[PATCH 12/15] block: convert bdrv_debug_event in generated_co_wrapper

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

BlockDriver->bdrv_debug_event is categorized as IO callback, and
it currently doesn't run in a coroutine.
This makes very difficult to add the graph rdlock, since the
callback traverses the block nodes graph.

Therefore use generated_co_wrapper to automatically
create a wrapper with the same name.
Unfortunately we cannot use a generated_co_wrapper_simple,
because the function is called by mixed functions that run both
in coroutine and non-coroutine context (for example blkdebug_open).

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block.c                          |  4 +++-
 block/io.c                       | 22 +++++++++++-----------
 include/block/block-io.h         |  7 +++++--
 include/block/block_int-common.h |  4 +++-
 4 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/block.c b/block.c
index afc5735b82..a2e3550d5c 100644
--- a/block.c
+++ b/block.c
@@ -6331,9 +6331,11 @@ BlockStatsSpecific *bdrv_get_specific_stats(BlockDriverState *bs)
     return drv->bdrv_get_specific_stats(bs);
 }
 
-void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event)
+void coroutine_fn bdrv_co_debug_event(BlockDriverState *bs, BlkdebugEvent event)
 {
     IO_CODE();
+    assert_bdrv_graph_readable();
+
     if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
         return;
     }
diff --git a/block/io.c b/block/io.c
index 88da9470c3..11d2c5dcde 100644
--- a/block/io.c
+++ b/block/io.c
@@ -1227,7 +1227,7 @@ static int coroutine_fn bdrv_co_do_copy_on_readv(BdrvChild *child,
                 goto err;
             }
 
-            bdrv_debug_event(bs, BLKDBG_COR_WRITE);
+            bdrv_co_debug_event(bs, BLKDBG_COR_WRITE);
             if (drv->bdrv_co_pwrite_zeroes &&
                 buffer_is_zero(bounce_buffer, pnum)) {
                 /* FIXME: Should we (perhaps conditionally) be setting
@@ -1472,10 +1472,10 @@ static coroutine_fn int bdrv_padding_rmw_read(BdrvChild *child,
         qemu_iovec_init_buf(&local_qiov, pad->buf, bytes);
 
         if (pad->head) {
-            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
+            bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_HEAD);
         }
         if (pad->merge_reads && pad->tail) {
-            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
+            bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
         }
         ret = bdrv_aligned_preadv(child, req, req->overlap_offset, bytes,
                                   align, &local_qiov, 0, 0);
@@ -1483,10 +1483,10 @@ static coroutine_fn int bdrv_padding_rmw_read(BdrvChild *child,
             return ret;
         }
         if (pad->head) {
-            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
+            bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_HEAD);
         }
         if (pad->merge_reads && pad->tail) {
-            bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+            bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
         }
 
         if (pad->merge_reads) {
@@ -1497,7 +1497,7 @@ static coroutine_fn int bdrv_padding_rmw_read(BdrvChild *child,
     if (pad->tail) {
         qemu_iovec_init_buf(&local_qiov, pad->tail_buf, align);
 
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
+        bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_TAIL);
         ret = bdrv_aligned_preadv(
                 child, req,
                 req->overlap_offset + req->overlap_bytes - align,
@@ -1505,7 +1505,7 @@ static coroutine_fn int bdrv_padding_rmw_read(BdrvChild *child,
         if (ret < 0) {
             return ret;
         }
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
+        bdrv_co_debug_event(bs, BLKDBG_PWRITEV_RMW_AFTER_TAIL);
     }
 
 zero_mem:
@@ -1908,16 +1908,16 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
     if (ret < 0) {
         /* Do nothing, write notifier decided to fail this request */
     } else if (flags & BDRV_REQ_ZERO_WRITE) {
-        bdrv_debug_event(bs, BLKDBG_PWRITEV_ZERO);
+        bdrv_co_debug_event(bs, BLKDBG_PWRITEV_ZERO);
         ret = bdrv_co_do_pwrite_zeroes(bs, offset, bytes, flags);
     } else if (flags & BDRV_REQ_WRITE_COMPRESSED) {
         ret = bdrv_driver_pwritev_compressed(bs, offset, bytes,
                                              qiov, qiov_offset);
     } else if (bytes <= max_transfer) {
-        bdrv_debug_event(bs, BLKDBG_PWRITEV);
+        bdrv_co_debug_event(bs, BLKDBG_PWRITEV);
         ret = bdrv_driver_pwritev(bs, offset, bytes, qiov, qiov_offset, flags);
     } else {
-        bdrv_debug_event(bs, BLKDBG_PWRITEV);
+        bdrv_co_debug_event(bs, BLKDBG_PWRITEV);
         while (bytes_remaining) {
             int num = MIN(bytes_remaining, max_transfer);
             int local_flags = flags;
@@ -1940,7 +1940,7 @@ static int coroutine_fn bdrv_aligned_pwritev(BdrvChild *child,
             bytes_remaining -= num;
         }
     }
-    bdrv_debug_event(bs, BLKDBG_PWRITEV_DONE);
+    bdrv_co_debug_event(bs, BLKDBG_PWRITEV_DONE);
 
     if (ret >= 0) {
         ret = 0;
diff --git a/include/block/block-io.h b/include/block/block-io.h
index 497580fc28..176e3cc734 100644
--- a/include/block/block-io.h
+++ b/include/block/block-io.h
@@ -170,12 +170,15 @@ void *qemu_try_blockalign0(BlockDriverState *bs, size_t size);
 void bdrv_enable_copy_on_read(BlockDriverState *bs);
 void bdrv_disable_copy_on_read(BlockDriverState *bs);
 
-void bdrv_debug_event(BlockDriverState *bs, BlkdebugEvent event);
+void coroutine_fn bdrv_co_debug_event(BlockDriverState *bs,
+                                      BlkdebugEvent event);
+void generated_co_wrapper bdrv_debug_event(BlockDriverState *bs,
+                                                  BlkdebugEvent event);
 
 #define BLKDBG_EVENT(child, evt) \
     do { \
         if (child) { \
-            bdrv_debug_event(child->bs, evt); \
+            bdrv_co_debug_event(child->bs, evt); \
         } \
     } while (0)
 
diff --git a/include/block/block_int-common.h b/include/block/block_int-common.h
index 3e1eba518c..b509855c19 100644
--- a/include/block/block_int-common.h
+++ b/include/block/block_int-common.h
@@ -781,7 +781,9 @@ struct BlockDriver {
                                       BdrvCheckResult *result,
                                       BdrvCheckMode fix);
 
-    void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);
+    /* Called with graph rdlock taken. */
+    void coroutine_fn (*bdrv_debug_event)(BlockDriverState *bs,
+                                          BlkdebugEvent event);
 
     /* io queue for linux-aio */
     void (*bdrv_io_plug)(BlockDriverState *bs);
-- 
2.31.1