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mm: make the vma list be doubly linked

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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>
This commit is contained in:
Linus Torvalds
2010-08-20 16:24:55 -07:00
parent 36423a5ed5
commit 297c5eee37
4 changed files with 28 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

21
mm/mmap.c
View File

@@ -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;

7
mm/nommu.c
View File

@@ -604,7 +604,7 @@ static void protect_vma(struct vm_area_struct *vma, unsigned long flags)
*/
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
{
struct vm_area_struct *pvma, **pp;
struct vm_area_struct *pvma, **pp, *next;
struct address_space *mapping;
struct rb_node **p, *parent;
@@ -664,8 +664,11 @@ static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
break;
}
vma->vm_next = *pp;
next = *pp;
*pp = vma;
vma->vm_next = next;
if (next)
next->vm_prev = vma;
}
/*