Subject: Re: linux-next: manual merge of the folio tree with the xfs tree

From: "Darrick J. Wong" <[email-masked]>
Date: Wed, 11 Aug 2021 07:43:45 -0700

On Wed, Aug 11, 2021 at 05:42:31PM +1000, Stephen Rothwell wrote:
> Hi all,
> 
> Today's linux-next merge of the folio tree got a conflict in:
> 
>   mm/util.c
> 
> between commit:
> 
>   de2860f46362 ("mm: Add kvrealloc()")
> 
> from the xfs tree and commit:
> 
>   3bc0556bade4 ("mm: Add folio_raw_mapping()")
> 
> from the folio 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.

Hmmm.  Seeing as krealloc lives in mm/slab_common.c anyway, I might just
move this function there, and (hopefully) avoid this conflict.

--D

> 
> -- 
> Cheers,
> Stephen Rothwell
> 
> diff --cc mm/util.c
> index d06e48b28eec,e8fa30e48447..000000000000
> --- a/mm/util.c
> +++ b/mm/util.c
> @@@ -660,31 -635,6 +660,21 @@@ void kvfree_sensitive(const void *addr
>   }
>   EXPORT_SYMBOL(kvfree_sensitive);
>   
>  +void *kvrealloc(const void *p, size_t oldsize, size_t newsize, gfp_t flags)
>  +{
>  +	void *newp;
>  +
>  +	if (oldsize >= newsize)
>  +		return (void *)p;
>  +	newp = kvmalloc(newsize, flags);
>  +	if (!newp)
>  +		return NULL;
>  +	memcpy(newp, p, oldsize);
>  +	kvfree(p);
>  +	return newp;
>  +}
>  +EXPORT_SYMBOL(kvrealloc);
>  +
> - static inline void *__page_rmapping(struct page *page)
> - {
> - 	unsigned long mapping;
> - 
> - 	mapping = (unsigned long)page->mapping;
> - 	mapping &= ~PAGE_MAPPING_FLAGS;
> - 
> - 	return (void *)mapping;
> - }
> - 
>   /* Neutral page->mapping pointer to address_space or anon_vma or other */
>   void *page_rmapping(struct page *page)
>   {