From 508034a32b819a2d40aa7ac0dbc8cd2e044c2de6 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:30 -0700 Subject: [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 Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mmap.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'mm/mmap.c') diff --git a/mm/mmap.c b/mm/mmap.c index fa35323a3c5..5ecc2cf3e1d 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1673,9 +1673,7 @@ static void unmap_region(struct mm_struct *mm, lru_add_drain(); tlb = tlb_gather_mmu(mm, 0); update_hiwater_rss(mm); - spin_lock(&mm->page_table_lock); - unmap_vmas(&tlb, mm, vma, start, end, &nr_accounted, NULL); - spin_unlock(&mm->page_table_lock); + unmap_vmas(&tlb, vma, start, end, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); free_pgtables(&tlb, vma, prev? prev->vm_end: FIRST_USER_ADDRESS, next? next->vm_start: 0); @@ -1958,9 +1956,7 @@ void exit_mmap(struct mm_struct *mm) tlb = tlb_gather_mmu(mm, 1); /* Don't update_hiwater_rss(mm) here, do_exit already did */ /* Use -1 here to ensure all VMAs in the mm are unmapped */ - spin_lock(&mm->page_table_lock); - end = unmap_vmas(&tlb, mm, vma, 0, -1, &nr_accounted, NULL); - spin_unlock(&mm->page_table_lock); + end = unmap_vmas(&tlb, vma, 0, -1, &nr_accounted, NULL); vm_unacct_memory(nr_accounted); free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); tlb_finish_mmu(tlb, 0, end); -- cgit v1.2.3-18-g5258