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bh=Q4Vnj6oBPJEBsdh78JffL2RsD5I0M/JGFxJ+1Q6n0PI=; b=ZaawgheYBSJTPHxhEB+Ld5x3ckTD/cLmuj7MWpXGHwoC68UrN+a4Xo+51qwdaB3Nas264I VbGsm1MKXIK7uMZecm4M3Jn15S17NjPXvLgyTYOjWUION6OZBYm9y10FwgyzRVLLdadjLV rbdbI9YYPko7ATc3ucyucJ+9lqRhsm4= X-MC-Unique: yYCQOGfLOu2LshR2va399A-1 From: peterx@redhat.com To: Peter Maydell , qemu-devel@nongnu.org Cc: peterx@redhat.com, Fabiano Rosas Subject: [PULL 30/34] migration/multifd: Unify multifd and TLS connection paths Date: Thu, 8 Feb 2024 11:05:24 +0800 Message-ID: <20240208030528.368214-31-peterx@redhat.com> In-Reply-To: <20240208030528.368214-1-peterx@redhat.com> References: <20240208030528.368214-1-peterx@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.9 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=peterx@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.106, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 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+importer=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1707361709964100011 Content-Type: text/plain; charset="utf-8" From: Fabiano Rosas During multifd channel creation (multifd_send_new_channel_async) when TLS is enabled, the multifd_channel_connect function is called twice, once to create the TLS handshake thread and another time after the asynchrounous TLS handshake has finished. This creates a slightly confusing call stack where multifd_channel_connect() is called more times than the number of channels. It also splits error handling between the two callers of multifd_channel_connect() causing some code duplication. Lastly, it gets in the way of having a single point to determine whether all channel creation tasks have been initiated. Refactor the code to move the reentrancy one level up at the multifd_new_send_channel_async() level, de-duplicating the error handling and allowing for the next patch to introduce a synchronization point common to all the multifd channel creation, regardless of TLS. Note that the previous code would never fail once p->c had been set. This patch changes this assumption, which affects refcounting, so add comments around object_unref to explain the situation. Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240206215118.6171-6-farosas@suse.de Signed-off-by: Peter Xu --- migration/multifd.c | 83 ++++++++++++++++++++++----------------------- 1 file changed, 40 insertions(+), 43 deletions(-) diff --git a/migration/multifd.c b/migration/multifd.c index cf865edba0..3db18dc79e 100644 --- a/migration/multifd.c +++ b/migration/multifd.c @@ -869,30 +869,7 @@ out: return NULL; } =20 -static bool multifd_channel_connect(MultiFDSendParams *p, - QIOChannel *ioc, - Error **errp); - -static void multifd_tls_outgoing_handshake(QIOTask *task, - gpointer opaque) -{ - MultiFDSendParams *p =3D opaque; - QIOChannel *ioc =3D QIO_CHANNEL(qio_task_get_source(task)); - Error *err =3D NULL; - - if (!qio_task_propagate_error(task, &err)) { - trace_multifd_tls_outgoing_handshake_complete(ioc); - if (multifd_channel_connect(p, ioc, &err)) { - return; - } - } - - trace_multifd_tls_outgoing_handshake_error(ioc, error_get_pretty(err)); - - multifd_send_set_error(err); - multifd_send_kick_main(p); - error_free(err); -} +static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque); =20 static void *multifd_tls_handshake_thread(void *opaque) { @@ -900,7 +877,7 @@ static void *multifd_tls_handshake_thread(void *opaque) QIOChannelTLS *tioc =3D QIO_CHANNEL_TLS(p->c); =20 qio_channel_tls_handshake(tioc, - multifd_tls_outgoing_handshake, + multifd_new_send_channel_async, p, NULL, NULL); @@ -920,6 +897,10 @@ static bool multifd_tls_channel_connect(MultiFDSendPar= ams *p, return false; } =20 + /* + * Ownership of the socket channel now transfers to the newly + * created TLS channel, which has already taken a reference. + */ object_unref(OBJECT(ioc)); trace_multifd_tls_outgoing_handshake_start(ioc, tioc, hostname); qio_channel_set_name(QIO_CHANNEL(tioc), "multifd-tls-outgoing"); @@ -936,18 +917,7 @@ static bool multifd_channel_connect(MultiFDSendParams = *p, QIOChannel *ioc, Error **errp) { - trace_multifd_set_outgoing_channel( - ioc, object_get_typename(OBJECT(ioc)), - migrate_get_current()->hostname); - - if (migrate_channel_requires_tls_upgrade(ioc)) { - /* - * tls_channel_connect will call back to this - * function after the TLS handshake, - * so we mustn't call multifd_send_thread until then - */ - return multifd_tls_channel_connect(p, ioc, errp); - } + qio_channel_set_delay(ioc, false); =20 migration_ioc_register_yank(ioc); p->registered_yank =3D true; @@ -959,24 +929,51 @@ static bool multifd_channel_connect(MultiFDSendParams= *p, return true; } =20 +/* + * When TLS is enabled this function is called once to establish the + * TLS connection and a second time after the TLS handshake to create + * the multifd channel. Without TLS it goes straight into the channel + * creation. + */ static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque) { MultiFDSendParams *p =3D opaque; QIOChannel *ioc =3D QIO_CHANNEL(qio_task_get_source(task)); Error *local_err =3D NULL; + bool ret; =20 trace_multifd_new_send_channel_async(p->id); - if (!qio_task_propagate_error(task, &local_err)) { - qio_channel_set_delay(ioc, false); - if (multifd_channel_connect(p, ioc, &local_err)) { - return; - } + + if (qio_task_propagate_error(task, &local_err)) { + ret =3D false; + goto out; + } + + trace_multifd_set_outgoing_channel(ioc, object_get_typename(OBJECT(ioc= )), + migrate_get_current()->hostname); + + if (migrate_channel_requires_tls_upgrade(ioc)) { + ret =3D multifd_tls_channel_connect(p, ioc, &local_err); + } else { + ret =3D multifd_channel_connect(p, ioc, &local_err); } =20 + if (ret) { + return; + } + +out: trace_multifd_new_send_channel_async_error(p->id, local_err); multifd_send_set_error(local_err); multifd_send_kick_main(p); - object_unref(OBJECT(ioc)); + if (!p->c) { + /* + * If no channel has been created, drop the initial + * reference. Otherwise cleanup happens at + * multifd_send_channel_destroy() + */ + object_unref(OBJECT(ioc)); + } error_free(local_err); } =20 --=20 2.43.0