pull manipulations of rpc_cred inside alloc_nfs_open_context()

No need to duplicate them in both callers; make it return
ERR_PTR(-ENOMEM) on allocation failure instead of NULL and
it'll be able to report rpc_lookup_cred() failures just
fine.  Callers are much happier that way...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/nfs/dir.c

@@ -1368,18 +1368,7 @@ static fmode_t flags_to_mode(int flags)
 
 static struct nfs_open_context *create_nfs_open_context(struct dentry *dentry, int open_flags)
 {
-	struct nfs_open_context *ctx;
-	struct rpc_cred *cred;
-	fmode_t fmode = flags_to_mode(open_flags);
-
-	cred = rpc_lookup_cred();
-	if (IS_ERR(cred))
-		return ERR_CAST(cred);
-	ctx = alloc_nfs_open_context(dentry, cred, fmode);
-	put_rpccred(cred);
-	if (ctx == NULL)
-		return ERR_PTR(-ENOMEM);
-	return ctx;
+	return alloc_nfs_open_context(dentry, flags_to_mode(open_flags));
 }
 
 static int do_open(struct inode *inode, struct file *filp)

fs/nfs/inode.c

@@ -629,23 +629,28 @@ void nfs_close_context(struct nfs_open_context *ctx, int is_sync)
 	nfs_revalidate_inode(server, inode);
 }
 
-struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, struct rpc_cred *cred, fmode_t f_mode)
+struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode)
 {
 	struct nfs_open_context *ctx;
+	struct rpc_cred *cred = rpc_lookup_cred();
+	if (IS_ERR(cred))
+		return ERR_CAST(cred);
 
 	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
-	if (ctx != NULL) {
-		nfs_sb_active(dentry->d_sb);
-		ctx->dentry = dget(dentry);
-		ctx->cred = get_rpccred(cred);
-		ctx->state = NULL;
-		ctx->mode = f_mode;
-		ctx->flags = 0;
-		ctx->error = 0;
-		nfs_init_lock_context(&ctx->lock_context);
-		ctx->lock_context.open_context = ctx;
-		INIT_LIST_HEAD(&ctx->list);
+	if (!ctx) {
+		put_rpccred(cred);
+		return ERR_PTR(-ENOMEM);
 	}
+	nfs_sb_active(dentry->d_sb);
+	ctx->dentry = dget(dentry);
+	ctx->cred = cred;
+	ctx->state = NULL;
+	ctx->mode = f_mode;
+	ctx->flags = 0;
+	ctx->error = 0;
+	nfs_init_lock_context(&ctx->lock_context);
+	ctx->lock_context.open_context = ctx;
+	INIT_LIST_HEAD(&ctx->list);
 	return ctx;
 }
 
@@ -738,15 +743,10 @@ static void nfs_file_clear_open_context(struct file *filp)
 int nfs_open(struct inode *inode, struct file *filp)
 {
 	struct nfs_open_context *ctx;
-	struct rpc_cred *cred;
 
-	cred = rpc_lookup_cred();
-	if (IS_ERR(cred))
-		return PTR_ERR(cred);
-	ctx = alloc_nfs_open_context(filp->f_path.dentry, cred, filp->f_mode);
-	put_rpccred(cred);
-	if (ctx == NULL)
-		return -ENOMEM;
+	ctx = alloc_nfs_open_context(filp->f_path.dentry, filp->f_mode);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
 	nfs_file_set_open_context(filp, ctx);
 	put_nfs_open_context(ctx);
 	nfs_fscache_set_inode_cookie(inode, filp);

include/linux/nfs_fs.h

@@ -373,7 +373,7 @@ extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr);
 extern struct nfs_open_context *get_nfs_open_context(struct nfs_open_context *ctx);
 extern void put_nfs_open_context(struct nfs_open_context *ctx);
 extern struct nfs_open_context *nfs_find_open_context(struct inode *inode, struct rpc_cred *cred, fmode_t mode);
-extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, struct rpc_cred *cred, fmode_t f_mode);
+extern struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry, fmode_t f_mode);
 extern void nfs_file_set_open_context(struct file *filp, struct nfs_open_context *ctx);
 extern struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx);
 extern void nfs_put_lock_context(struct nfs_lock_context *l_ctx);