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Commit c2922c02 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

xprtrdma: Properly handle exhaustion of the rb_mws list 



If the rb_mws list is exhausted, clean up and return NULL so that
call_allocate() will delay and try again.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Tested-by: default avatarSteve Wise <swise@opengridcomputing.com>
Tested-by: default avatarShirley Ma <shirley.ma@oracle.com>
Tested-by: default avatarDevesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 3111d72c

net/sunrpc/xprtrdma/verbs.c

+71 −32
Original line number Diff line number Diff line
@@ -1256,6 +1256,67 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf) 
	kfree(buf->rb_pool);

}



/* "*mw" can be NULL when rpcrdma_buffer_get_mrs() fails, leaving

 * some req segments uninitialized.

 */

static void

rpcrdma_buffer_put_mr(struct rpcrdma_mw **mw, struct rpcrdma_buffer *buf)

{

	if (*mw) {

		list_add_tail(&(*mw)->mw_list, &buf->rb_mws);

		*mw = NULL;

	}

}



/* Cycle mw's back in reverse order, and "spin" them.

 * This delays and scrambles reuse as much as possible.

 */

static void

rpcrdma_buffer_put_mrs(struct rpcrdma_req *req, struct rpcrdma_buffer *buf)

{

	struct rpcrdma_mr_seg *seg = req->rl_segments;

	struct rpcrdma_mr_seg *seg1 = seg;

	int i;



	for (i = 1, seg++; i < RPCRDMA_MAX_SEGS; seg++, i++)

		rpcrdma_buffer_put_mr(&seg->mr_chunk.rl_mw, buf);

	rpcrdma_buffer_put_mr(&seg1->mr_chunk.rl_mw, buf);

}



static void

rpcrdma_buffer_put_sendbuf(struct rpcrdma_req *req, struct rpcrdma_buffer *buf)

{

	buf->rb_send_bufs[--buf->rb_send_index] = req;

	req->rl_niovs = 0;

	if (req->rl_reply) {

		buf->rb_recv_bufs[--buf->rb_recv_index] = req->rl_reply;

		req->rl_reply->rr_func = NULL;

		req->rl_reply = NULL;

	}

}



static struct rpcrdma_req *

rpcrdma_buffer_get_mrs(struct rpcrdma_req *req, struct rpcrdma_buffer *buf)

{

	struct rpcrdma_mw *r;

	int i;



	i = RPCRDMA_MAX_SEGS - 1;

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

		r = list_entry(buf->rb_mws.next,

			       struct rpcrdma_mw, mw_list);

		list_del(&r->mw_list);

		req->rl_segments[i].mr_chunk.rl_mw = r;

		if (unlikely(i-- == 0))

			return req;	/* Success */

	}



	/* Not enough entries on rb_mws for this req */

	rpcrdma_buffer_put_sendbuf(req, buf);

	rpcrdma_buffer_put_mrs(req, buf);

	return NULL;

}



/*

 * Get a set of request/reply buffers.

 *
@@ -1268,10 +1329,9 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf) 
struct rpcrdma_req *

rpcrdma_buffer_get(struct rpcrdma_buffer *buffers)

{

	struct rpcrdma_ia *ia = rdmab_to_ia(buffers);

	struct rpcrdma_req *req;

	unsigned long flags;

	int i;

	struct rpcrdma_mw *r;



	spin_lock_irqsave(&buffers->rb_lock, flags);

	if (buffers->rb_send_index == buffers->rb_max_requests) {
@@ -1291,14 +1351,13 @@ rpcrdma_buffer_get(struct rpcrdma_buffer *buffers) 
		buffers->rb_recv_bufs[buffers->rb_recv_index++] = NULL;

	}

	buffers->rb_send_bufs[buffers->rb_send_index++] = NULL;

	if (!list_empty(&buffers->rb_mws)) {

		i = RPCRDMA_MAX_SEGS - 1;

		do {

			r = list_entry(buffers->rb_mws.next,

					struct rpcrdma_mw, mw_list);

			list_del(&r->mw_list);

			req->rl_segments[i].mr_chunk.rl_mw = r;

		} while (--i >= 0);

	switch (ia->ri_memreg_strategy) {

	case RPCRDMA_FRMR:

	case RPCRDMA_MTHCAFMR:

		req = rpcrdma_buffer_get_mrs(req, buffers);

		break;

	default:

		break;

	}

	spin_unlock_irqrestore(&buffers->rb_lock, flags);

	return req;
@@ -1313,34 +1372,14 @@ rpcrdma_buffer_put(struct rpcrdma_req *req) 
{

	struct rpcrdma_buffer *buffers = req->rl_buffer;

	struct rpcrdma_ia *ia = rdmab_to_ia(buffers);

	int i;

	unsigned long flags;



	spin_lock_irqsave(&buffers->rb_lock, flags);

	buffers->rb_send_bufs[--buffers->rb_send_index] = req;

	req->rl_niovs = 0;

	if (req->rl_reply) {

		buffers->rb_recv_bufs[--buffers->rb_recv_index] = req->rl_reply;

		req->rl_reply->rr_func = NULL;

		req->rl_reply = NULL;

	}

	rpcrdma_buffer_put_sendbuf(req, buffers);

	switch (ia->ri_memreg_strategy) {

	case RPCRDMA_FRMR:

	case RPCRDMA_MTHCAFMR:

		/*

		 * Cycle mw's back in reverse order, and "spin" them.

		 * This delays and scrambles reuse as much as possible.

		 */

		i = 1;

		do {

			struct rpcrdma_mw **mw;

			mw = &req->rl_segments[i].mr_chunk.rl_mw;

			list_add_tail(&(*mw)->mw_list, &buffers->rb_mws);

			*mw = NULL;

		} while (++i < RPCRDMA_MAX_SEGS);

		list_add_tail(&req->rl_segments[0].mr_chunk.rl_mw->mw_list,

					&buffers->rb_mws);

		req->rl_segments[0].mr_chunk.rl_mw = NULL;

		rpcrdma_buffer_put_mrs(req, buffers);

		break;

	default:

		break;