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Commit 90eceff1 authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
Browse files

mm: introduce __p4d_alloc() 



For full 5-level paging we need a helper to allocate p4d page table.

Signed-off-by: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c2febafc

mm/memory.c

+23 −0
Original line number Diff line number Diff line
@@ -3906,6 +3906,29 @@ int handle_mm_fault(struct vm_area_struct *vma, unsigned long address, 
}

EXPORT_SYMBOL_GPL(handle_mm_fault);



#ifndef __PAGETABLE_P4D_FOLDED

/*

 * Allocate p4d page table.

 * We've already handled the fast-path in-line.

 */

int __p4d_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)

{

	p4d_t *new = p4d_alloc_one(mm, address);

	if (!new)

		return -ENOMEM;



	smp_wmb(); /* See comment in __pte_alloc */



	spin_lock(&mm->page_table_lock);

	if (pgd_present(*pgd))		/* Another has populated it */

		p4d_free(mm, new);

	else

		pgd_populate(mm, pgd, new);

	spin_unlock(&mm->page_table_lock);

	return 0;

}

#endif /* __PAGETABLE_P4D_FOLDED */



#ifndef __PAGETABLE_PUD_FOLDED

/*

 * Allocate page upper directory.