block: Add blk_[co_]preadv_part()

Implement blk_preadv_part() using generated_co_wrapper.

Signed-off-by: Alberto Faria <afaria@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20220705161527.1054072-9-afaria@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>

1 files changed, 23 insertions, 7 deletions

diff --git a/block/block-backend.c b/block/block-backend.c
index 4d6c18b..49db3f6 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1280,9 +1280,10 @@ static void coroutine_fn blk_wait_while_drained(BlockBackend *blk)
 }
 
 /* To be called between exactly one pair of blk_inc/dec_in_flight() */
-int coroutine_fn
-blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
-                 QEMUIOVector *qiov, BdrvRequestFlags flags)
+static int coroutine_fn
+blk_co_do_preadv_part(BlockBackend *blk, int64_t offset, int64_t bytes,
+                      QEMUIOVector *qiov, size_t qiov_offset,
+                      BdrvRequestFlags flags)
 {
     int ret;
     BlockDriverState *bs;
@@ -1307,7 +1308,8 @@ blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
                 bytes, false);
     }
 
-    ret = bdrv_co_preadv(blk->root, offset, bytes, qiov, flags);
+    ret = bdrv_co_preadv_part(blk->root, offset, bytes, qiov, qiov_offset,
+                              flags);
     bdrv_dec_in_flight(bs);
     return ret;
 }
@@ -1320,7 +1322,21 @@ int coroutine_fn blk_co_preadv(BlockBackend *blk, int64_t offset,
     IO_OR_GS_CODE();
 
     blk_inc_in_flight(blk);
-    ret = blk_co_do_preadv(blk, offset, bytes, qiov, flags);
+    ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, 0, flags);
+    blk_dec_in_flight(blk);
+
+    return ret;
+}
+
+int coroutine_fn blk_co_preadv_part(BlockBackend *blk, int64_t offset,
+                                    int64_t bytes, QEMUIOVector *qiov,
+                                    size_t qiov_offset, BdrvRequestFlags flags)
+{
+    int ret;
+    IO_OR_GS_CODE();
+
+    blk_inc_in_flight(blk);
+    ret = blk_co_do_preadv_part(blk, offset, bytes, qiov, qiov_offset, flags);
     blk_dec_in_flight(blk);
 
     return ret;
@@ -1537,8 +1553,8 @@ static void blk_aio_read_entry(void *opaque)
     QEMUIOVector *qiov = rwco->iobuf;
 
     assert(qiov->size == acb->bytes);
-    rwco->ret = blk_co_do_preadv(rwco->blk, rwco->offset, acb->bytes,
-                                 qiov, rwco->flags);
+    rwco->ret = blk_co_do_preadv_part(rwco->blk, rwco->offset, acb->bytes, qiov,
+                                      0, rwco->flags);
     blk_aio_complete(acb);
 }