Commit 063ab935 authored by NeilBrown's avatar NeilBrown Committed by Chuck Lever
Browse files

SUNRPC: integrate back-channel processing with svc_recv() 



Using svc_recv() 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: default avatarNeilBrown <neilb@suse.de>
Cc: Trond Myklebust <trond.myklebust@hammerspace.com>
Cc: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent 6ed8cdf9

fs/nfs/callback.c

+2 −40
Original line number Diff line number Diff line
@@ -78,7 +78,7 @@ nfs4_callback_svc(void *vrqstp) 


	set_freezable();



	while (!kthread_freezable_should_stop(NULL))

	while (!kthread_should_stop())

		svc_recv(rqstp);



	svc_exit_thread(rqstp);
@@ -86,41 +86,6 @@ 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;

	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);

			svc_process_bc(req, rqstp);

		} 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)

{
@@ -233,10 +198,7 @@ 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

include/linux/sunrpc/svc.h

+0 −2
Original line number Diff line number Diff line
@@ -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 */

};

net/sunrpc/backchannel_rqst.c

+3 −5
Original line number Diff line number Diff line
@@ -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->sv_pools[0]);

}

net/sunrpc/svc.c

+1 −1
Original line number Diff line number Diff line
@@ -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
@@ -718,6 +717,7 @@ void svc_pool_wake_idle_thread(struct svc_pool *pool) 


	set_bit(SP_CONGESTED, &pool->sp_flags);

}

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)

net/sunrpc/svc_xprt.c

+27 −0
Original line number Diff line number Diff line
@@ -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>
@@ -719,6 +720,13 @@ 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;

}
@@ -868,6 +876,25 @@ void svc_recv(struct svc_rqst *rqstp) 
		trace_svc_xprt_dequeue(rqstp);

		svc_handle_xprt(rqstp, xprt);

	}



#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);

			spin_unlock_bh(&serv->sv_cb_lock);



			svc_process_bc(req, rqstp);

			return;

		}

		spin_unlock_bh(&serv->sv_cb_lock);

	}

#endif

}

EXPORT_SYMBOL_GPL(svc_recv);