[PATCH] mm: unmap_vmas with inner ptlock
Remove the page_table_lock from around the calls to unmap_vmas, and replace
the pte_offset_map in zap_pte_range by pte_offset_map_lock: all callers are
now safe to descend without page_table_lock.
Don't attempt fancy locking for hugepages, just take page_table_lock in
unmap_hugepage_range. Which makes zap_hugepage_range, and the hugetlb test in
zap_page_range, redundant: unmap_vmas calls unmap_hugepage_range anyway. Nor
does unmap_vmas have much use for its mm arg now.
The tlb_start_vma and tlb_end_vma in unmap_page_range are now called without
page_table_lock: if they're implemented at all, they typically come down to
flush_cache_range (usually done outside page_table_lock) and flush_tlb_range
(which we already audited for the mprotect case).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ea0826f..f29b7dc 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -314,6 +314,8 @@
BUG_ON(start & ~HPAGE_MASK);
BUG_ON(end & ~HPAGE_MASK);
+ spin_lock(&mm->page_table_lock);
+
/* Update high watermark before we lower rss */
update_hiwater_rss(mm);
@@ -333,17 +335,9 @@
put_page(page);
add_mm_counter(mm, file_rss, (int) -(HPAGE_SIZE / PAGE_SIZE));
}
- flush_tlb_range(vma, start, end);
-}
-void zap_hugepage_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long length)
-{
- struct mm_struct *mm = vma->vm_mm;
-
- spin_lock(&mm->page_table_lock);
- unmap_hugepage_range(vma, start, start + length);
spin_unlock(&mm->page_table_lock);
+ flush_tlb_range(vma, start, end);
}
int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)