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From 2e9423c192511fd2704eea357403f6817cb9aae7 Mon Sep 17 00:00:00 2001
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From: Kevin Wolf <kwolf@redhat.com>
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Date: Fri, 14 Sep 2018 10:55:12 +0200
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Subject: [PATCH 21/49] block: Defer .bdrv_drain_begin callback to polling
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phase
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RH-Author: Kevin Wolf <kwolf@redhat.com>
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Message-id: <20180914105540.18077-15-kwolf@redhat.com>
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Patchwork-id: 82166
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O-Subject: [RHV-7.6 qemu-kvm-rhev PATCH 14/42] block: Defer .bdrv_drain_begin callback to polling phase
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Bugzilla: 1601212
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RH-Acked-by: John Snow <jsnow@redhat.com>
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RH-Acked-by: Max Reitz <mreitz@redhat.com>
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RH-Acked-by: Fam Zheng <famz@redhat.com>
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We cannot allow aio_poll() in bdrv_drain_invoke(begin=true) until we're
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done with propagating the drain through the graph and are doing the
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single final BDRV_POLL_WHILE().
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Just schedule the coroutine with the callback and increase bs->in_flight
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to make sure that the polling phase will wait for it.
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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(cherry picked from commit 0109e7e6f83ae5166b81bbd9a4319d60be49985a)
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Signed-off-by: Kevin Wolf <kwolf@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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block/io.c | 28 +++++++++++++++++++++++-----
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1 file changed, 23 insertions(+), 5 deletions(-)
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diff --git a/block/io.c b/block/io.c
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index 9c41ff9..23fe069 100644
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--- a/block/io.c
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+++ b/block/io.c
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@@ -181,22 +181,40 @@ static void coroutine_fn bdrv_drain_invoke_entry(void *opaque)
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/* Set data->done before reading bs->wakeup. */
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atomic_mb_set(&data->done, true);
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- bdrv_wakeup(bs);
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+ bdrv_dec_in_flight(bs);
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+
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+ if (data->begin) {
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+ g_free(data);
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+ }
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}
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/* Recursively call BlockDriver.bdrv_co_drain_begin/end callbacks */
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static void bdrv_drain_invoke(BlockDriverState *bs, bool begin)
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{
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- BdrvCoDrainData data = { .bs = bs, .done = false, .begin = begin};
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+ BdrvCoDrainData *data;
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if (!bs->drv || (begin && !bs->drv->bdrv_co_drain_begin) ||
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(!begin && !bs->drv->bdrv_co_drain_end)) {
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return;
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}
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- data.co = qemu_coroutine_create(bdrv_drain_invoke_entry, &data);
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- bdrv_coroutine_enter(bs, data.co);
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- BDRV_POLL_WHILE(bs, !data.done);
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+ data = g_new(BdrvCoDrainData, 1);
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+ *data = (BdrvCoDrainData) {
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+ .bs = bs,
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+ .done = false,
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+ .begin = begin
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+ };
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+
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+ /* Make sure the driver callback completes during the polling phase for
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+ * drain_begin. */
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+ bdrv_inc_in_flight(bs);
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+ data->co = qemu_coroutine_create(bdrv_drain_invoke_entry, data);
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+ aio_co_schedule(bdrv_get_aio_context(bs), data->co);
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+
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+ if (!begin) {
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+ BDRV_POLL_WHILE(bs, !data->done);
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+ g_free(data);
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+ }
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}
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/* Returns true if BDRV_POLL_WHILE() should go into a blocking aio_poll() */
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--
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1.8.3.1
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