1 files changed, 7 insertions, 2 deletions

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 57333944af7f..bf1e792a65a0 100644
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -148,12 +148,12 @@ xdr_error:					\
         }                                       \
 } while (0)
 
-static __be32 *read_buf(struct nfsd4_compoundargs *argp, int nbytes)
+static __be32 *read_buf(struct nfsd4_compoundargs *argp, u32 nbytes)
 {
         /* We want more bytes than seem to be available.
          * Maybe we need a new page, maybe we have just run out
          */
-        int avail = (char*)argp->end - (char*)argp->p;
+        unsigned int avail = (char *)argp->end - (char *)argp->p;
         __be32 *p;
         if (avail + argp->pagelen < nbytes)
                 return NULL;
@@ -169,6 +169,11 @@ static __be32 *read_buf(struct nfsd4_compoundargs *argp, int nbytes)
                         return NULL;
                 
         }
+        /*
+         * The following memcpy is safe because read_buf is always
+         * called with nbytes > avail, and the two cases above both
+         * guarantee p points to at least nbytes bytes.
+         */
         memcpy(p, argp->p, avail);
         /* step to next page */
         argp->p = page_address(argp->pagelist[0]);