Re: [PATCH] xen/gnttab: leave lazy MMU mode in the case of a m2poverride failure

From: Konrad Rzeszutek Wilk
Date: Fri Nov 22 2013 - 10:22:32 EST


On Wed, Nov 20, 2013 at 12:11:35PM -0800, Matt Wilson wrote:
> From: Matt Wilson <msw@xxxxxxxxxx>
>
> Commit f62805f1 introduced a bug where lazy MMU mode isn't exited if a
> m2p_add/remove_override call fails.

Stefano?

>
> Cc: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
> Cc: David Vrabel <david.vrabel@xxxxxxxxxx>
> Cc: Anthony Liguori <aliguori@xxxxxxxxxx>
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Signed-off-by: Matt Wilson <msw@xxxxxxxxxx>
> ---
> 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 62ccf54..0283871 100644
> --- a/drivers/xen/grant-table.c
> +++ b/drivers/xen/grant-table.c
> @@ -930,9 +930,10 @@ 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();
>
> @@ -969,9 +970,10 @@ 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();
>
> --
> 1.7.9.5
>
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