From f24196d388ec781ce3ae99c1fb78ba9755785f91 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Mon, 6 May 2019 17:27:39 +0300 Subject: [PATCH] qcow2: qcow2_co_preadv: improve locking Background: decryption will be done in threads, to take benefit of it, we should move it out of the lock first. But let's go further: it turns out, that only qcow2_get_cluster_offset() needs locking, so reduce locking to it. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20190506142741.41731-7-vsementsov@virtuozzo.com Reviewed-by: Alberto Garcia Signed-off-by: Max Reitz --- block/qcow2.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) diff --git a/block/qcow2.c b/block/qcow2.c index 1413df1389..4a89850389 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1969,8 +1969,6 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, qemu_iovec_init(&hd_qiov, qiov->niov); - qemu_co_mutex_lock(&s->lock); - while (bytes != 0) { /* prepare next request */ @@ -1980,7 +1978,9 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, QCOW_MAX_CRYPT_CLUSTERS * s->cluster_size); } + qemu_co_mutex_lock(&s->lock); ret = qcow2_get_cluster_offset(bs, offset, &cur_bytes, &cluster_offset); + qemu_co_mutex_unlock(&s->lock); if (ret < 0) { goto fail; } @@ -1995,10 +1995,8 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, if (bs->backing) { BLKDBG_EVENT(bs->file, BLKDBG_READ_BACKING_AIO); - qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_preadv(bs->backing, offset, cur_bytes, &hd_qiov, 0); - qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } @@ -2014,11 +2012,9 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, break; case QCOW2_CLUSTER_COMPRESSED: - qemu_co_mutex_unlock(&s->lock); ret = qcow2_co_preadv_compressed(bs, cluster_offset, offset, cur_bytes, &hd_qiov); - qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } @@ -2055,11 +2051,9 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, } BLKDBG_EVENT(bs->file, BLKDBG_READ_AIO); - qemu_co_mutex_unlock(&s->lock); ret = bdrv_co_preadv(s->data_file, cluster_offset + offset_in_cluster, cur_bytes, &hd_qiov, 0); - qemu_co_mutex_lock(&s->lock); if (ret < 0) { goto fail; } @@ -2094,8 +2088,6 @@ static coroutine_fn int qcow2_co_preadv(BlockDriverState *bs, uint64_t offset, ret = 0; fail: - qemu_co_mutex_unlock(&s->lock); - qemu_iovec_destroy(&hd_qiov); qemu_vfree(cluster_data); -- 2.11.4.GIT