 {
     BDRVSheepdogState *s = bs->opaque;
+    void *buf;
+    int ret;
 
-    return do_load_save_vmstate(s, data, pos, size, 1);
+    buf = qemu_blockalign(bs, qiov->size);
+    ret = do_load_save_vmstate(s, buf, pos, qiov->size, 1);
+    qemu_iovec_from_buf(qiov, 0, buf, qiov->size);
+    qemu_vfree(buf);
+
+    return ret;
 }