Commit eaf86e8c authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust
Browse files

xprtrdma: Improve locking around rpcrdma_rep destruction 



Currently rpcrdma_reps_destroy() assumes that, at transport
tear-down, the content of the rb_free_reps list is the same as the
content of the rb_all_reps list. Although that is usually true,
using the rb_all_reps list should be more reliable because of
the way it's managed. And, rpcrdma_reps_unmap() uses rb_all_reps;
these two functions should both traverse the "all" list.

Ensure that all rpcrdma_reps are always destroyed whether they are
on the rep free list or not.

Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent 5030c9a9

net/sunrpc/xprtrdma/verbs.c

+24 −7
Original line number Diff line number Diff line
@@ -1007,16 +1007,23 @@ struct rpcrdma_rep *rpcrdma_rep_create(struct rpcrdma_xprt *r_xprt, 
	return NULL;

}



/* No locking needed here. This function is invoked only by the

 * Receive completion handler, or during transport shutdown.

 */

static void rpcrdma_rep_destroy(struct rpcrdma_rep *rep)

static void rpcrdma_rep_free(struct rpcrdma_rep *rep)

{

	list_del(&rep->rr_all);

	rpcrdma_regbuf_free(rep->rr_rdmabuf);

	kfree(rep);

}



static void rpcrdma_rep_destroy(struct rpcrdma_rep *rep)

{

	struct rpcrdma_buffer *buf = &rep->rr_rxprt->rx_buf;



	spin_lock(&buf->rb_lock);

	list_del(&rep->rr_all);

	spin_unlock(&buf->rb_lock);



	rpcrdma_rep_free(rep);

}



static struct rpcrdma_rep *rpcrdma_rep_get_locked(struct rpcrdma_buffer *buf)

{

	struct llist_node *node;
@@ -1049,8 +1056,18 @@ static void rpcrdma_reps_destroy(struct rpcrdma_buffer *buf) 
{

	struct rpcrdma_rep *rep;



	while ((rep = rpcrdma_rep_get_locked(buf)) != NULL)

		rpcrdma_rep_destroy(rep);

	spin_lock(&buf->rb_lock);

	while ((rep = list_first_entry_or_null(&buf->rb_all_reps,

					       struct rpcrdma_rep,

					       rr_all)) != NULL) {

		list_del(&rep->rr_all);

		spin_unlock(&buf->rb_lock);



		rpcrdma_rep_free(rep);



		spin_lock(&buf->rb_lock);

	}

	spin_unlock(&buf->rb_lock);

}



/**