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[PATCH] mm: unmap_vmas with inner ptlock

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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>
This commit is contained in:
Hugh Dickins
2005-10-29 18:16:30 -07:00
committed by Linus Torvalds
parent 8f4f8c164c
commit 508034a32b
6 changed files with 21 additions and 54 deletions
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10
fs/hugetlbfs/inode.c
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@@ -92,7 +92,7 @@ out:
}
/*
* Called under down_write(mmap_sem), page_table_lock is not held
* Called under down_write(mmap_sem).
*/
#ifdef HAVE_ARCH_HUGETLB_UNMAPPED_AREA
@@ -308,7 +308,6 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
vma_prio_tree_foreach(vma, &iter, root, h_pgoff, ULONG_MAX) {
unsigned long h_vm_pgoff;
unsigned long v_length;
unsigned long v_offset;
h_vm_pgoff = vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT);
@@ -319,11 +318,8 @@ hugetlb_vmtruncate_list(struct prio_tree_root *root, unsigned long h_pgoff)
if (h_vm_pgoff >= h_pgoff)
v_offset = 0;
v_length = vma->vm_end - vma->vm_start;
zap_hugepage_range(vma,
vma->vm_start + v_offset,
v_length - v_offset);
unmap_hugepage_range(vma,
vma->vm_start + v_offset, vma->vm_end);
}
}