[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, 13 insertions, 3 deletions

diff --git a/net/sunrpc/xdr.c b/net/sunrpc/xdr.c
index f86d1baa6302..65b268d39782 100644
--- a/net/sunrpc/xdr.c
+++ b/net/sunrpc/xdr.c
@@ -176,7 +176,7 @@ xdr_inline_pages(struct xdr_buf *xdr, unsigned int offset,
         xdr->buflen += len;
 }
 
-void
+int
 xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base,
                           skb_reader_t *desc,
                           skb_read_actor_t copy_actor)
@@ -190,7 +190,7 @@ xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base,
                 len -= base;
                 ret = copy_actor(desc, (char *)xdr->head[0].iov_base + base, len);
                 if (ret != len || !desc->count)
-                        return;
+                        return 0;
                 base = 0;
         } else
                 base -= len;
@@ -210,6 +210,14 @@ xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base,
         do {
                 char *kaddr;
 
+                /* ACL likes to be lazy in allocating pages - ACLs
+                 * are small by default but can get huge. */
+                if (unlikely(*ppage == NULL)) {
+                        *ppage = alloc_page(GFP_ATOMIC);
+                        if (unlikely(*ppage == NULL))
+                                return -ENOMEM;
+                }
+
                 len = PAGE_CACHE_SIZE;
                 kaddr = kmap_atomic(*ppage, KM_SKB_SUNRPC_DATA);
                 if (base) {
@@ -226,13 +234,15 @@ xdr_partial_copy_from_skb(struct xdr_buf *xdr, unsigned int base,
                 flush_dcache_page(*ppage);
                 kunmap_atomic(kaddr, KM_SKB_SUNRPC_DATA);
                 if (ret != len || !desc->count)
-                        return;
+                        return 0;
                 ppage++;
         } while ((pglen -= len) != 0);
 copy_tail:
         len = xdr->tail[0].iov_len;
         if (base < len)
                 copy_actor(desc, (char *)xdr->tail[0].iov_base + base, len - base);
+
+        return 0;
 }