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authorTrond Myklebust <Trond.Myklebust@netapp.com>2011-07-17 16:01:03 -0400
committerTrond Myklebust <Trond.Myklebust@netapp.com>2011-07-17 16:01:03 -0400
commit43cedbf0e8dfb9c5610eb7985d5f21263e313802 (patch)
tree7758630292b6a276a3db72e63803ddc02c0a4444 /net/sunrpc
parentf85ef69ce08bc2209858135328335f668ba35bdb (diff)
SUNRPC: Ensure that we grab the XPRT_LOCK before calling xprt_alloc_slot
This throttles the allocation of new slots when the socket is busy reconnecting and/or is out of buffer space. Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Diffstat (limited to 'net/sunrpc')
-rw-r--r--net/sunrpc/xprt.c66
-rw-r--r--net/sunrpc/xprtrdma/transport.c5
-rw-r--r--net/sunrpc/xprtsock.c2
3 files changed, 46 insertions, 27 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index fbdbaf2cd58..ccd583a46ff 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -191,10 +191,9 @@ EXPORT_SYMBOL_GPL(xprt_load_transport);
* transport connects from colliding with writes. No congestion control
* is provided.
*/
-int xprt_reserve_xprt(struct rpc_task *task)
+int xprt_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
{
struct rpc_rqst *req = task->tk_rqstp;
- struct rpc_xprt *xprt = req->rq_xprt;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
if (task == xprt->snd_task)
@@ -202,8 +201,10 @@ int xprt_reserve_xprt(struct rpc_task *task)
goto out_sleep;
}
xprt->snd_task = task;
- req->rq_bytes_sent = 0;
- req->rq_ntrans++;
+ if (req != NULL) {
+ req->rq_bytes_sent = 0;
+ req->rq_ntrans++;
+ }
return 1;
@@ -212,7 +213,7 @@ out_sleep:
task->tk_pid, xprt);
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
- if (req->rq_ntrans)
+ if (req != NULL && req->rq_ntrans)
rpc_sleep_on(&xprt->resend, task, NULL);
else
rpc_sleep_on(&xprt->sending, task, NULL);
@@ -239,9 +240,8 @@ static void xprt_clear_locked(struct rpc_xprt *xprt)
* integrated into the decision of whether a request is allowed to be
* woken up and given access to the transport.
*/
-int xprt_reserve_xprt_cong(struct rpc_task *task)
+int xprt_reserve_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task)
{
- struct rpc_xprt *xprt = task->tk_xprt;
struct rpc_rqst *req = task->tk_rqstp;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state)) {
@@ -249,12 +249,14 @@ int xprt_reserve_xprt_cong(struct rpc_task *task)
return 1;
goto out_sleep;
}
+ if (req == NULL) {
+ xprt->snd_task = task;
+ return 1;
+ }
if (__xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
- if (req) {
- req->rq_bytes_sent = 0;
- req->rq_ntrans++;
- }
+ req->rq_bytes_sent = 0;
+ req->rq_ntrans++;
return 1;
}
xprt_clear_locked(xprt);
@@ -262,7 +264,7 @@ out_sleep:
dprintk("RPC: %5u failed to lock transport %p\n", task->tk_pid, xprt);
task->tk_timeout = 0;
task->tk_status = -EAGAIN;
- if (req && req->rq_ntrans)
+ if (req != NULL && req->rq_ntrans)
rpc_sleep_on(&xprt->resend, task, NULL);
else
rpc_sleep_on(&xprt->sending, task, NULL);
@@ -275,7 +277,7 @@ static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
int retval;
spin_lock_bh(&xprt->transport_lock);
- retval = xprt->ops->reserve_xprt(task);
+ retval = xprt->ops->reserve_xprt(xprt, task);
spin_unlock_bh(&xprt->transport_lock);
return retval;
}
@@ -291,7 +293,7 @@ static void __xprt_lock_write_next(struct rpc_xprt *xprt)
task = rpc_wake_up_next(&xprt->resend);
if (!task) {
task = rpc_wake_up_next(&xprt->sending);
