We have to ensure that the wake up from the waitqueue and the assignment
of xprt->snd_task are atomic. We can do this by assigning the snd_task
while under the waitqueue spinlock.
Signed-off-by: Trond Myklebust <Trond.Myklebust@xxxxxxxxxx>
---
fs/nfs/nfs4_fs.h | 1 +
fs/nfs/nfs4proc.c | 13 ++++++----
fs/nfs/nfs4state.c | 17 ++++++-------
include/linux/sunrpc/sched.h | 3 ++
net/sunrpc/sched.c | 42 ++++++++++++++++++++++++++++-------
net/sunrpc/xprt.c | 49 ++++++++++++++++++++++-------------------
6 files changed, 79 insertions(+), 46 deletions(-)
diff --git a/fs/nfs/nfs4_fs.h b/fs/nfs/nfs4_fs.h
index b7e5a1d..fbb1bc0 100644
--- a/fs/nfs/nfs4_fs.h
+++ b/fs/nfs/nfs4_fs.h
@@ -222,6 +222,7 @@ static inline struct nfs4_session *nfs4_get_session(const struct nfs_server *ser
return server->nfs_client->cl_session;
}
+extern bool nfs4_set_task_privileged(struct rpc_task *task, void *dummy);
extern int nfs4_setup_sequence(const struct nfs_server *server,
struct nfs4_sequence_args *args, struct nfs4_sequence_res *res,
struct rpc_task *task);
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f2a4d32..734bd5a 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -385,17 +385,20 @@ nfs4_free_slot(struct nfs4_slot_table *tbl, u8 free_slotid)
free_slotid, tbl->highest_used_slotid);
}
+bool nfs4_set_task_privileged(struct rpc_task *task, void *dummy)
+{
+ rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
+ return true;
+}
+
/*
* Signal state manager thread if session fore channel is drained
*/
static void nfs4_check_drain_fc_complete(struct nfs4_session *ses)
{
- struct rpc_task *task;
-
if (!test_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
- task = rpc_wake_up_next(&ses->fc_slot_table.slot_tbl_waitq);
- if (task)
- rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
+ rpc_wake_up_first(&ses->fc_slot_table.slot_tbl_waitq,
+ nfs4_set_task_privileged, NULL);
return;
}
diff --git a/fs/nfs/nfs4state.c b/fs/nfs/nfs4state.c
index a42e60d..f0e9881 100644
--- a/fs/nfs/nfs4state.c
+++ b/fs/nfs/nfs4state.c
@@ -190,23 +190,22 @@ static int nfs41_setup_state_renewal(struct nfs_client *clp)
static void nfs4_end_drain_session(struct nfs_client *clp)
{
struct nfs4_session *ses = clp->cl_session;
+ struct nfs4_slot_table *tbl;
int max_slots;
if (ses == NULL)
return;
+ tbl = &ses->fc_slot_table;
if (test_and_clear_bit(NFS4_SESSION_DRAINING, &ses->session_state)) {
- spin_lock(&ses->fc_slot_table.slot_tbl_lock);
- max_slots = ses->fc_slot_table.max_slots;
+ spin_lock(&tbl->slot_tbl_lock);
+ max_slots = tbl->max_slots;
while (max_slots--) {
- struct rpc_task *task;
-
- task = rpc_wake_up_next(&ses->fc_slot_table.
- slot_tbl_waitq);
- if (!task)
+ if (rpc_wake_up_first(&tbl->slot_tbl_waitq,
+ nfs4_set_task_privileged,
+ NULL) == NULL)
break;
- rpc_task_set_priority(task, RPC_PRIORITY_PRIVILEGED);
}
- spin_unlock(&ses->fc_slot_table.slot_tbl_lock);
+ spin_unlock(&tbl->slot_tbl_lock);
}
}
diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
index b16243a..bd337f9 100644
--- a/include/linux/sunrpc/sched.h
+++ b/include/linux/sunrpc/sched.h
@@ -235,6 +235,9 @@ void rpc_wake_up_queued_task(struct rpc_wait_queue *,
struct rpc_task *);
void rpc_wake_up(struct rpc_wait_queue *);
struct rpc_task *rpc_wake_up_next(struct rpc_wait_queue *);
+struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *,
+ bool (*)(struct rpc_task *, void *),
+ void *);
void rpc_wake_up_status(struct rpc_wait_queue *, int);
int rpc_queue_empty(struct rpc_wait_queue *);
void rpc_delay(struct rpc_task *, unsigned long);
diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 3341d89..7c8142e 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -422,7 +422,7 @@ EXPORT_SYMBOL_GPL(rpc_wake_up_queued_task);
/*
* Wake up the next task on a priority queue.
