svc: Add transport hdr size for defer/revisit
Some transports have a header in front of the RPC header. The current
defer/revisit processing considers only the iov_len and arg_len to
determine how much to back up when saving the original request
to revisit. Add a field to the rqstp structure to save the size
of the transport header so svc_defer can correctly compute
the start of a request.
Signed-off-by: Tom Tucker <tom@opengridcomputing.com>
Acked-by: Neil Brown <neilb@suse.de>
Reviewed-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Greg Banks <gnb@sgi.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 04eb20e..742ab46 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -217,6 +217,7 @@
void * rq_xprt_ctxt; /* transport specific context ptr */
struct svc_deferred_req*rq_deferred; /* deferred request we are replaying */
+ size_t rq_xprt_hlen; /* xprt header len */
struct xdr_buf rq_arg;
struct xdr_buf rq_res;
struct page * rq_pages[RPCSVC_MAXPAGES];
@@ -322,6 +323,7 @@
size_t addrlen;
union svc_addr_u daddr; /* where reply must come from */
struct cache_deferred_req handle;
+ size_t xprt_hlen;
int argslen;
__be32 args[0];
};
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 23165ae..000c7dc 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -29,7 +29,6 @@
#include <linux/sunrpc/types.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/xdr.h>
-#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>
@@ -859,10 +858,18 @@
svc_xprt_put(xprt);
}
+/*
+ * Save the request off for later processing. The request buffer looks
+ * like this:
+ *
+ * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
+ *
+ * This code can only handle requests that consist of an xprt-header
+ * and rpc-header.
+ */
static struct cache_deferred_req *svc_defer(struct cache_req *req)
{
struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
- int size = sizeof(struct svc_deferred_req) + (rqstp->rq_arg.len);
struct svc_deferred_req *dr;
if (rqstp->rq_arg.page_len)
@@ -871,8 +878,10 @@
dr = rqstp->rq_deferred;
rqstp->rq_deferred = NULL;
} else {
- int skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
+ size_t skip;
+ size_t size;
/* FIXME maybe discard if size too large */
+ size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
dr = kmalloc(size, GFP_KERNEL);
if (dr == NULL)
return NULL;
@@ -883,8 +892,12 @@
dr->addrlen = rqstp->rq_addrlen;
dr->daddr = rqstp->rq_daddr;
dr->argslen = rqstp->rq_arg.len >> 2;
- memcpy(dr->args, rqstp->rq_arg.head[0].iov_base-skip,
- dr->argslen<<2);
+ dr->xprt_hlen = rqstp->rq_xprt_hlen;
+
+ /* back up head to the start of the buffer and copy */
+ skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
+ memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
+ dr->argslen << 2);
}
svc_xprt_get(rqstp->rq_xprt);
dr->xprt = rqstp->rq_xprt;
@@ -900,16 +913,21 @@
{
struct svc_deferred_req *dr = rqstp->rq_deferred;
- rqstp->rq_arg.head[0].iov_base = dr->args;
- rqstp->rq_arg.head[0].iov_len = dr->argslen<<2;
+ /* setup iov_base past transport header */
+ rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
+ /* The iov_len does not include the transport header bytes */
+ rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
rqstp->rq_arg.page_len = 0;
- rqstp->rq_arg.len = dr->argslen<<2;
+ /* The rq_arg.len includes the transport header bytes */
+ rqstp->rq_arg.len = dr->argslen<<2;
rqstp->rq_prot = dr->prot;
memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
rqstp->rq_addrlen = dr->addrlen;
+ /* Save off transport header len in case we get deferred again */
+ rqstp->rq_xprt_hlen = dr->xprt_hlen;
rqstp->rq_daddr = dr->daddr;
rqstp->rq_respages = rqstp->rq_pages;
- return dr->argslen<<2;
+ return (dr->argslen<<2) - dr->xprt_hlen;
}
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index 343a85b..1d3e5fc 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -315,6 +315,8 @@
};
int len;
+ rqstp->rq_xprt_hlen = 0;
+
len = kernel_recvmsg(svsk->sk_sock, &msg, iov, nr, buflen,
msg.msg_flags);