Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
+28
-9
+1
-1
include/linux/mm_types.h
+1
-1
include/linux/mm_types.h
···
134
134
within vm_mm. */
135
135
136
136
/* linked list of VM areas per task, sorted by address */
137
-
struct vm_area_struct *vm_next;
137
+
struct vm_area_struct *vm_next, *vm_prev;
138
138
139
139
pgprot_t vm_page_prot; /* Access permissions of this VMA. */
140
140
unsigned long vm_flags; /* Flags, see mm.h. */
+5
-2
kernel/fork.c
+5
-2
kernel/fork.c
···
300
300
#ifdef CONFIG_MMU
301
301
static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm)
302
302
{
303
-
struct vm_area_struct *mpnt, *tmp, **pprev;
303
+
struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
304
304
struct rb_node **rb_link, *rb_parent;
305
305
int retval;
306
306
unsigned long charge;
···
328
328
if (retval)
329
329
goto out;
330
330
331
+
prev = NULL;
331
332
for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
332
333
struct file *file;
333
334
···
360
359
goto fail_nomem_anon_vma_fork;
361
360
tmp->vm_flags &= ~VM_LOCKED;
362
361
tmp->vm_mm = mm;
363
-
tmp->vm_next = NULL;
362
+
tmp->vm_next = tmp->vm_prev = NULL;
364
363
file = tmp->vm_file;
365
364
if (file) {
366
365
struct inode *inode = file->f_path.dentry->d_inode;
···
393
392
*/
394
393
*pprev = tmp;
395
394
pprev = &tmp->vm_next;
395
+
tmp->vm_prev = prev;
396
+
prev = tmp;
396
397
397
398
__vma_link_rb(mm, tmp, rb_link, rb_parent);
398
399
rb_link = &tmp->vm_rb.rb_right;
+17
-4
mm/mmap.c
+17
-4
mm/mmap.c
···
388
388
__vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
389
389
struct vm_area_struct *prev, struct rb_node *rb_parent)
390
390
{
391
+
struct vm_area_struct *next;
392
+
393
+
vma->vm_prev = prev;
391
394
if (prev) {
392
-
vma->vm_next = prev->vm_next;
395
+
next = prev->vm_next;
393
396
prev->vm_next = vma;
394
397
} else {
395
398
mm->mmap = vma;
396
399
if (rb_parent)
397
-
vma->vm_next = rb_entry(rb_parent,
400
+
next = rb_entry(rb_parent,
398
401
struct vm_area_struct, vm_rb);
399
402
else
400
-
vma->vm_next = NULL;
403
+
next = NULL;
401
404
}
405
+
vma->vm_next = next;
406
+
if (next)
407
+
next->vm_prev = vma;
402
408
}
403
409
404
410
void __vma_link_rb(struct mm_struct *mm, struct vm_area_struct *vma,
···
489
483
__vma_unlink(struct mm_struct *mm, struct vm_area_struct *vma,
490
484
struct vm_area_struct *prev)
491
485
{
492
-
prev->vm_next = vma->vm_next;
486
+
struct vm_area_struct *next = vma->vm_next;
487
+
488
+
prev->vm_next = next;
489
+
if (next)
490
+
next->vm_prev = prev;
493
491
rb_erase(&vma->vm_rb, &mm->mm_rb);
494
492
if (mm->mmap_cache == vma)
495
493
mm->mmap_cache = prev;
···
1925
1915
unsigned long addr;
1926
1916
1927
1917
insertion_point = (prev ? &prev->vm_next : &mm->mmap);
1918
+
vma->vm_prev = NULL;
1928
1919
do {
1929
1920
rb_erase(&vma->vm_rb, &mm->mm_rb);
1930
1921
mm->map_count--;
···
1933
1922
vma = vma->vm_next;
1934
1923
} while (vma && vma->vm_start < end);
1935
1924
*insertion_point = vma;
1925
+
if (vma)
1926
+
vma->vm_prev = prev;
1936
1927
tail_vma->vm_next = NULL;
1937
1928
if (mm->unmap_area == arch_unmap_area)
1938
1929
addr = prev ? prev->vm_end : mm->mmap_base;
+5
-2
mm/nommu.c
+5
-2
mm/nommu.c
···
604
604
*/
605
605
static void add_vma_to_mm(struct mm_struct *mm, struct vm_area_struct *vma)
606
606
{
607
-
struct vm_area_struct *pvma, **pp;
607
+
struct vm_area_struct *pvma, **pp, *next;
608
608
struct address_space *mapping;
609
609
struct rb_node **p, *parent;
610
610
···
664
664
break;
665
665
}
666
666
667
-
vma->vm_next = *pp;
667
+
next = *pp;
668
668
*pp = vma;
669
+
vma->vm_next = next;
670
+
if (next)
671
+
next->vm_prev = vma;
669
672
}
670
673
671
674
/*