block/coroutines: I/O and "I/O or GS" API

block coroutines functions run in different aiocontext, and are
not protected by the BQL. Therefore are I/O.

On the other side, generated_co_wrapper functions use BDRV_POLL_WHILE,
meaning the caller can either be the main loop or a specific iothread.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Message-Id: <20220303151616.325444-25-eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 52 insertions, 29 deletions

diff --git a/block/coroutines.h b/block/coroutines.h
index c8c14a29c8..b293e943c8 100644
--- a/block/coroutines.h
+++ b/block/coroutines.h
@@ -30,17 +30,17 @@
 /* For blk_bs() in generated block/block-gen.c */
 #include "sysemu/block-backend.h"
 
+/*
+ * I/O API functions. These functions are thread-safe.
+ *
+ * See include/block/block-io.h for more information about
+ * the I/O API.
+ */
+
 int coroutine_fn bdrv_co_check(BlockDriverState *bs,
                                BdrvCheckResult *res, BdrvCheckMode fix);
 int coroutine_fn bdrv_co_invalidate_cache(BlockDriverState *bs, Error **errp);
 
-int generated_co_wrapper
-bdrv_preadv(BdrvChild *child, int64_t offset, unsigned int bytes,
-            QEMUIOVector *qiov, BdrvRequestFlags flags);
-int generated_co_wrapper
-bdrv_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes,
-             QEMUIOVector *qiov, BdrvRequestFlags flags);
-
 int coroutine_fn
 bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   BlockDriverState *base,
@@ -52,6 +52,51 @@ bdrv_co_common_block_status_above(BlockDriverState *bs,
                                   int64_t *map,
                                   BlockDriverState **file,
                                   int *depth);
+
+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);
+
+int coroutine_fn
+nbd_co_do_establish_connection(BlockDriverState *bs, Error **errp);
+
+
+int coroutine_fn
+blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
+                 QEMUIOVector *qiov, BdrvRequestFlags flags);
+
+
+int coroutine_fn
+blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
+                       QEMUIOVector *qiov, size_t qiov_offset,
+                       BdrvRequestFlags flags);
+
+int coroutine_fn
+blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
+
+int coroutine_fn
+blk_co_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
+
+int coroutine_fn blk_co_do_flush(BlockBackend *blk);
+
+
+/*
+ * "I/O or GS" API functions. These functions can run without
+ * the BQL, but only in one specific iothread/main loop.
+ *
+ * See include/block/block-io.h for more information about
+ * the "I/O or GS" API.
+ */
+
+int generated_co_wrapper
+bdrv_preadv(BdrvChild *child, int64_t offset, unsigned int bytes,
+            QEMUIOVector *qiov, BdrvRequestFlags flags);
+
+int generated_co_wrapper
+bdrv_pwritev(BdrvChild *child, int64_t offset, unsigned int bytes,
+             QEMUIOVector *qiov, BdrvRequestFlags flags);
+
 int generated_co_wrapper
 bdrv_common_block_status_above(BlockDriverState *bs,
                                BlockDriverState *base,
@@ -63,46 +108,24 @@ bdrv_common_block_status_above(BlockDriverState *bs,
                                int64_t *map,
                                BlockDriverState **file,
                                int *depth);
-
-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);
-
 int generated_co_wrapper
 nbd_do_establish_connection(BlockDriverState *bs, Error **errp);
-int coroutine_fn
-nbd_co_do_establish_connection(BlockDriverState *bs, Error **errp);
-
 
 int generated_co_wrapper
 blk_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
               QEMUIOVector *qiov, BdrvRequestFlags flags);
-int coroutine_fn
-blk_co_do_preadv(BlockBackend *blk, int64_t offset, int64_t bytes,
-                 QEMUIOVector *qiov, BdrvRequestFlags flags);
-
 
 int generated_co_wrapper
 blk_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
                     QEMUIOVector *qiov, size_t qiov_offset,
                     BdrvRequestFlags flags);
-int coroutine_fn
-blk_co_do_pwritev_part(BlockBackend *blk, int64_t offset, int64_t bytes,
-                       QEMUIOVector *qiov, size_t qiov_offset,
-                       BdrvRequestFlags flags);
 
 int generated_co_wrapper
 blk_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
-int coroutine_fn
-blk_co_do_ioctl(BlockBackend *blk, unsigned long int req, void *buf);
 
 int generated_co_wrapper
 blk_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
-int coroutine_fn
-blk_co_do_pdiscard(BlockBackend *blk, int64_t offset, int64_t bytes);
 
 int generated_co_wrapper blk_do_flush(BlockBackend *blk);
-int coroutine_fn blk_co_do_flush(BlockBackend *blk);
 
 #endif /* BLOCK_COROUTINES_INT_H */