block: Convert bdrv_debug_event() to co_wrapper_mixed

bdrv_debug_event() is categorized as an I/O function, and it currently
doesn't run in a coroutine. We should let it take a graph rdlock since
it traverses the block nodes graph, which however is only possible in a
coroutine.

Therefore turn it into a co_wrapper_mixed to move the actual function
into a coroutine where the lock can be taken.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-14-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

@@ -6351,14 +6351,14 @@ 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();
-    if (!bs || !bs->drv || !bs->drv->bdrv_debug_event) {
+    if (!bs || !bs->drv || !bs->drv->bdrv_co_debug_event) {
         return;
     }
 
-    bs->drv->bdrv_debug_event(bs, event);
+    bs->drv->bdrv_co_debug_event(bs, event);
 }
 
 static BlockDriverState *bdrv_find_debug_node(BlockDriverState *bs)

block/blkdebug.c

@@ -836,7 +836,8 @@ static void process_rule(BlockDriverState *bs, struct BlkdebugRule *rule,
     }
 }
 
-static void blkdebug_debug_event(BlockDriverState *bs, BlkdebugEvent event)
+static void coroutine_fn
+blkdebug_co_debug_event(BlockDriverState *bs, BlkdebugEvent event)
 {
     BDRVBlkdebugState *s = bs->opaque;
     struct BlkdebugRule *rule, *next;
@@ -1086,7 +1087,7 @@ static BlockDriver bdrv_blkdebug = {
     .bdrv_co_pdiscard       = blkdebug_co_pdiscard,
     .bdrv_co_block_status   = blkdebug_co_block_status,
 
-    .bdrv_debug_event           = blkdebug_debug_event,
+    .bdrv_co_debug_event        = blkdebug_co_debug_event,
     .bdrv_debug_breakpoint      = blkdebug_debug_breakpoint,
     .bdrv_debug_remove_breakpoint
                                 = blkdebug_debug_remove_breakpoint,

block/io.c

@@ -1251,7 +1251,7 @@ 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
@@ -1496,10 +1496,10 @@ 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);
@@ -1507,10 +1507,10 @@ 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) {
@@ -1521,7 +1521,7 @@ 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,
@@ -1529,7 +1529,7 @@ 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:
@@ -1931,16 +1931,16 @@ 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;
@@ -1963,7 +1963,7 @@ 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;

include/block/block-io.h

@@ -191,7 +191,10 @@ 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 co_wrapper_mixed bdrv_debug_event(BlockDriverState *bs,
+                                       BlkdebugEvent event);
 
 #define BLKDBG_EVENT(child, evt) \
     do { \

include/block/block_int-common.h

@@ -725,7 +725,8 @@ struct BlockDriver {
     int coroutine_fn GRAPH_RDLOCK_PTR (*bdrv_co_check)(
         BlockDriverState *bs, BdrvCheckResult *result, BdrvCheckMode fix);
 
-    void (*bdrv_debug_event)(BlockDriverState *bs, BlkdebugEvent event);
+    void coroutine_fn (*bdrv_co_debug_event)(BlockDriverState *bs,
+                                             BlkdebugEvent event);
 
     /* io queue for linux-aio */
     void coroutine_fn (*bdrv_co_io_plug)(BlockDriverState *bs);