Commit d8ddc099 authored by Matthew Wilcox (Oracle)'s avatar Matthew Wilcox (Oracle)
Browse files

mm/gup: Add gup_put_folio() 



Convert put_compound_head() to gup_put_folio() and hpage_pincount_sub()
to folio_pincount_sub().  This removes the last call to put_page_refs(),
so delete it.  Add a temporary put_compound_head() wrapper which will
be deleted by the end of this series.

Signed-off-by: default avatarMatthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarWilliam Kucharski <william.kucharski@oracle.com>
parent 40fcc7fc

mm/gup.c

+12 −26
Original line number Diff line number Diff line
@@ -29,23 +29,6 @@ struct follow_page_context { 
	unsigned int page_mask;

};



/* Equivalent to calling put_page() @refs times. */

static void put_page_refs(struct page *page, int refs)

{

#ifdef CONFIG_DEBUG_VM

	if (VM_WARN_ON_ONCE_PAGE(page_ref_count(page) < refs, page))

		return;

#endif



	/*

	 * Calling put_page() for each ref is unnecessarily slow. Only the last

	 * ref needs a put_page().

	 */

	if (refs > 1)

		page_ref_sub(page, refs - 1);

	put_page(page);

}



/*

 * Return the folio with ref appropriately incremented,

 * or NULL if that failed.
@@ -156,20 +139,23 @@ struct page *try_grab_compound_head(struct page *page, 
	return &try_grab_folio(page, refs, flags)->page;

}



static void put_compound_head(struct page *page, int refs, unsigned int flags)

static void gup_put_folio(struct folio *folio, int refs, unsigned int flags)

{

	VM_BUG_ON_PAGE(PageTail(page), page);



	if (flags & FOLL_PIN) {

		mod_node_page_state(page_pgdat(page), NR_FOLL_PIN_RELEASED,

				    refs);

		if (PageHead(page))

			atomic_sub(refs, compound_pincount_ptr(page));

		node_stat_mod_folio(folio, NR_FOLL_PIN_RELEASED, refs);

		if (folio_test_large(folio))

			atomic_sub(refs, folio_pincount_ptr(folio));

		else

			refs *= GUP_PIN_COUNTING_BIAS;

	}



	put_page_refs(page, refs);

	folio_put_refs(folio, refs);

}



static void put_compound_head(struct page *page, int refs, unsigned int flags)

{

	VM_BUG_ON_PAGE(PageTail(page), page);

	gup_put_folio((struct folio *)page, refs, flags);

}



/**
@@ -230,7 +216,7 @@ bool __must_check try_grab_page(struct page *page, unsigned int flags) 
 */

void unpin_user_page(struct page *page)

{

	put_compound_head(compound_head(page), 1, FOLL_PIN);

	gup_put_folio(page_folio(page), 1, FOLL_PIN);

}

EXPORT_SYMBOL(unpin_user_page);