- if (!task)
+ if (task == NULL)
goto out_unlock;
}
@@ -310,6 +312,7 @@ out_unlock:
static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
{
struct rpc_task *task;
+ struct rpc_rqst *req;
if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
return;
@@ -318,16 +321,19 @@ static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
task = rpc_wake_up_next(&xprt->resend);
if (!task) {
task = rpc_wake_up_next(&xprt->sending);
- if (!task)
+ if (task == NULL)
goto out_unlock;
}
+
+ req = task->tk_rqstp;
+ if (req == NULL) {
+ xprt->snd_task = task;
+ return;
+ }
if (__xprt_get_cong(xprt, task)) {
- struct rpc_rqst *req = task->tk_rqstp;
xprt->snd_task = task;
- if (req) {
- req->rq_bytes_sent = 0;
- req->rq_ntrans++;
- }
+ req->rq_bytes_sent = 0;
+ req->rq_ntrans++;
return;
}
out_unlock:
@@ -852,7 +858,7 @@ int xprt_prepare_transmit(struct rpc_task *task)
err = req->rq_reply_bytes_recvd;
goto out_unlock;
}
- if (!xprt->ops->reserve_xprt(task))
+ if (!xprt->ops->reserve_xprt(xprt, task))
err = -EAGAIN;
out_unlock:
spin_unlock_bh(&xprt->transport_lock);
@@ -933,8 +939,6 @@ static void xprt_alloc_slot(struct rpc_task *task)
struct rpc_xprt *xprt = task->tk_xprt;
task->tk_status = 0;
- if (task->tk_rqstp)
- return;
if (!list_empty(&xprt->free)) {
struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
list_del_init(&req->rq_list);
@@ -944,7 +948,6 @@ static void xprt_alloc_slot(struct rpc_task *task)
}
dprintk("RPC: waiting for request slot\n");
task->tk_status = -EAGAIN;
- task->tk_timeout = 0;
rpc_sleep_on(&xprt->backlog, task, NULL);
}
@@ -1001,10 +1004,25 @@ void xprt_reserve(struct rpc_task *task)
{
struct rpc_xprt *xprt = task->tk_xprt;
+ task->tk_status = 0;
+ if (task->tk_rqstp != NULL)
+ return;
+
+ /* Note: grabbing the xprt_lock_write() here is not strictly needed,
+ * but ensures that we throttle new slot allocation if the transport
+ * is congested (e.g. if reconnecting or if we're out of socket
+ * write buffer space).
+ */
+ task->tk_timeout = 0;
+ task->tk_status = -EAGAIN;
+ if (!xprt_lock_write(xprt, task))
+ return;
+
task->tk_status = -EIO;
spin_lock(&xprt->reserve_lock);
xprt_alloc_slot(task);
spin_unlock(&xprt->reserve_lock);
+ xprt_release_write(xprt, task);
}
static inline __be32 xprt_alloc_xid(struct rpc_xprt *xprt)
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 0867070bb5c..674a4922445 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -452,9 +452,8 @@ xprt_rdma_connect(struct rpc_task *task)
}
static int
-xprt_rdma_reserve_xprt(struct rpc_task *task)
+xprt_rdma_reserve_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
{
- struct rpc_xprt *xprt = task->tk_xprt;
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
int credits = atomic_read(&r_xprt->rx_buf.rb_credits);
@@ -466,7 +465,7 @@ xprt_rdma_reserve_xprt(struct rpc_task *task)
BUG_ON(r_xprt->rx_buf.rb_cwndscale <= 0);
}
xprt->cwnd = credits * r_xprt->rx_buf.rb_cwndscale;
- return xprt_reserve_xprt_cong(task);
+ return xprt_reserve_xprt_cong(xprt, task);
}
/*
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index cd6c410fa8f..adaa54c6a09 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -755,6 +755,8 @@ static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
if (task == NULL)
goto out_release;
req = task->tk_rqstp;
+ if (req == NULL)
+ goto out_release;
if (req->rq_bytes_sent == 0)
goto out_release;
if (req->rq_bytes_sent == req->rq_snd_buf.len)