[PATCH v12 43/49] sunrpc: Allow to demand-allocate pages to encode into

[Andreas Gruenbacher <agruenba@xxxxxxxxxx>]

When encoding large, variable-length objects such as acls into xdr_bufs,
it is easier to allocate buffer pages on demand rather than precomputing
the required buffer size.

Signed-off-by: Andreas Gruenbacher <agruenba@xxxxxxxxxx>
---
 net/sunrpc/xdr.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index 4439ac4..63c1c36 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -537,6 +537,15 @@ static __be32 *xdr_get_next_encode_buffer(struct 
xdr_stream *xdr,
         */
        xdr->scratch.iov_base = xdr->p;
        xdr->scratch.iov_len = frag1bytes;
+
+       if (!*xdr->page_ptr) {
+               struct page *page = alloc_page(GFP_NOFS);
+
+               if (!page)
+                       return NULL;
+               *xdr->page_ptr = page;
+       }
+
        p = page_address(*xdr->page_ptr);
        /*
         * Note this is where the next encode will start after we've
-- 
2.5.0