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[Qemu-devel] [PATCH 06/11] nbd: make it thread-safe
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PATCH 06/11] nbd: make it thread-safe |
Date: |
Wed, 31 May 2017 11:43:25 +0200 |
Signed-off-by: Paolo Bonzini <address@hidden>
---
block/nbd-client.c | 30 +++++++++---------------------
1 file changed, 9 insertions(+), 21 deletions(-)
diff --git a/block/nbd-client.c b/block/nbd-client.c
index 1e2952fdae..43e0292ac1 100644
--- a/block/nbd-client.c
+++ b/block/nbd-client.c
@@ -114,6 +114,10 @@ static int nbd_co_send_request(BlockDriverState *bs,
int rc, ret, i;
qemu_co_mutex_lock(&s->send_mutex);
+ while (s->in_flight == MAX_NBD_REQUESTS) {
+ qemu_co_queue_wait(&s->free_sema, &s->send_mutex);
+ }
+ s->in_flight++;
for (i = 0; i < MAX_NBD_REQUESTS; i++) {
if (s->recv_coroutine[i] == NULL) {
@@ -176,20 +180,6 @@ static void nbd_co_receive_reply(NBDClientSession *s,
}
}
-static void nbd_coroutine_start(NBDClientSession *s,
- NBDRequest *request)
-{
- /* Poor man semaphore. The free_sema is locked when no other request
- * can be accepted, and unlocked after receiving one reply. */
- if (s->in_flight == MAX_NBD_REQUESTS) {
- qemu_co_queue_wait(&s->free_sema, NULL);
- assert(s->in_flight < MAX_NBD_REQUESTS);
- }
- s->in_flight++;
-
- /* s->recv_coroutine[i] is set as soon as we get the send_lock. */
-}
-
static void nbd_coroutine_end(BlockDriverState *bs,
NBDRequest *request)
{
@@ -197,13 +187,16 @@ static void nbd_coroutine_end(BlockDriverState *bs,
int i = HANDLE_TO_INDEX(s, request->handle);
s->recv_coroutine[i] = NULL;
- s->in_flight--;
- qemu_co_queue_next(&s->free_sema);
/* Kick the read_reply_co to get the next reply. */
if (s->read_reply_co) {
aio_co_wake(s->read_reply_co);
}
+
+ qemu_co_mutex_lock(&s->send_mutex);
+ s->in_flight--;
+ qemu_co_queue_next(&s->free_sema);
+ qemu_co_mutex_unlock(&s->send_mutex);
}
int nbd_client_co_preadv(BlockDriverState *bs, uint64_t offset,
@@ -221,7 +214,6 @@ int nbd_client_co_preadv(BlockDriverState *bs, uint64_t
offset,
assert(bytes <= NBD_MAX_BUFFER_SIZE);
assert(!flags);
- nbd_coroutine_start(client, &request);
ret = nbd_co_send_request(bs, &request, NULL);
if (ret < 0) {
reply.error = -ret;
@@ -251,7 +243,6 @@ int nbd_client_co_pwritev(BlockDriverState *bs, uint64_t
offset,
assert(bytes <= NBD_MAX_BUFFER_SIZE);
- nbd_coroutine_start(client, &request);
ret = nbd_co_send_request(bs, &request, qiov);
if (ret < 0) {
reply.error = -ret;
@@ -286,7 +277,6 @@ int nbd_client_co_pwrite_zeroes(BlockDriverState *bs,
int64_t offset,
request.flags |= NBD_CMD_FLAG_NO_HOLE;
}
- nbd_coroutine_start(client, &request);
ret = nbd_co_send_request(bs, &request, NULL);
if (ret < 0) {
reply.error = -ret;
@@ -311,7 +301,6 @@ int nbd_client_co_flush(BlockDriverState *bs)
request.from = 0;
request.len = 0;
- nbd_coroutine_start(client, &request);
ret = nbd_co_send_request(bs, &request, NULL);
if (ret < 0) {
reply.error = -ret;
@@ -337,7 +326,6 @@ int nbd_client_co_pdiscard(BlockDriverState *bs, int64_t
offset, int count)
return 0;
}
- nbd_coroutine_start(client, &request);
ret = nbd_co_send_request(bs, &request, NULL);
if (ret < 0) {
reply.error = -ret;
--
2.13.0
- [Qemu-devel] [PATCH 05/11] vvfat: make it thread-safe, (continued)
- [Qemu-devel] [PATCH 05/11] vvfat: make it thread-safe, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 01/11] qcow2: call CoQueue APIs under CoMutex, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 02/11] coroutine-lock: add qemu_co_rwlock_downgrade and qemu_co_rwlock_upgrade, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 03/11] vdi: make it thread-safe, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 04/11] vpc: make it thread-safe, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 06/11] nbd: make it thread-safe,
Paolo Bonzini <=
- [Qemu-devel] [PATCH 07/11] qed: move tail of qed_aio_write_main to qed_aio_write_{cow, alloc}, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 08/11] block: invoke .bdrv_drain callback in coroutine context and from AioContext, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 11/11] ssh: support I/O from any AioContext, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 10/11] sheepdog: add queue_lock, Paolo Bonzini, 2017/05/31
- [Qemu-devel] [PATCH 09/11] qed: protect table cache with CoMutex, Paolo Bonzini, 2017/05/31