On 08/15/2018 08:05 PM, Stephen Rothwell wrote:
> Hi all,
>
> On Mon, 30 Jul 2018 19:02:10 +1000 Stephen Rothwell <sfr@canb.auug.org.au> 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);


I think I mentioned this earlier --- this doesn't look right. Not the
conflict resolution but the original patch.

Should I send a patch against -next? Or -mm?


-boris