diff options
-rw-r--r-- | mm/mremap.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/mm/mremap.c b/mm/mremap.c index 5f346178f16f..90e422c9f410 100644 --- a/mm/mremap.c +++ b/mm/mremap.c | |||
@@ -366,6 +366,17 @@ out: | |||
366 | return ret; | 366 | return ret; |
367 | } | 367 | } |
368 | 368 | ||
369 | static int vma_expandable(struct vm_area_struct *vma, unsigned long delta) | ||
370 | { | ||
371 | unsigned long max_addr = TASK_SIZE; | ||
372 | if (vma->vm_next) | ||
373 | max_addr = vma->vm_next->vm_start; | ||
374 | if (max_addr - vma->vm_end < delta) | ||
375 | return 0; | ||
376 | /* we need to do arch-specific checks here */ | ||
377 | return 1; | ||
378 | } | ||
379 | |||
369 | /* | 380 | /* |
370 | * Expand (or shrink) an existing mapping, potentially moving it at the | 381 | * Expand (or shrink) an existing mapping, potentially moving it at the |
371 | * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) | 382 | * same time (controlled by the MREMAP_MAYMOVE flag and available VM space) |
@@ -430,11 +441,8 @@ unsigned long do_mremap(unsigned long addr, | |||
430 | /* old_len exactly to the end of the area.. | 441 | /* old_len exactly to the end of the area.. |
431 | */ | 442 | */ |
432 | if (old_len == vma->vm_end - addr) { | 443 | if (old_len == vma->vm_end - addr) { |
433 | unsigned long max_addr = TASK_SIZE; | ||
434 | if (vma->vm_next) | ||
435 | max_addr = vma->vm_next->vm_start; | ||
436 | /* can we just expand the current mapping? */ | 444 | /* can we just expand the current mapping? */ |
437 | if (max_addr - addr >= new_len) { | 445 | if (vma_expandable(vma, new_len - old_len)) { |
438 | int pages = (new_len - old_len) >> PAGE_SHIFT; | 446 | int pages = (new_len - old_len) >> PAGE_SHIFT; |
439 | 447 | ||
440 | vma_adjust(vma, vma->vm_start, | 448 | vma_adjust(vma, vma->vm_start, |