From 88b062c2036cfd05b5111147736a08ba05ea05a9 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Thu, 27 Oct 2016 12:48:55 +0200 Subject: [PATCH] block: introduce BDRV_POLL_WHILE We want the BDS event loop to run exclusively in the iothread that owns the BDS's AioContext. This macro will provide the synchronization between the two event loops; for now it just wraps the common idiom of a while loop around aio_poll. Signed-off-by: Paolo Bonzini Reviewed-by: Fam Zheng Message-Id: <1477565348-5458-8-git-send-email-pbonzini@redhat.com> Signed-off-by: Fam Zheng --- block/block-backend.c | 7 +------ block/io.c | 37 +++++-------------------------------- block/qed-table.c | 16 ++++------------ include/block/block.h | 9 +++++++++ 4 files changed, 19 insertions(+), 50 deletions(-) diff --git a/block/block-backend.c b/block/block-backend.c index bd6316c32a..27a7f6f523 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -878,7 +878,6 @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf, int64_t bytes, CoroutineEntry co_entry, BdrvRequestFlags flags) { - AioContext *aio_context; QEMUIOVector qiov; struct iovec iov; Coroutine *co; @@ -900,11 +899,7 @@ static int blk_prw(BlockBackend *blk, int64_t offset, uint8_t *buf, co = qemu_coroutine_create(co_entry, &rwco); qemu_coroutine_enter(co); - - aio_context = blk_get_aio_context(blk); - while (rwco.ret == NOT_DONE) { - aio_poll(aio_context, true); - } + BDRV_POLL_WHILE(blk_bs(blk), rwco.ret == NOT_DONE); return rwco.ret; } diff --git a/block/io.c b/block/io.c index afa53b10bc..6fc0145864 100644 --- a/block/io.c +++ b/block/io.c @@ -156,23 +156,12 @@ bool bdrv_requests_pending(BlockDriverState *bs) return false; } -static bool bdrv_drain_poll(BlockDriverState *bs) -{ - bool waited = false; - - while (atomic_read(&bs->in_flight) > 0) { - aio_poll(bdrv_get_aio_context(bs), true); - waited = true; - } - return waited; -} - static bool bdrv_drain_recurse(BlockDriverState *bs) { BdrvChild *child; bool waited; - waited = bdrv_drain_poll(bs); + waited = BDRV_POLL_WHILE(bs, atomic_read(&bs->in_flight) > 0); if (bs->drv && bs->drv->bdrv_drain) { bs->drv->bdrv_drain(bs); @@ -597,13 +586,9 @@ static int bdrv_prwv_co(BdrvChild *child, int64_t offset, /* Fast-path if already in coroutine context */ bdrv_rw_co_entry(&rwco); } else { - AioContext *aio_context = bdrv_get_aio_context(child->bs); - co = qemu_coroutine_create(bdrv_rw_co_entry, &rwco); qemu_coroutine_enter(co); - while (rwco.ret == NOT_DONE) { - aio_poll(aio_context, true); - } + BDRV_POLL_WHILE(child->bs, rwco.ret == NOT_DONE); } return rwco.ret; } @@ -1845,14 +1830,10 @@ int64_t bdrv_get_block_status_above(BlockDriverState *bs, /* Fast-path if already in coroutine context */ bdrv_get_block_status_above_co_entry(&data); } else { - AioContext *aio_context = bdrv_get_aio_context(bs); - co = qemu_coroutine_create(bdrv_get_block_status_above_co_entry, &data); qemu_coroutine_enter(co); - while (!data.done) { - aio_poll(aio_context, true); - } + BDRV_POLL_WHILE(bs, !data.done); } return data.ret; } @@ -2379,13 +2360,9 @@ int bdrv_flush(BlockDriverState *bs) /* Fast-path if already in coroutine context */ bdrv_flush_co_entry(&flush_co); } else { - AioContext *aio_context = bdrv_get_aio_context(bs); - co = qemu_coroutine_create(bdrv_flush_co_entry, &flush_co); qemu_coroutine_enter(co); - while (flush_co.ret == NOT_DONE) { - aio_poll(aio_context, true); - } + BDRV_POLL_WHILE(bs, flush_co.ret == NOT_DONE); } return flush_co.ret; @@ -2511,13 +2488,9 @@ int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int count) /* Fast-path if already in coroutine context */ bdrv_pdiscard_co_entry(&rwco); } else { - AioContext *aio_context = bdrv_get_aio_context(bs); - co = qemu_coroutine_create(bdrv_pdiscard_co_entry, &rwco); qemu_coroutine_enter(co); - while (rwco.ret == NOT_DONE) { - aio_poll(aio_context, true); - } + BDRV_POLL_WHILE(bs, rwco.ret == NOT_DONE); } return rwco.ret; diff --git a/block/qed-table.c b/block/qed-table.c index 1a731dff51..ed443e2b70 100644 --- a/block/qed-table.c +++ b/block/qed-table.c @@ -174,9 +174,7 @@ int qed_read_l1_table_sync(BDRVQEDState *s) qed_read_table(s, s->header.l1_table_offset, s->l1_table, qed_sync_cb, &ret); - while (ret == -EINPROGRESS) { - aio_poll(bdrv_get_aio_context(s->bs), true); - } + BDRV_POLL_WHILE(s->bs, ret == -EINPROGRESS); return ret; } @@ -195,9 +193,7 @@ int qed_write_l1_table_sync(BDRVQEDState *s, unsigned int index, int ret = -EINPROGRESS; qed_write_l1_table(s, index, n, qed_sync_cb, &ret); - while (ret == -EINPROGRESS) { - aio_poll(bdrv_get_aio_context(s->bs), true); - } + BDRV_POLL_WHILE(s->bs, ret == -EINPROGRESS); return ret; } @@ -268,9 +264,7 @@ int qed_read_l2_table_sync(BDRVQEDState *s, QEDRequest *request, uint64_t offset int ret = -EINPROGRESS; qed_read_l2_table(s, request, offset, qed_sync_cb, &ret); - while (ret == -EINPROGRESS) { - aio_poll(bdrv_get_aio_context(s->bs), true); - } + BDRV_POLL_WHILE(s->bs, ret == -EINPROGRESS); return ret; } @@ -290,9 +284,7 @@ int qed_write_l2_table_sync(BDRVQEDState *s, QEDRequest *request, int ret = -EINPROGRESS; qed_write_l2_table(s, request, index, n, flush, qed_sync_cb, &ret); - while (ret == -EINPROGRESS) { - aio_poll(bdrv_get_aio_context(s->bs), true); - } + BDRV_POLL_WHILE(s->bs, ret == -EINPROGRESS); return ret; } diff --git a/include/block/block.h b/include/block/block.h index 398a050176..a9d7c0d82e 100644 --- a/include/block/block.h +++ b/include/block/block.h @@ -334,6 +334,15 @@ void bdrv_drain(BlockDriverState *bs); void coroutine_fn bdrv_co_drain(BlockDriverState *bs); void bdrv_drain_all(void); +#define BDRV_POLL_WHILE(bs, cond) ({ \ + bool waited_ = false; \ + BlockDriverState *bs_ = (bs); \ + while ((cond)) { \ + aio_poll(bdrv_get_aio_context(bs_), true); \ + waited_ = true; \ + } \ + waited_; }) + int bdrv_pdiscard(BlockDriverState *bs, int64_t offset, int count); int bdrv_co_pdiscard(BlockDriverState *bs, int64_t offset, int count); int bdrv_has_zero_init_1(BlockDriverState *bs);