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envelope-from=vsementsov@virtuozzo.com; helo=EUR02-AM5-obe.outbound.protection.outlook.com X-Spam_score_int: -37 X-Spam_score: -3.8 X-Spam_bar: --- X-Spam_report: (-3.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, MSGID_FROM_MTA_HEADER=0.001, NICE_REPLY_A=-1.678, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Reply-to: Vladimir Sementsov-Ogievskiy From: Vladimir Sementsov-Ogievskiy via 04.11.2021 13:38, Hanna Reitz wrote: > bdrv_attach_child_common_abort() restores the parent's AioContext. To > do so, the child (which was supposed to be attached, but is now detached > again by this abort handler) is added to the ignore list for the > AioContext changing functions. > > However, since we modify a BDS's children list in the BdrvChildClass's > .attach and .detach handlers, the child is already effectively detached > from the parent by this point. We do not need to put it into the ignore > list. > > Use this opportunity to clean up the empty line structure: Keep setting > the ignore list, invoking the AioContext function, and freeing the > ignore list in blocks separated by empty lines. > > Signed-off-by: Hanna Reitz Reviewed-by: Vladimir Sementsov-Ogievskiy What comes in my mind, is that now bdrv_replace_child_noperm() is more strong in detaching.. But may be not enough strong: we still have link from the child to parent (child->opaque).. Maybe more correct for BdrvChild object to have no relation with parent after detaching. But than we'll need some GenericParent object (as child->class is mostly about parent, not about child and even not about the edge).. Now GenericParent is "included" into BdrvChild, which represents both GenericParent and Edge objects.. > --- > block.c | 8 +++++--- > 1 file changed, 5 insertions(+), 3 deletions(-) > > diff --git a/block.c b/block.c > index b95f8dcf8f..6d230ad3d1 100644 > --- a/block.c > +++ b/block.c > @@ -2774,14 +2774,16 @@ static void bdrv_attach_child_common_abort(void *opaque) > } > > if (bdrv_child_get_parent_aio_context(child) != s->old_parent_ctx) { > - GSList *ignore = g_slist_prepend(NULL, child); > + GSList *ignore; > > + /* No need to ignore `child`, because it has been detached already */ > + ignore = NULL; > child->klass->can_set_aio_ctx(child, s->old_parent_ctx, &ignore, > &error_abort); > g_slist_free(ignore); > - ignore = g_slist_prepend(NULL, child); > - child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore); > > + ignore = NULL; > + child->klass->set_aio_ctx(child, s->old_parent_ctx, &ignore); > g_slist_free(ignore); > } > > -- Best regards, Vladimir