Subject: Re: linux-next: manual merge of the akpm-current tree with the xen-tip tree

From: Stephen Rothwell <[email-masked]>
Date: Thu, 16 Aug 2018 10:05:11 +1000

Hi all,

On Mon, 30 Jul 2018 19:02:10 +1000 Stephen Rothwell <[email-masked]> wrote:
>
> Today's linux-next merge of the akpm-current tree got a conflict in:
> 
>   drivers/xen/gntdev.c
> 
> between commit:
> 
>   1d3145675538 ("xen/gntdev: Make private routines/structures accessible")
> 
> from the xen-tip tree and commit:
> 
>   aaefcabe9c25 ("mm, oom: distinguish blockable mode for mmu notifiers")
> 
> from the akpm-current tree.
> 
> I fixed it up (see below) and can carry the fix as necessary. This
> is now fixed as far as linux-next is concerned, but any non trivial
> conflicts should be mentioned to your upstream maintainer when your tree
> is submitted for merging.  You may also want to consider cooperating
> with the maintainer of the conflicting tree to minimise any particularly
> complex conflicts.
> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc drivers/xen/gntdev.c
> index c866a62f766d,55b4f0e3f4d6..000000000000
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@@ -479,7 -441,20 +479,20 @@@ static const struct vm_operations_struc
>   
>   /* ------------------------------------------------------------------ */
>   
>  -static bool in_range(struct grant_map *map,
> ++static bool in_range(struct gntdev_grant_map *map,
> + 			      unsigned long start, unsigned long end)
> + {
> + 	if (!map->vma)
> + 		return false;
> + 	if (map->vma->vm_start >= end)
> + 		return false;
> + 	if (map->vma->vm_end <= start)
> + 		return false;
> + 
> + 	return true;
> + }
> + 
>  -static void unmap_if_in_range(struct grant_map *map,
>  +static void unmap_if_in_range(struct gntdev_grant_map *map,
>   			      unsigned long start, unsigned long end)
>   {
>   	unsigned long mstart, mend;
> @@@ -503,15 -472,26 +510,26 @@@
>   	WARN_ON(err);
>   }
>   
> - static void mn_invl_range_start(struct mmu_notifier *mn,
> + static int mn_invl_range_start(struct mmu_notifier *mn,
>   				struct mm_struct *mm,
> - 				unsigned long start, unsigned long end)
> + 				unsigned long start, unsigned long end,
> + 				bool blockable)
>   {
>   	struct gntdev_priv *priv = container_of(mn, struct gntdev_priv, mn);
>  -	struct grant_map *map;
>  +	struct gntdev_grant_map *map;
> + 	int ret = 0;
> + 
> + 	/* TODO do we really need a mutex here? */
> + 	if (blockable)
> + 		mutex_lock(&priv->lock);
> + 	else if (!mutex_trylock(&priv->lock))
> + 		return -EAGAIN;
>   
> - 	mutex_lock(&priv->lock);
>   	list_for_each_entry(map, &priv->maps, next) {
> + 		if (in_range(map, start, end)) {
> + 			ret = -EAGAIN;
> + 			goto out_unlock;
> + 		}
>   		unmap_if_in_range(map, start, end);
>   	}
>   	list_for_each_entry(map, &priv->freeable_maps, next) {

This is now a conflict between Linus' tree and the akpm-current tree.

-- 
Cheers,
Stephen Rothwell