SUNRPC: Refactor logic to NUL-terminate strings in pages

Clean up: Introduce a helper to '\0'-terminate XDR strings
that are placed in a page in the page cache.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

3 files changed, 3 insertions, 14 deletions

diff --git a/fs/nfs/nfs2xdr.c b/fs/nfs/nfs2xdr.c
index e15bc0306d0c..79c74387a2fe 100644
--- a/fs/nfs/nfs2xdr.c
+++ b/fs/nfs/nfs2xdr.c
@@ -596,7 +596,6 @@ nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
         struct kvec *iov = rcvbuf->head;
         size_t hdrlen;
         u32 len, recvd;
-        char    *kaddr;
         int     status;
 
         if ((status = ntohl(*p++)))
@@ -623,10 +622,7 @@ nfs_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, void *dummy)
                 return -EIO;
         }
 
-        /* NULL terminate the string we got */
-        kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
-        kaddr[len+rcvbuf->page_base] = '\0';
-        kunmap_atomic(kaddr, KM_USER0);
+        xdr_terminate_string(rcvbuf, len);
         return 0;
 }
 
diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 89c40f8ec6e6..52b2fda66e63 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -824,7 +824,6 @@ nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
         struct kvec *iov = rcvbuf->head;
         size_t hdrlen;
         u32 len, recvd;
-        char    *kaddr;
         int     status;
 
         status = ntohl(*p++);
@@ -857,10 +856,7 @@ nfs3_xdr_readlinkres(struct rpc_rqst *req, __be32 *p, struct nfs_fattr *fattr)
                 return -EIO;
         }
 
-        /* NULL terminate the string we got */
-        kaddr = (char*)kmap_atomic(rcvbuf->pages[0], KM_USER0);
-        kaddr[len+rcvbuf->page_base] = '\0';
-        kunmap_atomic(kaddr, KM_USER0);
+        xdr_terminate_string(rcvbuf, len);
         return 0;
 }
 
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index b0bd7efe8100..86ab69eb149c 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -4299,7 +4299,6 @@ static int decode_readlink(struct xdr_stream *xdr, struct rpc_rqst *req)
         size_t hdrlen;
         u32 len, recvd;
         __be32 *p;
-        char *kaddr;
         int status;
 
         status = decode_op_hdr(xdr, OP_READLINK);
@@ -4330,9 +4329,7 @@ static int decode_readlink(struct xdr_stream *xdr, struct rpc_rqst *req)
          * and and null-terminate the text (the VFS expects
          * null-termination).
          */
-        kaddr = (char *)kmap_atomic(rcvbuf->pages[0], KM_USER0);
-        kaddr[len+rcvbuf->page_base] = '\0';
-        kunmap_atomic(kaddr, KM_USER0);
+        xdr_terminate_string(rcvbuf, len);
         return 0;
 out_overflow:
         print_overflow_msg(__func__, xdr);