Commit 339122ab authored by Baoquan He's avatar Baoquan He Committed by Andrew Morton
Browse files

mm/gup: remove gup_fast_pgd_leaf() and clean up the relevant codes 

In the current kernel, only pud huge page is supported in some
architectures.  P4d and pgd huge pages haven't been supported yet.  And in
mm/gup.c, there's no pgd huge page handling in the follow_page_mask() code
path.  Hence it doesn't make sense to only have gup_fast_pgd_leaf() in
gup_fast code path.

Here remove gup_fast_pgd_leaf() and clean up the relevant codes.

Link: https://lkml.kernel.org/r/20250410035717.473207-4-bhe@redhat.com


Signed-off-by: default avatarBaoquan He <bhe@redhat.com>
Reviewed-by: default avatarOscar Salvador <osalvador@suse.de>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Cc: Yanjun.Zhu <yanjun.zhu@linux.dev>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent ede27b7e

mm/gup.c

+3 −46
Original line number Diff line number Diff line
@@ -3172,46 +3172,6 @@ static int gup_fast_pud_leaf(pud_t orig, pud_t *pudp, unsigned long addr, 
	return 1;

}



static int gup_fast_pgd_leaf(pgd_t orig, pgd_t *pgdp, unsigned long addr,

		unsigned long end, unsigned int flags, struct page **pages,

		int *nr)

{

	int refs;

	struct page *page;

	struct folio *folio;



	if (!pgd_access_permitted(orig, flags & FOLL_WRITE))

		return 0;



	BUILD_BUG_ON(pgd_devmap(orig));



	page = pgd_page(orig);

	refs = record_subpages(page, PGDIR_SIZE, addr, end, pages + *nr);



	folio = try_grab_folio_fast(page, refs, flags);

	if (!folio)

		return 0;



	if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) {

		gup_put_folio(folio, refs, flags);

		return 0;

	}



	if (!pgd_write(orig) && gup_must_unshare(NULL, flags, &folio->page)) {

		gup_put_folio(folio, refs, flags);

		return 0;

	}



	if (!gup_fast_folio_allowed(folio, flags)) {

		gup_put_folio(folio, refs, flags);

		return 0;

	}



	*nr += refs;

	folio_set_referenced(folio);

	return 1;

}



static int gup_fast_pmd_range(pud_t *pudp, pud_t pud, unsigned long addr,

		unsigned long end, unsigned int flags, struct page **pages,

		int *nr)
@@ -3306,11 +3266,8 @@ static void gup_fast_pgd_range(unsigned long addr, unsigned long end, 
		next = pgd_addr_end(addr, end);

		if (pgd_none(pgd))

			return;

		if (unlikely(pgd_leaf(pgd))) {

			if (!gup_fast_pgd_leaf(pgd, pgdp, addr, next, flags,

					       pages, nr))

				return;

		} else if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags,

		BUILD_BUG_ON(pgd_leaf(pgd));

		if (!gup_fast_p4d_range(pgdp, pgd, addr, next, flags,

					pages, nr))

			return;

	} while (pgdp++, addr = next, addr != end);