diff options
Diffstat (limited to 'mm/madvise.c')
| -rw-r--r-- | mm/madvise.c | 35 |
1 files changed, 35 insertions, 0 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 2b7cf04..ae0ae3e 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -140,6 +140,36 @@ static long madvise_dontneed(struct vm_area_struct * vma, return 0; } +/* + * Application wants to free up the pages and associated backing store. + * This is effectively punching a hole into the middle of a file. + * + * NOTE: Currently, only shmfs/tmpfs is supported for this operation. + * Other filesystems return -ENOSYS. + */ +static long madvise_remove(struct vm_area_struct *vma, + unsigned long start, unsigned long end) +{ + struct address_space *mapping; + loff_t offset, endoff; + + if (vma->vm_flags & (VM_LOCKED|VM_NONLINEAR|VM_HUGETLB)) + return -EINVAL; + + if (!vma->vm_file || !vma->vm_file->f_mapping + || !vma->vm_file->f_mapping->host) { + return -EINVAL; + } + + mapping = vma->vm_file->f_mapping; + + offset = (loff_t)(start - vma->vm_start) + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + endoff = (loff_t)(end - vma->vm_start - 1) + + ((loff_t)vma->vm_pgoff << PAGE_SHIFT); + return vmtruncate_range(mapping->host, offset, endoff); +} + static long madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, unsigned long start, unsigned long end, int behavior) @@ -152,6 +182,9 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, case MADV_RANDOM: error = madvise_behavior(vma, prev, start, end, behavior); break; + case MADV_REMOVE: + error = madvise_remove(vma, start, end); + break; case MADV_WILLNEED: error = madvise_willneed(vma, prev, start, end); @@ -190,6 +223,8 @@ madvise_vma(struct vm_area_struct *vma, struct vm_area_struct **prev, * some pages ahead. * MADV_DONTNEED - the application is finished with the given range, * so the kernel can free resources associated with it. + * MADV_REMOVE - the application wants to free up the given range of + * pages and associated backing store. * * return values: * zero - success |