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[Qemu-devel] [PATCH v6 6/8] qcow2: qcow2_co_preadv: improve locking
From: |
Vladimir Sementsov-Ogievskiy |
Subject: |
[Qemu-devel] [PATCH v6 6/8] qcow2: qcow2_co_preadv: improve locking |
Date: |
Mon, 6 May 2019 17:27:39 +0300 |
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 <address@hidden>
---
block/qcow2.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)
diff --git a/block/qcow2.c b/block/qcow2.c
index 7970d0992a..5954696245 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -1970,8 +1970,6 @@ 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 */
@@ -1981,7 +1979,9 @@ 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;
}
@@ -1996,10 +1996,8 @@ 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;
}
@@ -2015,11 +2013,9 @@ 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;
}
@@ -2056,11 +2052,9 @@ 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;
}
@@ -2095,8 +2089,6 @@ 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);
--
2.18.0
- [Qemu-devel] [PATCH v6 0/8] qcow2: encryption threads, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 2/8] qcow2: add separate file for threaded data processing functions, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 8/8] qcow2: do encryption in threads, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 4/8] qcow2-threads: qcow2_co_do_compress: protect queuing by mutex, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 3/8] qcow2-threads: use thread_pool_submit_co, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 5/8] qcow2-threads: split out generic path, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 6/8] qcow2: qcow2_co_preadv: improve locking,
Vladimir Sementsov-Ogievskiy <=
- [Qemu-devel] [PATCH v6 7/8] qcow2: bdrv_co_pwritev: move encryption code out of the lock, Vladimir Sementsov-Ogievskiy, 2019/05/06
- [Qemu-devel] [PATCH v6 1/8] qcow2.h: add missing include, Vladimir Sementsov-Ogievskiy, 2019/05/06
- Re: [Qemu-devel] [PATCH v6 0/8] qcow2: encryption threads, Max Reitz, 2019/05/09