[Qemu-devel] [PATCH 10/10] block: Use bdrv_co_* instead of synchronous versions in coroutines

[Kevin Wolf <kwolf@redhat.com>]

If we're already in a coroutine, there is no reason to use the synchronous
version of block layer functions when a coroutine one exists. This makes
bdrv_read/write/flush use bdrv_co_* when used inside a coroutine.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block.c |   43 +++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 43 insertions(+), 0 deletions(-)

diff --git a/block.c b/block.c
index 39819e9..e2075d4 100644
--- a/block.c
+++ b/block.c
@@ -70,6 +70,7 @@ static int coroutine_fn bdrv_co_readv_em(BlockDriverState *bs,
 static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
                                          int64_t sector_num, int nb_sectors,
                                          QEMUIOVector *iov);
+static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs);
 
 static QTAILQ_HEAD(, BlockDriverState) bdrv_states =
     QTAILQ_HEAD_INITIALIZER(bdrv_states);
@@ -950,6 +951,17 @@ int bdrv_read(BlockDriverState *bs, int64_t sector_num,
 {
     BlockDriver *drv = bs->drv;
 
+    if (qemu_in_coroutine()) {
+        QEMUIOVector qiov;
+        struct iovec iov = {
+            .iov_base = (void *)buf,
+            .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
+        };
+
+        qemu_iovec_init_external(&qiov, &iov, 1);
+        return bdrv_co_readv(bs, sector_num, nb_sectors, &qiov);
+    }
+
     if (!drv)
         return -ENOMEDIUM;
     if (bdrv_check_request(bs, sector_num, nb_sectors))
@@ -996,6 +1008,18 @@ int bdrv_write(BlockDriverState *bs, int64_t sector_num,
                const uint8_t *buf, int nb_sectors)
 {
     BlockDriver *drv = bs->drv;
+
+    if (qemu_in_coroutine()) {
+        QEMUIOVector qiov;
+        struct iovec iov = {
+            .iov_base = (void *)buf,
+            .iov_len = nb_sectors * BDRV_SECTOR_SIZE,
+        };
+
+        qemu_iovec_init_external(&qiov, &iov, 1);
+        return bdrv_co_writev(bs, sector_num, nb_sectors, &qiov);
+    }
+
     if (!bs->drv)
         return -ENOMEDIUM;
     if (bs->read_only)
@@ -1661,6 +1685,10 @@ int bdrv_flush(BlockDriverState *bs)
         return 0;
     }
 
+    if (qemu_in_coroutine()) {
+        return bdrv_co_flush_em(bs);
+    }
+
     if (bs->drv && bs->drv->bdrv_flush) {
         return bs->drv->bdrv_flush(bs);
     }
@@ -2929,6 +2957,21 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs,
     return bdrv_co_io_em(bs, sector_num, nb_sectors, iov, true);
 }
 
+static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs)
+{
+    CoroutineIOCompletion co = {
+        .coroutine = qemu_coroutine_self(),
+    };
+    BlockDriverAIOCB *acb;
+
+    acb = bdrv_aio_flush(bs, bdrv_co_io_em_complete, &co);
+    if (!acb) {
+        return -EIO;
+    }
+    qemu_coroutine_yield();
+    return co.ret;
+}
+
 /**************************************************************/
 /* removable device support */
 
-- 
1.7.6