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

[Boris Ostrovsky]

On 07/30/2018 05:02 AM, Stephen Rothwell wrote:
> Hi all,
>
> 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) {


I clearly missed this (aaefcabe9c25) patch but now that I am looking at
it I don't think I understand the logic for changes in
list_for_each_entry() loops.

Aren't we ending up never unmapping grant pages? Michal, can you explain
what you are trying to do here?


-boris

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