[PATCH 5.4 068/203] xprtrdma: Add unique trace points for posting Local Invalidate WRs

Greg Kroah-Hartman
2020-01-16T23:22:39Z

From: Chuck Lever <chuck.lever@oracle.com>

commit 4b93dab36f28e673725e5e6123ebfccf7697f96a upstream.

When adding frwr_unmap_async way back when, I re-used the existing
trace_xprtrdma_post_send() trace point to record the return code
of ib_post_send.

Unfortunately there are some cases where re-using that trace point
causes a crash. Instead, construct a trace point specific to posting
Local Invalidate WRs that will always be safe to use in that context,
and will act as a trace log eye-catcher for Local Invalidation.

Fixes: 847568942f93 ("xprtrdma: Remove fr_state")
Fixes: d8099feda483 ("xprtrdma: Reduce context switching due ... ")
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Tested-by: Bill Baker <bill.baker@oracle.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/trace/events/rpcrdma.h | 25 +++++++++++++++++++++++++
net/sunrpc/xprtrdma/frwr_ops.c | 4 ++--
2 files changed, 27 insertions(+), 2 deletions(-)

--- a/include/trace/events/rpcrdma.h
+++ b/include/trace/events/rpcrdma.h
@@ -735,6 +735,31 @@ TRACE_EVENT(xprtrdma_post_recvs,
)
);

+TRACE_EVENT(xprtrdma_post_linv,
+ TP_PROTO(
+ const struct rpcrdma_req *req,
+ int status
+ ),
+
+ TP_ARGS(req, status),
+
+ TP_STRUCT__entry(
+ __field(const void *, req)
+ __field(int, status)
+ __field(u32, xid)
+ ),
+
+ TP_fast_assign(
+ __entry->req = req;
+ __entry->status = status;
+ __entry->xid = be32_to_cpu(req->rl_slot.rq_xid);
+ ),
+
+ TP_printk("req=%p xid=0x%08x status=%d",
+ __entry->req, __entry->xid, __entry->status
+ )
+);
+
/**
** Completion events
**/
--- a/net/sunrpc/xprtrdma/frwr_ops.c
+++ b/net/sunrpc/xprtrdma/frwr_ops.c
@@ -570,7 +570,6 @@ void frwr_unmap_sync(struct rpcrdma_xprt
*/
bad_wr = NULL;
rc = ib_post_send(r_xprt->rx_ia.ri_id->qp, first, &bad_wr);
- trace_xprtrdma_post_send(req, rc);

/* The final LOCAL_INV WR in the chain is supposed to
* do the wake. If it was never posted, the wake will
@@ -583,6 +582,7 @@ void frwr_unmap_sync(struct rpcrdma_xprt

/* Recycle MRs in the LOCAL_INV chain that did not get posted.
*/
+ trace_xprtrdma_post_linv(req, rc);
while (bad_wr) {
frwr = container_of(bad_wr, struct rpcrdma_frwr,
fr_invwr);
@@ -673,12 +673,12 @@ void frwr_unmap_async(struct rpcrdma_xpr
*/
bad_wr = NULL;
rc = ib_post_send(r_xprt->rx_ia.ri_id->qp, first, &bad_wr);
- trace_xprtrdma_post_send(req, rc);
if (!rc)
return;

/* Recycle MRs in the LOCAL_INV chain that did not get posted.
*/
+ trace_xprtrdma_post_linv(req, rc);
while (bad_wr) {
frwr = container_of(bad_wr, struct rpcrdma_frwr, fr_invwr);
mr = container_of(frwr, struct rpcrdma_mr, frwr);