Commit 92f4433e authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

xprtrdma: Simplify locking that protects the rl_allreqs list 



Clean up: There's little chance of contention between the use of
rb_lock and rb_reqslock, so merge the two. This avoids having to
take both in some (possibly future) cases.

Transport tear-down is already serialized, thus there is no need for
locking at all when destroying rpcrdma_reqs.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 236b0943

net/sunrpc/xprtrdma/backchannel.c

+3 −17
Original line number Diff line number Diff line
@@ -19,29 +19,16 @@ 


#undef RPCRDMA_BACKCHANNEL_DEBUG



static void rpcrdma_bc_free_rqst(struct rpcrdma_xprt *r_xprt,

				 struct rpc_rqst *rqst)

{

	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;

	struct rpcrdma_req *req = rpcr_to_rdmar(rqst);



	spin_lock(&buf->rb_reqslock);

	list_del(&req->rl_all);

	spin_unlock(&buf->rb_reqslock);



	rpcrdma_destroy_req(req);

}



static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt,

				 unsigned int count)

{

	struct rpc_xprt *xprt = &r_xprt->rx_xprt;

	struct rpcrdma_req *req;

	struct rpc_rqst *rqst;

	unsigned int i;



	for (i = 0; i < (count << 1); i++) {

		struct rpcrdma_regbuf *rb;

		struct rpcrdma_req *req;

		size_t size;



		req = rpcrdma_create_req(r_xprt);
@@ -67,7 +54,7 @@ static int rpcrdma_bc_setup_reqs(struct rpcrdma_xprt *r_xprt, 
	return 0;



out_fail:

	rpcrdma_bc_free_rqst(r_xprt, rqst);

	rpcrdma_req_destroy(req);

	return -ENOMEM;

}
@@ -225,7 +212,6 @@ drop_connection: 
 */

void xprt_rdma_bc_destroy(struct rpc_xprt *xprt, unsigned int reqs)

{

	struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);

	struct rpc_rqst *rqst, *tmp;



	spin_lock(&xprt->bc_pa_lock);
@@ -233,7 +219,7 @@ void xprt_rdma_bc_destroy(struct rpc_xprt *xprt, unsigned int reqs) 
		list_del(&rqst->rq_bc_pa_list);

		spin_unlock(&xprt->bc_pa_lock);



		rpcrdma_bc_free_rqst(r_xprt, rqst);

		rpcrdma_req_destroy(rpcr_to_rdmar(rqst));



		spin_lock(&xprt->bc_pa_lock);

	}

net/sunrpc/xprtrdma/verbs.c

+17 −14
Original line number Diff line number Diff line
@@ -1043,9 +1043,9 @@ rpcrdma_create_req(struct rpcrdma_xprt *r_xprt) 
	req->rl_buffer = buffer;

	INIT_LIST_HEAD(&req->rl_registered);



	spin_lock(&buffer->rb_reqslock);

	spin_lock(&buffer->rb_lock);

	list_add(&req->rl_all, &buffer->rb_allreqs);

	spin_unlock(&buffer->rb_reqslock);

	spin_unlock(&buffer->rb_lock);

	return req;

}
@@ -1113,7 +1113,6 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) 


	INIT_LIST_HEAD(&buf->rb_send_bufs);

	INIT_LIST_HEAD(&buf->rb_allreqs);

	spin_lock_init(&buf->rb_reqslock);

	for (i = 0; i < buf->rb_max_requests; i++) {

		struct rpcrdma_req *req;
@@ -1154,9 +1153,18 @@ rpcrdma_destroy_rep(struct rpcrdma_rep *rep) 
	kfree(rep);

}



/**

 * rpcrdma_req_destroy - Destroy an rpcrdma_req object

 * @req: unused object to be destroyed

 *

 * This function assumes that the caller prevents concurrent device

 * unload and transport tear-down.

 */

void

rpcrdma_destroy_req(struct rpcrdma_req *req)

rpcrdma_req_destroy(struct rpcrdma_req *req)

{

	list_del(&req->rl_all);



	rpcrdma_free_regbuf(req->rl_recvbuf);

	rpcrdma_free_regbuf(req->rl_sendbuf);

	rpcrdma_free_regbuf(req->rl_rdmabuf);
@@ -1214,19 +1222,14 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf) 
		rpcrdma_destroy_rep(rep);

	}



	spin_lock(&buf->rb_reqslock);

	while (!list_empty(&buf->rb_allreqs)) {

	while (!list_empty(&buf->rb_send_bufs)) {

		struct rpcrdma_req *req;



		req = list_first_entry(&buf->rb_allreqs,

				       struct rpcrdma_req, rl_all);

		list_del(&req->rl_all);



		spin_unlock(&buf->rb_reqslock);

		rpcrdma_destroy_req(req);

		spin_lock(&buf->rb_reqslock);

		req = list_first_entry(&buf->rb_send_bufs,

				       struct rpcrdma_req, rl_list);

		list_del(&req->rl_list);

		rpcrdma_req_destroy(req);

	}

	spin_unlock(&buf->rb_reqslock);



	rpcrdma_mrs_destroy(buf);

}

net/sunrpc/xprtrdma/xprt_rdma.h

+3 −4
Original line number Diff line number Diff line
@@ -392,14 +392,13 @@ struct rpcrdma_buffer { 
	spinlock_t		rb_lock;	/* protect buf lists */

	struct list_head	rb_send_bufs;

	struct list_head	rb_recv_bufs;

	struct list_head	rb_allreqs;



	unsigned long		rb_flags;

	u32			rb_max_requests;

	u32			rb_credits;	/* most recent credit grant */



	u32			rb_bc_srv_max_requests;

	spinlock_t		rb_reqslock;	/* protect rb_allreqs */

	struct list_head	rb_allreqs;



	u32			rb_bc_max_requests;



	struct workqueue_struct *rb_completion_wq;
@@ -522,7 +521,7 @@ int rpcrdma_ep_post(struct rpcrdma_ia *, struct rpcrdma_ep *, 
 * Buffer calls - xprtrdma/verbs.c

 */

struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);

void rpcrdma_destroy_req(struct rpcrdma_req *);

void rpcrdma_req_destroy(struct rpcrdma_req *req);

int rpcrdma_buffer_create(struct rpcrdma_xprt *);

void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);

struct rpcrdma_sendctx *rpcrdma_sendctx_get_locked(struct rpcrdma_buffer *buf);

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