diff options
| author | Hugh Dickins <hugh@veritas.com> | 2007-01-29 21:24:08 +0000 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-01-30 08:33:32 -0800 |
| commit | 701dfbc1cbdd42b814dd76a885c4b73f97011d08 (patch) | |
| tree | 4a8e8185616e7cc9c115de564bd2c6d626662217 /mm | |
| parent | 8339f0008c47cdd921c73f6d53d5588b5484f93c (diff) | |
| download | lwn-701dfbc1cbdd42b814dd76a885c4b73f97011d08.tar.gz lwn-701dfbc1cbdd42b814dd76a885c4b73f97011d08.zip | |
[PATCH] mm: mremap correct rmap accounting
Nick Piggin points out that page accounting on MIPS multiple ZERO_PAGEs
is not maintained by its move_pte, and could lead to freeing a ZERO_PAGE.
Instead of complicating that move_pte, just forget the minor optimization
when mremapping, and change the one thing which needed it for correctness
- filemap_xip use ZERO_PAGE(0) throughout instead of according to address.
[ "There is no block device driver one could use for XIP on mips
platforms" - Carsten Otte ]
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap_xip.c | 4 | ||||
| -rw-r--r-- | mm/mremap.c | 1 |
2 files changed, 2 insertions, 3 deletions
diff --git a/mm/filemap_xip.c b/mm/filemap_xip.c index 45b3553865cf..9dd9fbb75139 100644 --- a/mm/filemap_xip.c +++ b/mm/filemap_xip.c @@ -183,7 +183,7 @@ __xip_unmap (struct address_space * mapping, address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); BUG_ON(address < vma->vm_start || address >= vma->vm_end); - page = ZERO_PAGE(address); + page = ZERO_PAGE(0); pte = page_check_address(page, mm, address, &ptl); if (pte) { /* Nuke the page table entry. */ @@ -246,7 +246,7 @@ xip_file_nopage(struct vm_area_struct * area, __xip_unmap(mapping, pgoff); } else { /* not shared and writable, use ZERO_PAGE() */ - page = ZERO_PAGE(address); + page = ZERO_PAGE(0); } out: diff --git a/mm/mremap.c b/mm/mremap.c index 9c769fa29f32..5d4bd4f95b8e 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -105,7 +105,6 @@ static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd, if (pte_none(*old_pte)) continue; pte = ptep_clear_flush(vma, old_addr, old_pte); - /* ZERO_PAGE can be dependant on virtual addr */ pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr); set_pte_at(mm, new_addr, new_pte, pte); } |