xdp: unpin xdp umem pages in error path

Fix mem leak caused by missed unpin routine for umem pages.

Fixes: 8aef7340 ("xsk: introduce xdp_umem_page")
Signed-off-by: Ivan Khoronzhuk <ivan.khoronzhuk@linaro.org>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

net/xdp/xdp_umem.c

@@ -365,7 +365,7 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 	umem->pages = kcalloc(umem->npgs, sizeof(*umem->pages), GFP_KERNEL);
 	if (!umem->pages) {
 		err = -ENOMEM;
-		goto out_account;
+		goto out_pin;
 	}
 
 	for (i = 0; i < umem->npgs; i++)
@@ -373,6 +373,8 @@ static int xdp_umem_reg(struct xdp_umem *umem, struct xdp_umem_reg *mr)
 
 	return 0;
 
+out_pin:
+	xdp_umem_unpin_pages(umem);
 out_account:
 	xdp_umem_unaccount_pages(umem);
 	return err;