[PATCH 12/15] block: limit bdrv_co_yield_to_drain to drain_begin

[Paolo Bonzini]

Since bdrv_drained_end does not poll anymore, it need not jump out of
coroutine context.  This in turn enables the removal of the "begin"
field in BdrvCoDrainData.

Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
 block/io.c | 19 +++----------------
 1 file changed, 3 insertions(+), 16 deletions(-)

diff --git a/block/io.c b/block/io.c
index f4444b7777d9..695c8f3f5faa 100644
--- a/block/io.c
+++ b/block/io.c
@@ -233,7 +233,6 @@ typedef struct {
     Coroutine *co;
     BlockDriverState *bs;
     bool done;
-    bool begin;
     bool poll;
     BdrvChild *parent;
 } BdrvCoDrainData;
@@ -275,15 +274,9 @@ static void bdrv_co_drain_bh_cb(void *opaque)
         AioContext *ctx = bdrv_get_aio_context(bs);
         aio_context_acquire(ctx);
         bdrv_dec_in_flight(bs);
-        if (data->begin) {
-            bdrv_do_drained_begin(bs, data->parent, data->poll);
-        } else {
-            assert(!data->poll);
-            bdrv_do_drained_end(bs, data->parent);
-        }
+        bdrv_do_drained_begin(bs, data->parent, data->poll);
         aio_context_release(ctx);
     } else {
-        assert(data->begin);
         bdrv_drain_all_begin();
     }
 
@@ -292,7 +285,6 @@ static void bdrv_co_drain_bh_cb(void *opaque)
 }
 
 static void coroutine_fn bdrv_co_yield_to_drain(BlockDriverState *bs,
-                                                bool begin,
                                                 BdrvChild *parent,
                                                 bool poll)
 {
@@ -309,7 +301,6 @@ static void coroutine_fn 
bdrv_co_yield_to_drain(BlockDriverState *bs,
         .co = self,
         .bs = bs,
         .done = false,
-        .begin = begin,
         .parent = parent,
         .poll = poll,
     };
@@ -348,7 +339,7 @@ static void bdrv_do_drained_begin(BlockDriverState *bs, 
BdrvChild *parent,
     IO_OR_GS_CODE();
 
     if (qemu_in_coroutine()) {
-        bdrv_co_yield_to_drain(bs, true, parent, poll);
+        bdrv_co_yield_to_drain(bs, parent, poll);
         return;
     }
 
@@ -394,10 +385,6 @@ static void bdrv_do_drained_end(BlockDriverState *bs, 
BdrvChild *parent)
 {
     int old_quiesce_counter;
 
-    if (qemu_in_coroutine()) {
-        bdrv_co_yield_to_drain(bs, false, parent, false);
-        return;
-    }
     assert(bs->quiesce_counter > 0);
 
     /* Re-enable things in child-to-parent order */
@@ -472,7 +459,7 @@ void bdrv_drain_all_begin(void)
     GLOBAL_STATE_CODE();
 
     if (qemu_in_coroutine()) {
-        bdrv_co_yield_to_drain(NULL, true, NULL, true);
+        bdrv_co_yield_to_drain(NULL, NULL, true);
         return;
     }
 
-- 
2.38.1