IB/umem: Release pid in error and ODP flow

commit 828f6fa65ce7e80f77f5ab12942e44eb3d9d174e upstream.

1. Release pid before enter odp flow
2. Release pid when fail to allocate memory

Fixes: 87773dd ("IB: ib_umem_release() should decrement mm->pinned_vm from ib_umem_get")
Fixes: 8ada2c1 ("IB/core: Add support for on demand paging regions")
Signed-off-by: Kenneth Lee <liguozhu@hisilicon.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Reviewed-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Kenneth Lee

drivers/infiniband/core/umem.c

@@ -134,6 +134,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 		 IB_ACCESS_REMOTE_ATOMIC | IB_ACCESS_MW_BIND));
 
 	if (access & IB_ACCESS_ON_DEMAND) {
+		put_pid(umem->pid);
 		ret = ib_umem_odp_get(context, umem);
 		if (ret) {
 			kfree(umem);
@@ -149,6 +150,7 @@ struct ib_umem *ib_umem_get(struct ib_ucontext *context, unsigned long addr,
 
 	page_list = (struct page **) __get_free_page(GFP_KERNEL);
 	if (!page_list) {
+		put_pid(umem->pid);
 		kfree(umem);
 		return ERR_PTR(-ENOMEM);
 	}