Commit 7fc7e2ee authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Remove (at least temporarily) the "incomplete PFN mapping" support 



With the previous commit, we can handle arbitrary shared re-mappings
even without this complexity, and since the only known private mappings
are for strange users of /dev/mem (which never create an incomplete one),
there seems to be no reason to support it.

Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fb155c16

include/linux/mm.h

+0 −1
Original line number Diff line number Diff line
@@ -163,7 +163,6 @@ extern unsigned int kobjsize(const void *objp); 
#define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */

#define VM_NONLINEAR	0x00800000	/* Is non-linear (remap_file_pages) */

#define VM_MAPPED_COPY	0x01000000	/* T if mapped copy of data (nommu mmap) */

#define VM_INCOMPLETE	0x02000000	/* Strange partial PFN mapping marker */



#ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */

#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS

mm/memory.c

+1 −45
Original line number Diff line number Diff line
@@ -1227,50 +1227,6 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, struct page * 
}

EXPORT_SYMBOL(vm_insert_page);



/*

 * Somebody does a pfn remapping that doesn't actually work as a vma.

 *

 * Do it as individual pages instead, and warn about it. It's bad form,

 * and very inefficient.

 */

static int incomplete_pfn_remap(struct vm_area_struct *vma,

		unsigned long start, unsigned long end,

		unsigned long pfn, pgprot_t prot)

{

	static int warn = 10;

	struct page *page;

	int retval;



	if (!(vma->vm_flags & VM_INCOMPLETE)) {

		if (warn) {

			warn--;

			printk("%s does an incomplete pfn remapping", current->comm);

			dump_stack();

		}

	}

	vma->vm_flags |= VM_INCOMPLETE | VM_IO | VM_RESERVED;



	if (start < vma->vm_start || end > vma->vm_end)

		return -EINVAL;



	if (!pfn_valid(pfn))

		return -EINVAL;



	page = pfn_to_page(pfn);

	if (!PageReserved(page))

		return -EINVAL;



	retval = 0;

	while (start < end) {

		retval = insert_page(vma->vm_mm, start, page, prot);

		if (retval < 0)

			break;

		start += PAGE_SIZE;

		page++;

	}

	return retval;

}



/*

 * maps a range of physical memory into the requested pages. the old

 * mappings are removed. any references to nonexistent pages results
@@ -1365,7 +1321,7 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr, 
	 */

	if (!(vma->vm_flags & VM_SHARED)) {

		if (addr != vma->vm_start || end != vma->vm_end)

			return incomplete_pfn_remap(vma, addr, end, pfn, prot);

			return -EINVAL;

		vma->vm_pgoff = pfn;

	}