[PATCH v3 01/12] xprtrdma: Cap size of callback buffer resources

Chuck Lever
2016-11-29T15:52:08Z

When the inline threshold size is set to large values (say, 32KB)
any NFSv4.1 CB request from the server gets a reply with status
NFS4ERR_RESOURCE.

Looks like there are some upper layer assumptions about the maximum
size of a reply (for example, in process_op). Cap the size of the
NFSv4 client's reply resources at a page.

Signed-off-by: Chuck Lever <chuck.lever-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>
---
net/sunrpc/xprtrdma/backchannel.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/sunrpc/xprtrdma/backchannel.c b/net/sunrpc/xprtrdma/backchannel.c
index 2c472e1..24fedd4 100644
--- a/net/sunrpc/xprtrdma/backchannel.c
+++ b/net/sunrpc/xprtrdma/backchannel.c
@@ -55,7 +55,8 @@ static int rpcrdma_bc_setup_rqst(struct rpcrdma_xprt *r_xprt,
if (IS_ERR(rb))
goto out_fail;
req->rl_sendbuf = rb;
- xdr_buf_init(&rqst->rq_snd_buf, rb->rg_base, size);
+ xdr_buf_init(&rqst->rq_snd_buf, rb->rg_base,
+ min_t(size_t, size, PAGE_SIZE));
rpcrdma_set_xprtdata(rqst, req);
return 0;

@@ -191,6 +192,7 @@ size_t xprt_rdma_bc_maxpayload(struct rpc_xprt *xprt)
size_t maxmsg;

maxmsg = min_t(unsigned int, cdata->inline_rsize, cdata->inline_wsize);
+ maxmsg = min_t(unsigned int, maxmsg, PAGE_SIZE);
return maxmsg - RPCRDMA_HDRLEN_MIN;