block/io: refactor save/load vmstate

Like for read/write in a previous commit, drop extra indirection layer,
generate directly bdrv_readv_vmstate() and bdrv_writev_vmstate().

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20200924185414.28642-8-vsementsov@virtuozzo.com>

block/coroutines.h

@@ -57,11 +57,9 @@ bdrv_common_block_status_above(BlockDriverState *bs,
                                int64_t *map,
                                BlockDriverState **file);
 
-int coroutine_fn
-bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
-                   bool is_read);
-int generated_co_wrapper
-bdrv_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
-                bool is_read);
+int coroutine_fn bdrv_co_readv_vmstate(BlockDriverState *bs,
+                                       QEMUIOVector *qiov, int64_t pos);
+int coroutine_fn bdrv_co_writev_vmstate(BlockDriverState *bs,
+                                        QEMUIOVector *qiov, int64_t pos);
 
 #endif /* BLOCK_COROUTINES_INT_H */

block/io.c

@@ -2475,67 +2475,69 @@ int bdrv_is_allocated_above(BlockDriverState *top,
 }
 
 int coroutine_fn
-bdrv_co_rw_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos,
-                   bool is_read)
+bdrv_co_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
 {
     BlockDriver *drv = bs->drv;
     BlockDriverState *child_bs = bdrv_primary_bs(bs);
     int ret = -ENOTSUP;
 
+    if (!drv) {
+        return -ENOMEDIUM;
+    }
+
     bdrv_inc_in_flight(bs);
 
-    if (!drv) {
-        ret = -ENOMEDIUM;
-    } else if (drv->bdrv_load_vmstate) {
-        if (is_read) {
-            ret = drv->bdrv_load_vmstate(bs, qiov, pos);
-        } else {
-            ret = drv->bdrv_save_vmstate(bs, qiov, pos);
-        }
+    if (drv->bdrv_load_vmstate) {
+        ret = drv->bdrv_load_vmstate(bs, qiov, pos);
     } else if (child_bs) {
-        ret = bdrv_co_rw_vmstate(child_bs, qiov, pos, is_read);
+        ret = bdrv_co_readv_vmstate(child_bs, qiov, pos);
     }
 
     bdrv_dec_in_flight(bs);
+
     return ret;
 }
 
-int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
-                      int64_t pos, int size)
+int coroutine_fn
+bdrv_co_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
 {
-    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
-    int ret;
+    BlockDriver *drv = bs->drv;
+    BlockDriverState *child_bs = bdrv_primary_bs(bs);
+    int ret = -ENOTSUP;
 
-    ret = bdrv_writev_vmstate(bs, &qiov, pos);
-    if (ret < 0) {
-        return ret;
+    if (!drv) {
+        return -ENOMEDIUM;
     }
 
-    return size;
-}
+    bdrv_inc_in_flight(bs);
 
-int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
-{
-    return bdrv_rw_vmstate(bs, qiov, pos, false);
+    if (drv->bdrv_save_vmstate) {
+        ret = drv->bdrv_save_vmstate(bs, qiov, pos);
+    } else if (child_bs) {
+        ret = bdrv_co_writev_vmstate(child_bs, qiov, pos);
+    }
+
+    bdrv_dec_in_flight(bs);
+
+    return ret;
 }
 
-int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                       int64_t pos, int size)
 {
     QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
-    int ret;
-
-    ret = bdrv_readv_vmstate(bs, &qiov, pos);
-    if (ret < 0) {
-        return ret;
-    }
+    int ret = bdrv_writev_vmstate(bs, &qiov, pos);
 
-    return size;
+    return ret < 0 ? ret : size;
 }
 
-int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos)
+int bdrv_load_vmstate(BlockDriverState *bs, uint8_t *buf,
+                      int64_t pos, int size)
 {
-    return bdrv_rw_vmstate(bs, qiov, pos, true);
+    QEMUIOVector qiov = QEMU_IOVEC_INIT_BUF(qiov, buf, size);
+    int ret = bdrv_readv_vmstate(bs, &qiov, pos);
+
+    return ret < 0 ? ret : size;
 }
 
 /**************************************************************/

include/block/block.h

@@ -572,8 +572,10 @@ int path_has_protocol(const char *path);
 int path_is_absolute(const char *path);
 char *path_combine(const char *base_path, const char *filename);
 
-int bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
-int bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
+int generated_co_wrapper
+bdrv_readv_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
+int generated_co_wrapper
+bdrv_writev_vmstate(BlockDriverState *bs, QEMUIOVector *qiov, int64_t pos);
 int bdrv_save_vmstate(BlockDriverState *bs, const uint8_t *buf,
                       int64_t pos, int size);