[PATCH v2 8/8] block: do not take AioContext around reopen

[Emanuele Giuseppe Esposito]

Reopen needs to handle AioContext carefully due to calling
bdrv_drain_all_begin/end.  By not taking AioContext around calls to
bdrv_reopen_multiple, we can drop the function's release/acquire
pair and the AioContext argument too.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 block/block-backend.c |  4 ----
 block/mirror.c        |  9 ---------
 blockdev.c            | 19 ++++++-------------
 3 files changed, 6 insertions(+), 26 deletions(-)

diff --git a/block/block-backend.c b/block/block-backend.c
index 413af51f3b..6fdc698e9e 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -2291,20 +2291,16 @@ int blk_commit_all(void)
     BlockBackend *blk = NULL;
 
     while ((blk = blk_all_next(blk)) != NULL) {
-        AioContext *aio_context = blk_get_aio_context(blk);
         BlockDriverState *unfiltered_bs = bdrv_skip_filters(blk_bs(blk));
 
-        aio_context_acquire(aio_context);
         if (blk_is_inserted(blk) && bdrv_cow_child(unfiltered_bs)) {
             int ret;
 
             ret = bdrv_commit(unfiltered_bs);
             if (ret < 0) {
-                aio_context_release(aio_context);
                 return ret;
             }
         }
-        aio_context_release(aio_context);
     }
     return 0;
 }
diff --git a/block/mirror.c b/block/mirror.c
index 5a71bd8bbc..43174bbc6b 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -631,7 +631,6 @@ static int mirror_exit_common(Job *job)
     MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
     BlockJob *bjob = &s->common;
     MirrorBDSOpaque *bs_opaque;
-    AioContext *replace_aio_context = NULL;
     BlockDriverState *src;
     BlockDriverState *target_bs;
     BlockDriverState *mirror_top_bs;
@@ -699,11 +698,6 @@ static int mirror_exit_common(Job *job)
         }
     }
 
-    if (s->to_replace) {
-        replace_aio_context = bdrv_get_aio_context(s->to_replace);
-        aio_context_acquire(replace_aio_context);
-    }
-
     if (s->should_complete && !abort) {
         BlockDriverState *to_replace = s->to_replace ?: src;
         bool ro = bdrv_is_read_only(to_replace);
@@ -740,9 +734,6 @@ static int mirror_exit_common(Job *job)
         error_free(s->replace_blocker);
         bdrv_unref(s->to_replace);
     }
-    if (replace_aio_context) {
-        aio_context_release(replace_aio_context);
-    }
     g_free(s->replaces);
     bdrv_unref(target_bs);
 
diff --git a/blockdev.c b/blockdev.c
index e901107344..1672ef756e 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -3469,7 +3469,6 @@ void qmp_change_backing_file(const char *device,
                              Error **errp)
 {
     BlockDriverState *bs = NULL;
-    AioContext *aio_context;
     BlockDriverState *image_bs = NULL;
     Error *local_err = NULL;
     bool ro;
@@ -3480,37 +3479,34 @@ void qmp_change_backing_file(const char *device,
         return;
     }
 
-    aio_context = bdrv_get_aio_context(bs);
-    aio_context_acquire(aio_context);
-
     image_bs = bdrv_lookup_bs(NULL, image_node_name, &local_err);
     if (local_err) {
         error_propagate(errp, local_err);
-        goto out;
+        return;
     }
 
     if (!image_bs) {
         error_setg(errp, "image file not found");
-        goto out;
+        return;
     }
 
     if (bdrv_find_base(image_bs) == image_bs) {
         error_setg(errp, "not allowing backing file change on an image "
                          "without a backing file");
-        goto out;
+        return;
     }
 
     /* even though we are not necessarily operating on bs, we need it to
      * determine if block ops are currently prohibited on the chain */
     if (bdrv_op_is_blocked(bs, BLOCK_OP_TYPE_CHANGE, errp)) {
-        goto out;
+        return;
     }
 
     /* final sanity check */
     if (!bdrv_chain_contains(bs, image_bs)) {
         error_setg(errp, "'%s' and image file are not in the same chain",
                    device);
-        goto out;
+        return;
     }
 
     /* if not r/w, reopen to make r/w */
@@ -3518,7 +3514,7 @@ void qmp_change_backing_file(const char *device,
 
     if (ro) {
         if (bdrv_reopen_set_read_only(image_bs, false, errp) != 0) {
-            goto out;
+            return;
         }
     }
 
@@ -3536,9 +3532,6 @@ void qmp_change_backing_file(const char *device,
     if (ro) {
         bdrv_reopen_set_read_only(image_bs, true, errp);
     }
-
-out:
-    aio_context_release(aio_context);
 }
 
 void qmp_blockdev_add(BlockdevOptions *options, Error **errp)
-- 
2.30.2