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authorLinus Torvalds <torvalds@linux-foundation.org>2010-08-20 16:24:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-08-21 08:49:21 -0700
commit297c5eee372478fc32fec5fe8eed711eedb13f3d (patch)
tree18415eae0833ff4767943f985900524d6b1d73f1 /mm/mmap.c
parent36423a5ed5e4ea95ceedb68fad52965033e11639 (diff)
downloadlwn-297c5eee372478fc32fec5fe8eed711eedb13f3d.tar.gz
lwn-297c5eee372478fc32fec5fe8eed711eedb13f3d.zip
mm: make the vma list be doubly linked
It's a really simple list, and several of the users want to go backwards in it to find the previous vma. So rather than have to look up the previous entry with 'find_vma_prev()' or something similar, just make it doubly linked instead. Tested-by: Ian Campbell <ijc@hellion.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/mmap.c')
-rw-r--r--mm/mmap.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/mm/mmap.c b/mm/mmap.c
index 31003338b978..331e51af38c9 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -388,17 +388,23 @@ static inline void
__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node *rb_parent)
{
+ struct vm_area_struct *next;
+
+ vma->vm_prev = prev;
if (prev) {
- vma->vm_next = prev->vm_next;
+ next = prev->vm_next;
prev->vm_next = vma;
} else {
mm->mmap = vma;
if (rb_parent)
- vma->vm_next = rb_entry(rb_parent,
+ next = rb_entry(rb_parent,
struct vm_area_struct, vm_rb);
else
- vma->vm_next = NULL;
+ next = NULL;
}
+ vma->vm_next = next;
+ if (next)
+ next->vm_prev = vma;
}
void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -483,7 +489,11 @@ static inline void
__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev)
{
- prev->vm_next = vma->vm_next;
+ struct vm_area_struct *next = vma->vm_next;
+
+ prev->vm_next = next;
+ if (next)
+ next->vm_prev = prev;
rb_erase(&vma->vm_rb, &mm->mm_rb);
if (mm->mmap_cache == vma)
mm->mmap_cache = prev;
@@ -1915,6 +1925,7 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
unsigned long addr;
insertion_point = (prev ? &prev->vm_next : &mm->mmap);
+ vma->vm_prev = NULL;
do {
rb_erase(&vma->vm_rb, &mm->mm_rb);
mm->map_count--;
@@ -1922,6 +1933,8 @@ detach_vmas_to_be_unmapped(struct mm_struct *mm, struct vm_area_struct *vma,
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
*insertion_point = vma;
+ if (vma)
+ vma->vm_prev = prev;
tail_vma->vm_next = NULL;
if (mm->unmap_area == arch_unmap_area)
addr = prev ? prev->vm_end : mm->mmap_base;