*/
-static struct rpc_task * __rpc_wake_up_next_priority(struct rpc_wait_queue *queue)
+static struct rpc_task *__rpc_find_next_queued_priority(struct rpc_wait_queue *queue)
{
struct list_head *q;
struct rpc_task *task;
@@ -467,30 +467,54 @@ new_queue:
new_owner:
rpc_set_waitqueue_owner(queue, task->tk_owner);
out:
- rpc_wake_up_task_queue_locked(queue, task);
return task;
}
+static struct rpc_task *__rpc_find_next_queued(struct rpc_wait_queue *queue)
+{
+ if (RPC_IS_PRIORITY(queue))
+ return __rpc_find_next_queued_priority(queue);
+ if (!list_empty(&queue->tasks[0]))
+ return list_first_entry(&queue->tasks[0], struct rpc_task, u.tk_wait.list);
+ return NULL;
+}
+
/*
- * Wake up the next task on the wait queue.
+ * Wake up the first task on the wait queue.
*/
-struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
+struct rpc_task *rpc_wake_up_first(struct rpc_wait_queue *queue,
+ bool (*func)(struct rpc_task *, void *), void *data)
{
struct rpc_task *task = NULL;
- dprintk("RPC: wake_up_next(%p \"%s\")\n",
+ dprintk("RPC: wake_up_first(%p \"%s\")\n",
queue, rpc_qname(queue));
spin_lock_bh(&queue->lock);
- if (RPC_IS_PRIORITY(queue))
- task = __rpc_wake_up_next_priority(queue);
- else {
- task_for_first(task, &queue->tasks[0])
+ task = __rpc_find_next_queued(queue);
+ if (task != NULL) {
+ if (func(task, data))
rpc_wake_up_task_queue_locked(queue, task);
+ else
+ task = NULL;
}
spin_unlock_bh(&queue->lock);
return task;
}
+EXPORT_SYMBOL_GPL(rpc_wake_up_first);
+
+static bool rpc_wake_up_next_func(struct rpc_task *task, void *data)
+{
+ return true;
+}
+
+/*
+ * Wake up the next task on the wait queue.
+*/
+struct rpc_task * rpc_wake_up_next(struct rpc_wait_queue *queue)
+{
+ return rpc_wake_up_first(queue, rpc_wake_up_next_func, NULL);
+}
EXPORT_SYMBOL_GPL(rpc_wake_up_next);
/**
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index c64c0ef..839f6ef 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -292,54 +292,57 @@ static inline int xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
return retval;
}
-static void __xprt_lock_write_next(struct rpc_xprt *xprt)
+static bool __xprt_lock_write_func(struct rpc_task *task, void *data)
{
- struct rpc_task *task;
+ struct rpc_xprt *xprt = data;
struct rpc_rqst *req;
- if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
- return;
-
- task = rpc_wake_up_next(&xprt->sending);
- if (task == NULL)
- goto out_unlock;
-
req = task->tk_rqstp;
xprt->snd_task = task;
if (req) {
req->rq_bytes_sent = 0;
req->rq_ntrans++;
}
- return;
+ return true;
+}
-out_unlock:
+static void __xprt_lock_write_next(struct rpc_xprt *xprt)
+{
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
+ return;
+
+ if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_func, xprt))
+ return;
xprt_clear_locked(xprt);
}
-static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
+static bool __xprt_lock_write_cong_func(struct rpc_task *task, void *data)
{
- struct rpc_task *task;
+ struct rpc_xprt *xprt = data;
struct rpc_rqst *req;
- if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
- return;
- if (RPCXPRT_CONGESTED(xprt))
- goto out_unlock;
- task = rpc_wake_up_next(&xprt->sending);
- if (task == NULL)
- goto out_unlock;
-
req = task->tk_rqstp;
if (req == NULL) {
xprt->snd_task = task;
- return;
+ return true;
}
if (__xprt_get_cong(xprt, task)) {
xprt->snd_task = task;
req->rq_bytes_sent = 0;
req->rq_ntrans++;
- return;
+ return true;
}
+ return false;
+}
+
+static void __xprt_lock_write_next_cong(struct rpc_xprt *xprt)
+{
+ if (test_and_set_bit(XPRT_LOCKED, &xprt->state))
+ return;
+ if (RPCXPRT_CONGESTED(xprt))
+ goto out_unlock;
+ if (rpc_wake_up_first(&xprt->sending, __xprt_lock_write_cong_func, xprt))
+ return;
out_unlock:
xprt_clear_locked(xprt);
}
--
1.7.7.5
--
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