Using svc_recv() and svc_process() for (NFSv4.1) back-channel handling
means we have just one mechanism for waking threads.
Also change kthread_freezable_should_stop() in nfs4_callback_svc() to
kthread_should_stop() as used elsewhere.
kthread_freezable_should_stop() effectively adds a try_to_freeze() call,
and svc_recv() already contains that at an appropriate place.
Signed-off-by: NeilBrown <neilb@xxxxxxx>
---
fs/nfs/callback.c | 46 ++---------------------------------
include/linux/sunrpc/svc.h | 6 +++--
net/sunrpc/backchannel_rqst.c | 8 ++----
net/sunrpc/svc.c | 2 +-
net/sunrpc/svc_xprt.c | 48 ++++++++++++++++++++++++++++++++++++-
net/sunrpc/xprtrdma/backchannel.c | 2 +-
6 files changed, 58 insertions(+), 54 deletions(-)
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index c47834970224..660cec36c45c 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -78,7 +78,7 @@ nfs4_callback_svc(void *vrqstp)
set_freezable();
- while (!kthread_freezable_should_stop(NULL)) {
+ while (!kthread_should_stop()) {
/*
* Listen for a request on the socket
*/
@@ -90,45 +90,6 @@ nfs4_callback_svc(void *vrqstp)
}
#if defined(CONFIG_NFS_V4_1)
-/*
- * The callback service for NFSv4.1 callbacks
- */
-static int
-nfs41_callback_svc(void *vrqstp)
-{
- struct svc_rqst *rqstp = vrqstp;
- struct svc_serv *serv = rqstp->rq_server;
- struct rpc_rqst *req;
- int error;
- DEFINE_WAIT(wq);
-
- set_freezable();
-
- while (!kthread_freezable_should_stop(NULL)) {
- prepare_to_wait(&serv->sv_cb_waitq, &wq, TASK_IDLE);
- spin_lock_bh(&serv->sv_cb_lock);
- if (!list_empty(&serv->sv_cb_list)) {
- req = list_first_entry(&serv->sv_cb_list,
- struct rpc_rqst, rq_bc_list);
- list_del(&req->rq_bc_list);
- spin_unlock_bh(&serv->sv_cb_lock);
- finish_wait(&serv->sv_cb_waitq, &wq);
- dprintk("Invoking bc_svc_process()\n");
- error = bc_svc_process(serv, req, rqstp);
- dprintk("bc_svc_process() returned w/ error code= %d\n",
- error);
- } else {
- spin_unlock_bh(&serv->sv_cb_lock);
- if (!kthread_should_stop())
- schedule();
- finish_wait(&serv->sv_cb_waitq, &wq);
- }
- }
-
- svc_exit_thread(rqstp);
- return 0;
-}
-
static inline void nfs_callback_bc_serv(u32 minorversion, struct rpc_xprt *xprt,
struct svc_serv *serv)
{
@@ -241,10 +202,7 @@ static struct svc_serv *nfs_callback_create_svc(int minorversion)
cb_info->users);
threadfn = nfs4_callback_svc;
-#if defined(CONFIG_NFS_V4_1)
- if (minorversion)
- threadfn = nfs41_callback_svc;
-#else
+#if !defined(CONFIG_NFS_V4_1)
if (minorversion)
return ERR_PTR(-ENOTSUPP);
#endif
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 83f31a09c853..15d468d852b5 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -92,8 +92,6 @@ struct svc_serv {
* that arrive over the same
* connection */
spinlock_t sv_cb_lock; /* protects the svc_cb_list */
- wait_queue_head_t sv_cb_waitq; /* sleep here if there are no
- * entries in the svc_cb_list */
bool sv_bc_enabled; /* service uses backchannel */
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
};
@@ -202,6 +200,10 @@ struct svc_rqst {
struct rcu_head rq_rcu_head; /* for RCU deferred kfree */
struct svc_xprt * rq_xprt; /* transport ptr */
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+ struct rpc_rqst *rq_cb; /* callback to be handled */
+#endif
+
struct sockaddr_storage rq_addr; /* peer address */
size_t rq_addrlen;
struct sockaddr_storage rq_daddr; /* dest addr of request
diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c
index 65a6c6429a53..60b8d310bb27 100644
--- a/net/sunrpc/backchannel_rqst.c
+++ b/net/sunrpc/backchannel_rqst.c
@@ -349,10 +349,8 @@ struct rpc_rqst *xprt_lookup_bc_request(struct rpc_xprt *xprt, __be32 xid)
}
/*
- * Add callback request to callback list. The callback
- * service sleeps on the sv_cb_waitq waiting for new
- * requests. Wake it up after adding enqueing the
- * request.
