There are rare cases where an rpcrdma_req and its matched rpcrdma_rep can be re-used, via rpcrdma_buffer_put, while the RPC reply handler is still using that req. This is typically due to a signal firing at just the wrong instant. As part of closing this race window, avoid using the wrong rpcrdma_rep to detect remotely invalidated MRs. Mark MRs as invalidated while we are sure the rep is still OK to use. BugLink: https://bugzilla.linux-nfs.org/show_bug.cgi?id=305 Fixes: 68791649a725 ('xprtrdma: Invalidate in the RPC reply ... ') Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> --- net/sunrpc/xprtrdma/frwr_ops.c | 4 +--- net/sunrpc/xprtrdma/rpc_rdma.c | 22 ++++++++++++++++++++-- net/sunrpc/xprtrdma/verbs.c | 1 + net/sunrpc/xprtrdma/xprt_rdma.h | 6 ++++++ 4 files changed, 28 insertions(+), 5 deletions(-) diff --git a/net/sunrpc/xprtrdma/frwr_ops.c b/net/sunrpc/xprtrdma/frwr_ops.c index f81dd93..31290cb 100644 --- a/net/sunrpc/xprtrdma/frwr_ops.c +++ b/net/sunrpc/xprtrdma/frwr_ops.c @@ -464,7 +464,6 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req) { struct ib_send_wr *first, **prev, *last, *bad_wr; - struct rpcrdma_rep *rep = req->rl_reply; struct rpcrdma_ia *ia = &r_xprt->rx_ia; struct rpcrdma_frmr *f; struct rpcrdma_mw *mw; @@ -483,8 +482,7 @@ list_for_each_entry(mw, &req->rl_registered, mw_list) { mw->frmr.fr_state = FRMR_IS_INVALID; - if ((rep->rr_wc_flags & IB_WC_WITH_INVALIDATE) && - (mw->mw_handle == rep->rr_inv_rkey)) + if (mw->mw_flags & RPCRDMA_MW_F_RI) continue; f = &mw->frmr; diff --git a/net/sunrpc/xprtrdma/rpc_rdma.c b/net/sunrpc/xprtrdma/rpc_rdma.c index 694e9b1..2356a63 100644 --- a/net/sunrpc/xprtrdma/rpc_rdma.c +++ b/net/sunrpc/xprtrdma/rpc_rdma.c @@ -928,6 +928,24 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt, return fixup_copy_count; } +/* Caller must guarantee @rep remains stable during this call. + */ +static void +rpcrdma_mark_remote_invalidation(struct list_head *mws, + struct rpcrdma_rep *rep) +{ + struct rpcrdma_mw *mw; + + if (!(rep->rr_wc_flags & IB_WC_WITH_INVALIDATE)) + return; + + list_for_each_entry(mw, mws, mw_list) + if (mw->mw_handle == rep->rr_inv_rkey) { + mw->mw_flags = RPCRDMA_MW_F_RI; + break; /* only one invalidated MR per RPC */ + } +} + #if defined(CONFIG_SUNRPC_BACKCHANNEL) /* By convention, backchannel calls arrive via rdma_msg type * messages, and never populate the chunk lists. This makes @@ -1006,13 +1024,13 @@ static bool rpcrdma_results_inline(struct rpcrdma_xprt *r_xprt, /* Sanity checking has passed. We are now committed * to complete this transaction. */ + rpcrdma_mark_remote_invalidation(&req->rl_registered, rep); list_del_init(&rqst->rq_list); + req->rl_reply = rep; spin_unlock_bh(&xprt->transport_lock); dprintk("RPC: %s: reply %p completes request %p (xid 0x%08x)\n", __func__, rep, req, be32_to_cpu(headerp->rm_xid)); - /* from here on, the reply is no longer an orphan */ - req->rl_reply = rep; xprt->reestablish_timeout = 0; if (headerp->rm_vers != rpcrdma_version) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 3dbce9a..a8be66d 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1187,6 +1187,7 @@ struct rpcrdma_mw * if (!mw) goto out_nomws; + mw->mw_flags = 0; return mw; out_nomws: diff --git a/net/sunrpc/xprtrdma/xprt_rdma.h b/net/sunrpc/xprtrdma/xprt_rdma.h index 1d66acf..2e02733 100644 --- a/net/sunrpc/xprtrdma/xprt_rdma.h +++ b/net/sunrpc/xprtrdma/xprt_rdma.h @@ -271,6 +271,7 @@ struct rpcrdma_mw { struct scatterlist *mw_sg; int mw_nents; enum dma_data_direction mw_dir; + unsigned long mw_flags; union { struct rpcrdma_fmr fmr; struct rpcrdma_frmr frmr; @@ -282,6 +283,11 @@ struct rpcrdma_mw { struct list_head mw_all; }; +/* mw_flags */ +enum { + RPCRDMA_MW_F_RI = 1, +}; + /* * struct rpcrdma_req -- structure central to the request/reply sequence. * -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
