block: Convert bdrv_is_inserted() to co_wrapper

bdrv_is_inserted() 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 to move the actual function into a
coroutine where the lock can be taken.

At the same time, add also blk_is_inserted as co_wrapper_mixed, since it
is called in both coroutine and non-coroutine contexts.

Because now this function creates a new coroutine and polls, we need to
take the AioContext lock where it is missing, for the only reason that
internally c_w_mixed_bdrv_rdlock calls AIO_WAIT_WHILE and it expects to
release the AioContext lock. Once the rwlock is ultimated and placed in
every place it needs to be, we will poll using AIO_WAIT_WHILE_UNLOCKED
and remove the AioContext lock.

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20230113204212.359076-5-kwolf@redhat.com>
Reviewed-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/block/file-posix.c b/block/file-posix.c
index 3b112095a4..433a25fc91 100644
--- a/block/file-posix.c
+++ b/block/file-posix.c
@@ -3757,7 +3757,7 @@ out:
     return prio;
 }
 
-static bool cdrom_is_inserted(BlockDriverState *bs)
+static bool coroutine_fn cdrom_co_is_inserted(BlockDriverState *bs)
 {
     BDRVRawState *s = bs->opaque;
     int ret;
@@ -3824,7 +3824,7 @@ static BlockDriver bdrv_host_cdrom = {
                         = raw_get_allocated_file_size,
 
     /* removable device support */
-    .bdrv_is_inserted   = cdrom_is_inserted,
+    .bdrv_co_is_inserted    = cdrom_co_is_inserted,
     .bdrv_eject         = cdrom_eject,
     .bdrv_lock_medium   = cdrom_lock_medium,
 
@@ -3883,7 +3883,7 @@ static int cdrom_reopen(BlockDriverState *bs)
     return 0;
 }
 
-static bool cdrom_is_inserted(BlockDriverState *bs)
+static bool coroutine_fn cdrom_co_is_inserted(BlockDriverState *bs)
 {
     return raw_getlength(bs) > 0;
 }
@@ -3954,7 +3954,7 @@ static BlockDriver bdrv_host_cdrom = {
                         = raw_get_allocated_file_size,
 
     /* removable device support */
-    .bdrv_is_inserted   = cdrom_is_inserted,
+    .bdrv_co_is_inserted     = cdrom_co_is_inserted,
     .bdrv_eject         = cdrom_eject,
     .bdrv_lock_medium   = cdrom_lock_medium,
 };