xprtrdma: Protect ia->ri_id when unmapping/invalidating MRs

Ensure ia->ri_id remains valid while invoking dma_unmap_page() or
posting LOCAL_INV during a transport reconnect. Otherwise,
ia->ri_id->device or ia->ri_id->qp is NULL, which triggers a panic.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=259
Fixes: ec62f40 'xprtrdma: Ensure ia->ri_id->qp is not NULL when reconnecting'
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Steve Wise <swise@opengridcomputing.com>
Tested-by: Shirley Ma <shirley.ma@oracle.com>
Tested-by: Devesh Sharma <devesh.sharma@emulex.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index f337bda..aa08de8 100644 (file)
--- a/net/sunrpc/xprtrdma/verbs.c
+++ b/net/sunrpc/xprtrdma/verbs.c
@@ -613,6 +613,7 @@ rpcrdma_ia_open(struct rpcrdma_xprt *xprt, struct sockaddr *addr, int memreg)
        /* Else will do memory reg/dereg for each chunk */
        ia->ri_memreg_strategy = memreg;
 
+       rwlock_init(&ia->ri_qplock);
        return 0;
 out2:
        rdma_destroy_id(ia->ri_id);
@@ -859,7 +860,7 @@ rpcrdma_ep_destroy(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 int
 rpcrdma_ep_connect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
 {
-       struct rdma_cm_id *id;
+       struct rdma_cm_id *id, *old;
        int rc = 0;
        int retry_count = 0;
 
@@ -905,9 +906,14 @@ retry:
                        rc = -ENETUNREACH;
                        goto out;
                }
-               rdma_destroy_qp(ia->ri_id);
-               rdma_destroy_id(ia->ri_id);
+
+               write_lock(&ia->ri_qplock);
+               old = ia->ri_id;
                ia->ri_id = id;
+               write_unlock(&ia->ri_qplock);
+
+               rdma_destroy_qp(old);
+               rdma_destroy_id(old);
        } else {
                dprintk("RPC:       %s: connecting...\n", __func__);
                rc = rdma_create_qp(ia->ri_id, ia->ri_pd, &ep->rep_attr);
@@ -1590,9 +1596,6 @@ rpcrdma_deregister_frmr_external(struct rpcrdma_mr_seg *seg,
        struct ib_send_wr invalidate_wr, *bad_wr;
        int rc;
 
-       while (seg1->mr_nsegs--)
-               rpcrdma_unmap_one(ia, seg++);
-
        memset(&invalidate_wr, 0, sizeof invalidate_wr);
        invalidate_wr.wr_id = (unsigned long)(void *)seg1->mr_chunk.rl_mw;
        invalidate_wr.opcode = IB_WR_LOCAL_INV;
@@ -1600,7 +1603,11 @@ rpcrdma_deregister_frmr_external(struct rpcrdma_mr_seg *seg,
        invalidate_wr.ex.invalidate_rkey = seg1->mr_chunk.rl_mw->r.frmr.fr_mr->rkey;
        DECR_CQCOUNT(&r_xprt->rx_ep);
 
+       read_lock(&ia->ri_qplock);
+       while (seg1->mr_nsegs--)
+               rpcrdma_unmap_one(ia, seg++);
        rc = ib_post_send(ia->ri_id->qp, &invalidate_wr, &bad_wr);
+       read_unlock(&ia->ri_qplock);
        if (rc)
                dprintk("RPC:       %s: failed ib_post_send for invalidate,"
                        " status %i\n", __func__, rc);
@@ -1661,8 +1668,10 @@ rpcrdma_deregister_fmr_external(struct rpcrdma_mr_seg *seg,
 
        list_add(&seg1->mr_chunk.rl_mw->r.fmr->list, &l);
        rc = ib_unmap_fmr(&l);
+       read_lock(&ia->ri_qplock);
        while (seg1->mr_nsegs--)
                rpcrdma_unmap_one(ia, seg++);
+       read_unlock(&ia->ri_qplock);
        if (rc)
                dprintk("RPC:       %s: failed ib_unmap_fmr,"
                        " status %i\n", __func__, rc);
@@ -1718,7 +1727,9 @@ rpcrdma_deregister_external(struct rpcrdma_mr_seg *seg,
 
 #if RPCRDMA_PERSISTENT_REGISTRATION
        case RPCRDMA_ALLPHYSICAL:
+               read_lock(&ia->ri_qplock);
                rpcrdma_unmap_one(ia, seg);
+               read_unlock(&ia->ri_qplock);
                break;
 #endif
 

diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 89e7cd4..97ca516 100644 (file)
--- a/net/sunrpc/xprtrdma/xprt_rdma.h
+++ b/net/sunrpc/xprtrdma/xprt_rdma.h
@@ -59,6 +59,7 @@
  * Interface Adapter -- one per transport instance
  */
 struct rpcrdma_ia {
+       rwlock_t                ri_qplock;
        struct rdma_cm_id       *ri_id;
        struct ib_pd            *ri_pd;
        struct ib_mr            *ri_bind_mem;