diff options
| -rw-r--r-- | mm/mmap.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/mm/mmap.c b/mm/mmap.c index 02c09f33df8..d9c77b2dbe9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -1198,8 +1198,20 @@ munmap_back: goto free_vma; } - if (vma_wants_writenotify(vma)) + if (vma_wants_writenotify(vma)) { + pgprot_t pprot = vma->vm_page_prot; + + /* Can vma->vm_page_prot have changed?? + * + * Answer: Yes, drivers may have changed it in their + * f_op->mmap method. + * + * Ensures that vmas marked as uncached stay that way. + */ vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED); + if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot))) + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + } vma_link(mm, vma, prev, rb_link, rb_parent); file = vma->vm_file; |