+ * Add callback request to callback list. Wake a thread
+ * on the first pool (usually the only pool) to handle it.
*/
void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
{
@@ -371,6 +369,6 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied)
xprt_get(xprt);
spin_lock(&bc_serv->sv_cb_lock);
list_add(&req->rq_bc_list, &bc_serv->sv_cb_list);
- wake_up(&bc_serv->sv_cb_waitq);
spin_unlock(&bc_serv->sv_cb_lock);
+ svc_pool_wake_idle_thread(bc_serv, &bc_serv->sv_pools[0]);
}
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 170eabc03988..56b4a88776d5 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -440,7 +440,6 @@ __svc_init_bc(struct svc_serv *serv)
{
INIT_LIST_HEAD(&serv->sv_cb_list);
spin_lock_init(&serv->sv_cb_lock);
- init_waitqueue_head(&serv->sv_cb_waitq);
}
#else
static void
@@ -724,6 +723,7 @@ struct svc_rqst *svc_pool_wake_idle_thread(struct svc_serv *serv,
percpu_counter_inc(&pool->sp_threads_starved);
return NULL;
}
+EXPORT_SYMBOL_GPL(svc_pool_wake_idle_thread);
static struct svc_pool *
svc_pool_next(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index c7095ff7d5fd..4fdf1aaa514b 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -17,6 +17,7 @@
#include <linux/sunrpc/svc_xprt.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/xprt.h>
+#include <linux/sunrpc/bc_xprt.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <trace/events/sunrpc.h>
@@ -732,6 +733,13 @@ rqst_should_sleep(struct svc_rqst *rqstp)
if (freezing(current))
return false;
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+ if (svc_is_backchannel(rqstp)) {
+ if (!list_empty(&rqstp->rq_server->sv_cb_list))
+ return false;
+ }
+#endif
+
return true;
}
@@ -754,12 +762,31 @@ static void svc_wait_for_work(struct svc_rqst *rqstp)
set_bit(RQ_BUSY, &rqstp->rq_flags);
smp_mb__after_atomic();
+
rqstp->rq_xprt = svc_xprt_dequeue(pool);
if (rqstp->rq_xprt) {
trace_svc_pool_awoken(rqstp);
goto out_found;
}
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+ if (svc_is_backchannel(rqstp)) {
+ struct svc_serv *serv = rqstp->rq_server;
+ struct rpc_rqst *req;
+
+ spin_lock_bh(&serv->sv_cb_lock);
+ req = list_first_entry_or_null(&serv->sv_cb_list,
+ struct rpc_rqst, rq_bc_list);
+ if (req) {
+ list_del(&req->rq_bc_list);
+ rqstp->rq_cb = req;
+ }
+ spin_unlock_bh(&serv->sv_cb_lock);
+ if (rqstp->rq_cb)
+ goto out_found;
+ }
+#endif
+
if (!kthread_should_stop())
percpu_counter_inc(&pool->sp_threads_no_work);
return;
@@ -853,7 +880,7 @@ void svc_recv(struct svc_rqst *rqstp)
svc_wait_for_work(rqstp);
if (rqstp->rq_xprt) {
- struct svc_serv *serv = rqstp->rq_server;
+ struct svc_serv *serv = rqstp->rq_server;
struct svc_xprt *xprt = rqstp->rq_xprt;
int len;
@@ -878,6 +905,25 @@ void svc_recv(struct svc_rqst *rqstp)
svc_process(rqstp);
}
}
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+ if (svc_is_backchannel(rqstp)) {
+ struct rpc_rqst *cb;
+ int error;
+
+ if (!rqstp->rq_cb)
+ return;
+
+ cb = rqstp->rq_cb;
+ rqstp->rq_cb = NULL;
+
+ dprintk("Invoking bc_svc_process()\n");
+ error = bc_svc_process(rqstp->rq_server, cb, rqstp);
+ dprintk("bc_svc_process() returned w/ error code= %d\n",
+ error);
+ return;
+ }
+#endif
+
}
EXPORT_SYMBOL_GPL(svc_recv);
diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index e4d84a13c566..f1e1d4909434 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -267,7 +267,7 @@ void rpcrdma_bc_receive_call(struct rpcrdma_xprt *r_xprt,
list_add(&rqst->rq_bc_list, &bc_serv->sv_cb_list);
spin_unlock(&bc_serv->sv_cb_lock);
- wake_up(&bc_serv->sv_cb_waitq);
+ svc_pool_wake_idle_thread(bc_serv, &bc_serv->sv_pools[0]);
r_xprt->rx_stats.bcall_count++;
return;
