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Commit dfc2f91a authored by Paul Mundt's avatar Paul Mundt
Browse files

nommu: provide follow_pfn(). 



With the introduction of follow_pfn() as an exported symbol, modules have
begun making use of it. Unfortunately this was not reflected on nommu at
the time, so the in-tree users have subsequently all blown up with link
errors there.

This provides a simple follow_pfn() that just returns addr >> PAGE_SHIFT,
which will do the right thing on nommu. There is no need to do range
checking within the vma, as the find_vma() case will already take care of
this.

Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
parent 1fbcf371

mm/nommu.c

+21 −0
Original line number Original line Diff line number Diff line
@@ -240,6 +240,27 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm, 
}

}

EXPORT_SYMBOL(get_user_pages);

EXPORT_SYMBOL(get_user_pages);





/**

 * follow_pfn - look up PFN at a user virtual address

 * @vma: memory mapping

 * @address: user virtual address

 * @pfn: location to store found PFN

 *

 * Only IO mappings and raw PFN mappings are allowed.

 *

 * Returns zero and the pfn at @pfn on success, -ve otherwise.

 */

int follow_pfn(struct vm_area_struct *vma, unsigned long address,

	unsigned long *pfn)

{

	if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))

		return -EINVAL;



	*pfn = address >> PAGE_SHIFT;

	return 0;

}

EXPORT_SYMBOL(follow_pfn);



DEFINE_RWLOCK(vmlist_lock);

DEFINE_RWLOCK(vmlist_lock);

struct vm_struct *vmlist;

struct vm_struct *vmlist;