[PATCH] unpaged: private write VM_RESERVED
The PageReserved removal in 2.6.15-rc1 issued a "deprecated" message when you
tried to mmap or mprotect MAP_PRIVATE PROT_WRITE a VM_RESERVED, and failed
with -EACCES: because do_wp_page lacks the refinement to COW pages in those
areas, nor do we expect to find anonymous pages in them; and it seemed just
bloat to add code for handling such a peculiar case. But immediately it
caused vbetool and ddcprobe (using lrmi) to fail.
So revert the "deprecated" messages, letting mmap and mprotect succeed. But
leave do_wp_page's BUG_ON(vma->vm_flags & VM_RESERVED) in place until we've
added the code to do it right: so this particular patch is only good if the
app doesn't really need to write to that private area.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index 4f8def0..11ca592 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1076,17 +1076,6 @@
error = file->f_op->mmap(file, vma);
if (error)
goto unmap_and_free_vma;
- if ((vma->vm_flags & (VM_SHARED | VM_WRITE | VM_RESERVED))
- == (VM_WRITE | VM_RESERVED)) {
- printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
- "PROT_WRITE mmap of VM_RESERVED memory, which "
- "is deprecated. Please report this to "
- "linux-kernel@vger.kernel.org\n",current->comm);
- if (vma->vm_ops && vma->vm_ops->close)
- vma->vm_ops->close(vma);
- error = -EACCES;
- goto unmap_and_free_vma;
- }
} else if (vm_flags & VM_SHARED) {
error = shmem_zero_setup(vma);
if (error)
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 17a2b52..653b857 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -124,14 +124,6 @@
* a MAP_NORESERVE private mapping to writable will now reserve.
*/
if (newflags & VM_WRITE) {
- if (oldflags & VM_RESERVED) {
- BUG_ON(oldflags & VM_WRITE);
- printk(KERN_WARNING "program %s is using MAP_PRIVATE, "
- "PROT_WRITE mprotect of VM_RESERVED memory, "
- "which is deprecated. Please report this to "
- "linux-kernel@vger.kernel.org\n",current->comm);
- return -EACCES;
- }
if (!(oldflags & (VM_ACCOUNT|VM_WRITE|VM_SHARED|VM_HUGETLB))) {
charged = nrpages;
if (security_vm_enough_memory(charged))