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Subject[PATCH 10/16] mm: use vm_unmapped_area() on mips architecture
Date
Update the mips arch_get_unmapped_area[_topdown] functions to make
use of vm_unmapped_area() instead of implementing a brute force search.

Signed-off-by: Michel Lespinasse <walken@google.com>

---
arch/mips/mm/mmap.c | 99 +++++++++------------------------------------------
1 files changed, 17 insertions(+), 82 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 302d779d5b0d..e4b54b233e17 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -71,6 +71,7 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
struct vm_area_struct *vma;
unsigned long addr = addr0;
int do_color_align;
+ struct vm_unmapped_area_info info;

if (unlikely(len > TASK_SIZE))
return -ENOMEM;
@@ -107,97 +108,31 @@ static unsigned long arch_get_unmapped_area_common(struct file *filp,
return addr;
}

- if (dir == UP) {
- addr = mm->mmap_base;
- if (do_color_align)
- addr = COLOUR_ALIGN(addr, pgoff);
- else
- addr = PAGE_ALIGN(addr);
+ info.length = len;
+ info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
+ info.align_offset = pgoff << PAGE_SHIFT;

- for (vma = find_vma(current->mm, addr); ; vma = vma->vm_next) {
- /* At this point: (!vma || addr < vma->vm_end). */
- if (TASK_SIZE - len < addr)
- return -ENOMEM;
- if (!vma || addr + len <= vma->vm_start)
- return addr;
- addr = vma->vm_end;
- if (do_color_align)
- addr = COLOUR_ALIGN(addr, pgoff);
- }
- } else {
- /* check if free_area_cache is useful for us */
- if (len <= mm->cached_hole_size) {
- mm->cached_hole_size = 0;
- mm->free_area_cache = mm->mmap_base;
- }
+ if (dir == DOWN) {
+ info.flags = VM_UNMAPPED_AREA_TOPDOWN;
+ info.low_limit = PAGE_SIZE;
+ info.high_limit = mm->mmap_base;
+ addr = vm_unmapped_area(&info);
+
+ if (!(addr & ~PAGE_MASK))
+ return addr;

- /*
- * either no address requested, or the mapping can't fit into
- * the requested address hole
- */
- addr = mm->free_area_cache;
- if (do_color_align) {
- unsigned long base =
- COLOUR_ALIGN_DOWN(addr - len, pgoff);
- addr = base + len;
- }
-
- /* make sure it can fit in the remaining address space */
- if (likely(addr > len)) {
- vma = find_vma(mm, addr - len);
- if (!vma || addr <= vma->vm_start) {
- /* cache the address as a hint for next time */
- return mm->free_area_cache = addr - len;
- }
- }
-
- if (unlikely(mm->mmap_base < len))
- goto bottomup;
-
- addr = mm->mmap_base - len;
- if (do_color_align)
- addr = COLOUR_ALIGN_DOWN(addr, pgoff);
-
- do {
- /*
- * Lookup failure means no vma is above this address,
- * else if new region fits below vma->vm_start,
- * return with success:
- */
- vma = find_vma(mm, addr);
- if (likely(!vma || addr + len <= vma->vm_start)) {
- /* cache the address as a hint for next time */
- return mm->free_area_cache = addr;
- }
-
- /* remember the largest hole we saw so far */
- if (addr + mm->cached_hole_size < vma->vm_start)
- mm->cached_hole_size = vma->vm_start - addr;
-
- /* try just below the current vma->vm_start */
- addr = vma->vm_start - len;
- if (do_color_align)
- addr = COLOUR_ALIGN_DOWN(addr, pgoff);
- } while (likely(len < vma->vm_start));
-
-bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
* can happen with large stack limits and large mmap()
* allocations.
*/
- mm->cached_hole_size = ~0UL;
- mm->free_area_cache = TASK_UNMAPPED_BASE;
- addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
- /*
- * Restore the topdown base:
- */
- mm->free_area_cache = mm->mmap_base;
- mm->cached_hole_size = ~0UL;
-
- return addr;
}
+
+ info.flags = 0;
+ info.low_limit = mm->mmap_base;
+ info.high_limit = TASK_SIZE;
+ return vm_unmapped_area(&info);
}

unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
--
1.7.7.3

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