NFS: Charge open/lock file contexts to kmemcg

Allow kmemcg to limit the number of open/lock file contexts, in the same
way that it limits the parent file descriptors.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/dir.c

@@ -73,7 +73,7 @@ static struct nfs_open_dir_context *alloc_nfs_open_dir_context(struct inode *dir
 {
 	struct nfs_inode *nfsi = NFS_I(dir);
 	struct nfs_open_dir_context *ctx;
-	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
 	if (ctx != NULL) {
 		ctx->duped = 0;
 		ctx->attr_gencount = nfsi->attr_gencount;

fs/nfs/inode.c

@@ -952,7 +952,7 @@ struct nfs_lock_context *nfs_get_lock_context(struct nfs_open_context *ctx)
 	res = __nfs_find_lock_context(ctx);
 	rcu_read_unlock();
 	if (res == NULL) {
-		new = kmalloc(sizeof(*new), GFP_KERNEL);
+		new = kmalloc(sizeof(*new), GFP_KERNEL_ACCOUNT);
 		if (new == NULL)
 			return ERR_PTR(-ENOMEM);
 		nfs_init_lock_context(new);
@@ -1030,7 +1030,7 @@ struct nfs_open_context *alloc_nfs_open_context(struct dentry *dentry,
 {
 	struct nfs_open_context *ctx;
 
-	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL);
+	ctx = kmalloc(sizeof(*ctx), GFP_KERNEL_ACCOUNT);
 	if (!ctx)
 		return ERR_PTR(-ENOMEM);
 	nfs_sb_active(dentry->d_sb);