Commit 4b196dc6 authored by Chuck Lever's avatar Chuck Lever Committed by Anna Schumaker
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xprtrdma: Pre-mark remotely invalidated MRs

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: 68791649

 ('xprtrdma: Invalidate in the RPC reply ... ')
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 04d25b7d
......@@ -464,7 +464,6 @@ static void
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 @@ frwr_op_unmap_sync(struct rpcrdma_xprt *r_xprt, struct rpcrdma_req *req)
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;
......
......@@ -928,6 +928,24 @@ rpcrdma_inline_fixup(struct rpc_rqst *rqst, char *srcp, int copy_len, int pad)
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 @@ rpcrdma_reply_handler(struct work_struct *work)
/* 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)
......
......@@ -1187,6 +1187,7 @@ rpcrdma_get_mw(struct rpcrdma_xprt *r_xprt)
if (!mw)
goto out_nomws;
mw->mw_flags = 0;
return mw;
out_nomws:
......
......@@ -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.
*
......
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