[PATCH v1 02/13] xprtrdma: Protect ->qp during FRMR deregistration

Chuck Lever
2014-06-23T22:39:17Z

Ensure the QP remains valid while posting LOCAL_INV during a
transport reconnect. Otherwise, ia->ri_id->qp is NULL, which
triggers a panic.

BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=259
Fixes: ec62f40d3505a643497d105c297093bb90afd44e
Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
net/sunrpc/xprtrdma/verbs.c | 14 +++++++++++---
net/sunrpc/xprtrdma/xprt_rdma.h | 1 +
2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c
index 78bd7c6..f70b8ad 100644
--- 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);
@@ -1597,7 +1603,9 @@ 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);
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);
diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h
index 89e7cd4..97ca516 100644
--- 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;

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