@@ -242,7 +242,10 @@
ia->ri_max_segs = max_t(unsigned int, 1, RPCRDMA_MAX_DATA_SEGS /
ia->ri_max_frwr_depth);
- ia->ri_max_segs += 2; /* segments for head and tail buffers */
+ /* Reply chunks require segments for head and tail buffers */
+ ia->ri_max_segs += 2;
+ if (ia->ri_max_segs > RPCRDMA_MAX_HDR_SEGS)
+ ia->ri_max_segs = RPCRDMA_MAX_HDR_SEGS;
return 0;
}
@@ -255,7 +258,7 @@
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
return min_t(unsigned int, RPCRDMA_MAX_DATA_SEGS,
- RPCRDMA_MAX_HDR_SEGS * ia->ri_max_frwr_depth);
+ (ia->ri_max_segs - 2) * ia->ri_max_frwr_depth);
}
static void
@@ -696,8 +696,10 @@
* %-ENOTCONN if the caller should reconnect and call again
* %-EAGAIN if the caller should call again
* %-ENOBUFS if the caller should call again after a delay
- * %-EIO if a permanent error occurred and the request was not
- * sent. Do not try to send this message again.
+ * %-EMSGSIZE if encoding ran out of buffer space. The request
+ * was not sent. Do not try to send this message again.
+ * %-EIO if an I/O error occurred. The request was not sent.
+ * Do not try to send this message again.
*/
static int
xprt_rdma_send_request(struct rpc_rqst *rqst)
With certain combinations of krb5i/p, MR size, and r/wsize, I/O can fail with EMSGSIZE. This is because the calculated value of ri_max_segs (the max number of MRs per RPC) exceeded RPCRDMA_MAX_HDR_SEGS, which caused Read or Write list encoding to walk off the end of the transport header. Once that was addressed, the ro_maxpages result has to be corrected to account for the number of MRs needed for Reply chunks, which is 2 MRs smaller than a normal Read or Write chunk. Signed-off-by: Chuck Lever <chuck.lever@oracle.com> --- net/sunrpc/xprtrdma/frwr_ops.c | 7 +++++-- net/sunrpc/xprtrdma/transport.c | 6 ++++-- 2 files changed, 9 insertions(+), 4 deletions(-)