xen/gnttab: leave lazy MMU mode in the case of a m2p override failure

[Matt Wilson]

commit 14883a75ec76b44759385fb12629f4a0f1aef4e3 upstream.

Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a
m2p_add/remove_override call fails.

Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Reviewed-by: David Vrabel <david.vrabel@xxxxxxxxxx>
Reviewed-by: Anthony Liguori <aliguori@xxxxxxxxxx>
Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Matt Wilson <msw@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 drivers/xen/grant-table.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index 51be226..b146bfd 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -920,9 +920,10 @@ int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
 		ret = m2p_add_override(mfn, pages[i], kmap_ops ?
 				       &kmap_ops[i] : NULL);
 		if (ret)
-			return ret;
+			goto out;
 	}

+ out:
 	if (lazy)
 		arch_leave_lazy_mmu_mode();

@@ -953,9 +954,10 @@ int gnttab_unmap_refs(struct gnttab_unmap_grant_ref *unmap_ops,
 		ret = m2p_remove_override(pages[i], kmap_ops ?
 				       &kmap_ops[i] : NULL);
 		if (ret)
-			return ret;
+			goto out;
 	}

+ out:
 	if (lazy)
 		arch_leave_lazy_mmu_mode();

--
1.8.3.2

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