From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51944) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fUxHT-0004w3-EF for qemu-devel@nongnu.org; Mon, 18 Jun 2018 12:45:28 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fUxHR-0006JQ-T1 for qemu-devel@nongnu.org; Mon, 18 Jun 2018 12:45:27 -0400 From: Kevin Wolf Date: Mon, 18 Jun 2018 18:44:43 +0200 Message-Id: <20180618164504.24488-15-kwolf@redhat.com> In-Reply-To: <20180618164504.24488-1-kwolf@redhat.com> References: <20180618164504.24488-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 14/35] block: Defer .bdrv_drain_begin callback to polling phase List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, qemu-devel@nongnu.org We cannot allow aio_poll() in bdrv_drain_invoke(begin=true) until we're done with propagating the drain through the graph and are doing the single final BDRV_POLL_WHILE(). Just schedule the coroutine with the callback and increase bs->in_flight to make sure that the polling phase will wait for it. Signed-off-by: Kevin Wolf --- block/io.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-) diff --git a/block/io.c b/block/io.c index ffb273708a..e08d53c8a5 100644 --- a/block/io.c +++ b/block/io.c @@ -182,22 +182,40 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque) /* Set data->done before reading bs->wakeup. */ atomic_mb_set(&data->done, true); - bdrv_wakeup(bs); + bdrv_dec_in_flight(bs); + + if (data->begin) { + g_free(data); + } } /* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */ static void bdrv_drain_invoke(BlockDriverState *bs, bool begin) { - BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin}; + BdrvCoDrainData *data; if (!bs->drv || (begin && !bs->drv->bdrv_co_drain_begin) || (!begin && !bs->drv->bdrv_co_drain_end)) { return; } - data.co = qemu_coroutine_create(bdrv_drain_invoke_entry, &data); - bdrv_coroutine_enter(bs, data.co); - BDRV_POLL_WHILE(bs, !data.done); + data = g_new(BdrvCoDrainData, 1); + *data = (BdrvCoDrainData) { + .bs = bs, + .done = false, + .begin = begin + }; + + /* Make sure the driver callback completes during the polling phase for + * drain_begin. */ + bdrv_inc_in_flight(bs); + data->co = qemu_coroutine_create(bdrv_drain_invoke_entry, data); + aio_co_schedule(bdrv_get_aio_context(bs), data->co); + + if (!begin) { + BDRV_POLL_WHILE(bs, !data->done); + g_free(data); + } } /* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */ -- 2.13.6