Commit d698c4a0 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
Browse files

xprtrdma: Fix backchannel allocation of extra rpcrdma_reps 



The backchannel code uses rpcrdma_recv_buffer_put to add new reps
to the free rep list. This also decrements rb_recv_count, which
spoofs the receive overrun logic in rpcrdma_buffer_get_rep.

Commit 9b06688b ("xprtrdma: Fix additional uses of
spin_lock_irqsave(rb_lock)") replaced the original open-coded
list_add with a call to rpcrdma_recv_buffer_put(), but then a year
later, commit 05c97466 ("xprtrdma: Fix receive buffer
accounting") added rep accounting to rpcrdma_recv_buffer_put.
It was an oversight to let the backchannel continue to use this
function.

The fix this, let's combine the "add to free list" logic with
rpcrdma_create_rep.

Also, do not allocate RPCRDMA_MAX_BC_REQUESTS rpcrdma_reps in
rpcrdma_buffer_create and then allocate additional rpcrdma_reps in
rpcrdma_bc_setup_reps. Allocating the extra reps during backchannel
set-up is sufficient.

Fixes: 05c97466 ("xprtrdma: Fix receive buffer accounting")
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 03ac1a76

net/sunrpc/xprtrdma/backchannel.c

+2 −10
Original line number Diff line number Diff line
@@ -74,21 +74,13 @@ out_fail: 
static int rpcrdma_bc_setup_reps(struct rpcrdma_xprt *r_xprt,

				 unsigned int count)

{

	struct rpcrdma_rep *rep;

	int rc = 0;



	while (count--) {

		rep = rpcrdma_create_rep(r_xprt);

		if (IS_ERR(rep)) {

			pr_err("RPC:       %s: reply buffer alloc failed\n",

			       __func__);

			rc = PTR_ERR(rep);

		rc = rpcrdma_create_rep(r_xprt);

		if (rc)

			break;

	}



		rpcrdma_recv_buffer_put(rep);

	}



	return rc;

}

net/sunrpc/xprtrdma/verbs.c

+19 −13
Original line number Diff line number Diff line
@@ -1093,10 +1093,17 @@ rpcrdma_create_req(struct rpcrdma_xprt *r_xprt) 
	return req;

}



struct rpcrdma_rep *

/**

 * rpcrdma_create_rep - Allocate an rpcrdma_rep object

 * @r_xprt: controlling transport

 *

 * Returns 0 on success or a negative errno on failure.

 */

int

rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)

{

	struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;

	struct rpcrdma_buffer *buf = &r_xprt->rx_buf;

	struct rpcrdma_rep *rep;

	int rc;
@@ -1121,12 +1128,18 @@ rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt) 
	rep->rr_recv_wr.wr_cqe = &rep->rr_cqe;

	rep->rr_recv_wr.sg_list = &rep->rr_rdmabuf->rg_iov;

	rep->rr_recv_wr.num_sge = 1;

	return rep;



	spin_lock(&buf->rb_lock);

	list_add(&rep->rr_list, &buf->rb_recv_bufs);

	spin_unlock(&buf->rb_lock);

	return 0;



out_free:

	kfree(rep);

out:

	return ERR_PTR(rc);

	dprintk("RPC:       %s: reply buffer %d alloc failed\n",

		__func__, rc);

	return rc;

}



int
@@ -1167,18 +1180,11 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt) 
	}



	INIT_LIST_HEAD(&buf->rb_recv_bufs);

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

		struct rpcrdma_rep *rep;



		rep = rpcrdma_create_rep(r_xprt);

		if (IS_ERR(rep)) {

			dprintk("RPC:       %s: reply buffer %d alloc failed\n",

				__func__, i);

			rc = PTR_ERR(rep);

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

		rc = rpcrdma_create_rep(r_xprt);

		if (rc)

			goto out;

	}

		list_add(&rep->rr_list, &buf->rb_recv_bufs);

	}



	rc = rpcrdma_sendctxs_create(r_xprt);

	if (rc)

net/sunrpc/xprtrdma/xprt_rdma.h

+1 −1
Original line number Diff line number Diff line
@@ -564,8 +564,8 @@ int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_rep *); 
 * Buffer calls - xprtrdma/verbs.c

 */

struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);

struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);

void rpcrdma_destroy_req(struct rpcrdma_req *);

int rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt);

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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