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Mon, 17 May 2021 03:05:53 -0700 (PDT) Received: from avogadro.lan ([2001:b07:6468:f312:63a7:c72e:ea0e:6045]) by smtp.gmail.com with ESMTPSA id h9sm10659926ede.93.2021.05.17.03.05.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 May 2021 03:05:52 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Subject: [PATCH v2 3/6] coroutine-sleep: allow qemu_co_sleep_wake that wakes nothing Date: Mon, 17 May 2021 12:05:45 +0200 Message-Id: <20210517100548.28806-4-pbonzini@redhat.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210517100548.28806-1-pbonzini@redhat.com> References: <20210517100548.28806-1-pbonzini@redhat.com> MIME-Version: 1.0 Received-SPF: pass client-ip=2a00:1450:4864:20::530; envelope-from=paolo.bonzini@gmail.com; helo=mail-ed1-x530.google.com X-Spam_score_int: -14 X-Spam_score: -1.5 X-Spam_bar: - X-Spam_report: (-1.5 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=0.25, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=0.249, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: eesposit@redhat.com, vsementsov@virtuozzo.com, stefanha@redhat.com, qemu-block@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" All callers of qemu_co_sleep_wake are checking whether they are passing a NULL argument inside the pointer-to-pointer: do the check in qemu_co_sleep_wake itself. As a side effect, qemu_co_sleep_wake can be called more than once and it will only wake the coroutine once; after the first time, the argument will be set to NULL via *sleep_state->user_state_pointer. However, this would not be safe unless co_sleep_cb keeps using the QemuCoSleepState* directly, so make it go through the pointer-to-pointer instead. Reviewed-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Paolo Bonzini --- block/block-copy.c | 4 +--- block/nbd.c | 8 ++------ util/qemu-coroutine-sleep.c | 21 ++++++++++++--------- 3 files changed, 15 insertions(+), 18 deletions(-) diff --git a/block/block-copy.c b/block/block-copy.c index 9b4af00614..f896dc56f2 100644 --- a/block/block-copy.c +++ b/block/block-copy.c @@ -674,9 +674,7 @@ out: void block_copy_kick(BlockCopyCallState *call_state) { - if (call_state->sleep_state) { - qemu_co_sleep_wake(call_state->sleep_state); - } + qemu_co_sleep_wake(call_state->sleep_state); } /* diff --git a/block/nbd.c b/block/nbd.c index 1d4668d42d..1c6315b168 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -289,9 +289,7 @@ static void coroutine_fn nbd_client_co_drain_begin(BlockDriverState *bs) BDRVNBDState *s = (BDRVNBDState *)bs->opaque; s->drained = true; - if (s->connection_co_sleep_ns_state) { - qemu_co_sleep_wake(s->connection_co_sleep_ns_state); - } + qemu_co_sleep_wake(s->connection_co_sleep_ns_state); nbd_co_establish_connection_cancel(bs, false); @@ -330,9 +328,7 @@ static void nbd_teardown_connection(BlockDriverState *bs) s->state = NBD_CLIENT_QUIT; if (s->connection_co) { - if (s->connection_co_sleep_ns_state) { - qemu_co_sleep_wake(s->connection_co_sleep_ns_state); - } + qemu_co_sleep_wake(s->connection_co_sleep_ns_state); nbd_co_establish_connection_cancel(bs, true); } if (qemu_in_coroutine()) { diff --git a/util/qemu-coroutine-sleep.c b/util/qemu-coroutine-sleep.c index 3f6f637e81..3ae2b5399a 100644 --- a/util/qemu-coroutine-sleep.c +++ b/util/qemu-coroutine-sleep.c @@ -27,19 +27,22 @@ struct QemuCoSleepState { void qemu_co_sleep_wake(QemuCoSleepState *sleep_state) { - /* Write of schedule protected by barrier write in aio_co_schedule */ - const char *scheduled = qatomic_cmpxchg(&sleep_state->co->scheduled, - qemu_co_sleep_ns__scheduled, NULL); + if (sleep_state) { + /* Write of schedule protected by barrier write in aio_co_schedule */ + const char *scheduled = qatomic_cmpxchg(&sleep_state->co->scheduled, + qemu_co_sleep_ns__scheduled, NULL); - assert(scheduled == qemu_co_sleep_ns__scheduled); - *sleep_state->user_state_pointer = NULL; - timer_del(&sleep_state->ts); - aio_co_wake(sleep_state->co); + assert(scheduled == qemu_co_sleep_ns__scheduled); + *sleep_state->user_state_pointer = NULL; + timer_del(&sleep_state->ts); + aio_co_wake(sleep_state->co); + } } static void co_sleep_cb(void *opaque) { - qemu_co_sleep_wake(opaque); + QemuCoSleepState **sleep_state = opaque; + qemu_co_sleep_wake(*sleep_state); } void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns, @@ -60,7 +63,7 @@ void coroutine_fn qemu_co_sleep_ns_wakeable(QEMUClockType type, int64_t ns, abort(); } - aio_timer_init(ctx, &state.ts, type, SCALE_NS, co_sleep_cb, &state); + aio_timer_init(ctx, &state.ts, type, SCALE_NS, co_sleep_cb, sleep_state); *sleep_state = &state; timer_mod(&state.ts, qemu_clock_get_ns(type) + ns); qemu_coroutine_yield();