NFS: Convert nfs_get_lock_context to return an ERR_PTR on failure

We want to be able to distinguish between allocation failures, and
the case where the lock context is not needed (because there are no
locks).

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 5 insertions, 3 deletions

diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c
index 311a79681e2b..dfd764bd943d 100644
--- a/fs/nfs/pagelist.c
+++ b/fs/nfs/pagelist.c
@@ -102,6 +102,7 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
                    unsigned int offset, unsigned int count)
 {
         struct nfs_page         *req;
+        struct nfs_lock_context *l_ctx;
 
         /* try to allocate the request struct */
         req = nfs_page_alloc();
@@ -109,11 +110,12 @@ nfs_create_request(struct nfs_open_context *ctx, struct inode *inode,
                 return ERR_PTR(-ENOMEM);
 
         /* get lock context early so we can deal with alloc failures */
-        req->wb_lock_context = nfs_get_lock_context(ctx);
-        if (req->wb_lock_context == NULL) {
+        l_ctx = nfs_get_lock_context(ctx);
+        if (IS_ERR(l_ctx)) {
                 nfs_page_free(req);
-                return ERR_PTR(-ENOMEM);
+                return ERR_CAST(l_ctx);
         }
+        req->wb_lock_context = l_ctx;
 
         /* Initialize the request struct. Initially, we assume a
          * long write-back delay. This will be adjusted in