svcrdma: Find rmsgp more reliably
authorChuck Lever <chuck.lever@oracle.com>
Tue, 13 Jan 2015 16:03:11 +0000 (11:03 -0500)
committerJ. Bruce Fields <bfields@redhat.com>
Thu, 15 Jan 2015 20:01:45 +0000 (15:01 -0500)
commite5523bd28101869c85856247fc120faaf72bd232
treee7a485eb027f66d2a17c67b53fd7dd50a77a4e36
parent3fe04ee9f91084e7e6e999b09b8b15bcf97375e8
svcrdma: Find rmsgp more reliably

xdr_start() can return the wrong rmsgp address if an assumption
about how the xdr_buf was constructed changes.  When it gets it
wrong, the client receives a reply that has gibberish in the
RPC/RDMA header, preventing it from matching a waiting RPC request.

Instead, make (and document) just one assumption: that the RDMA
header for the client's RPC call is at the start of the first page
in rq_pages.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
net/sunrpc/xprtrdma/svc_rdma_sendto.c