[PATCH] RPC: Lazy RPC receive buffer allocation

 Signed-off-by: Olaf Kirch <okir@suse.de>
 Signed-off-by: Andreas Gruenbacher <agruen@suse.de>
 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 22 insertions, 4 deletions

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index c74a6bb94074..a180ed4952d6 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -725,7 +725,8 @@ csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
                 goto no_checksum;
 
         desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
-        xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits);
+        if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0)
+                return -1;
         if (desc.offset != skb->len) {
                 unsigned int csum2;
                 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
@@ -737,7 +738,8 @@ csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
                 return -1;
         return 0;
 no_checksum:
-        xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits);
+        if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0)
+                return -1;
         if (desc.count)
                 return -1;
         return 0;
@@ -907,6 +909,7 @@ tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
         struct rpc_rqst *req;
         struct xdr_buf *rcvbuf;
         size_t len;
+        int r;
 
         /* Find and lock the request corresponding to this xid */
         spin_lock(&xprt->sock_lock);
@@ -927,16 +930,30 @@ tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
                 len = xprt->tcp_reclen - xprt->tcp_offset;
                 memcpy(&my_desc, desc, sizeof(my_desc));
                 my_desc.count = len;
-                xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
+                r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
                                           &my_desc, tcp_copy_data);
                 desc->count -= len;
                 desc->offset += len;
         } else
-                xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
+                r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
                                           desc, tcp_copy_data);
         xprt->tcp_copied += len;
         xprt->tcp_offset += len;
 
+        if (r < 0) {
+                /* Error when copying to the receive buffer,
+                 * usually because we weren't able to allocate
+                 * additional buffer pages. All we can do now
+                 * is turn off XPRT_COPY_DATA, so the request
+                 * will not receive any additional updates,
+                 * and time out.
+                 * Any remaining data from this record will
+                 * be discarded.
+                 */
+                xprt->tcp_flags &= ~XPRT_COPY_DATA;
+                goto out;
+        }
+
         if (xprt->tcp_copied == req->rq_private_buf.buflen)
                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
         else if (xprt->tcp_offset == xprt->tcp_reclen) {
@@ -949,6 +966,7 @@ tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
                                 req->rq_task->tk_pid);
                 xprt_complete_rqst(xprt, req, xprt->tcp_copied);
         }
+out:
         spin_unlock(&xprt->sock_lock);
         tcp_check_recm(xprt);
 }