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Commit 652ea695 authored by Nick Piggin's avatar Nick Piggin Committed by Linus Torvalds
Browse files

x86: support 1GB hugepages with get_user_pages_lockless() 



Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bc40d73c

arch/x86/mm/gup.c

+40 −3
Original line number Diff line number Diff line
@@ -124,7 +124,7 @@ static noinline int gup_huge_pmd(pmd_t pmd, unsigned long addr, 


	refs = 0;

	head = pte_page(pte);

	page = head + ((addr & ~HPAGE_MASK) >> PAGE_SHIFT);

	page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);

	do {

		VM_BUG_ON(compound_head(page) != head);

		pages[*nr] = page;
@@ -162,6 +162,38 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, 
	return 1;

}



static noinline int gup_huge_pud(pud_t pud, unsigned long addr,

		unsigned long end, int write, struct page **pages, int *nr)

{

	unsigned long mask;

	pte_t pte = *(pte_t *)&pud;

	struct page *head, *page;

	int refs;



	mask = _PAGE_PRESENT|_PAGE_USER;

	if (write)

		mask |= _PAGE_RW;

	if ((pte_val(pte) & mask) != mask)

		return 0;

	/* hugepages are never "special" */

	VM_BUG_ON(pte_val(pte) & _PAGE_SPECIAL);

	VM_BUG_ON(!pfn_valid(pte_pfn(pte)));



	refs = 0;

	head = pte_page(pte);

	page = head + ((addr & ~PUD_MASK) >> PAGE_SHIFT);

	do {

		VM_BUG_ON(compound_head(page) != head);

		pages[*nr] = page;

		(*nr)++;

		page++;

		refs++;

	} while (addr += PAGE_SIZE, addr != end);

	get_head_page_multiple(head, refs);



	return 1;

}



static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end,

			int write, struct page **pages, int *nr)

{
@@ -175,8 +207,13 @@ static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, 
		next = pud_addr_end(addr, end);

		if (pud_none(pud))

			return 0;

		if (unlikely(pud_large(pud))) {

			if (!gup_huge_pud(pud, addr, next, write, pages, nr))

				return 0;

		} else {

			if (!gup_pmd_range(pud, addr, next, write, pages, nr))

				return 0;

		}

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



	return 1;