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mm: prepare VM_DONTDUMP for using in drivers

Rename VM_NODUMP into VM_DONTDUMP: this name matches other negative flags:
VM_DONTEXPAND, VM_DONTCOPY.  Currently this flag used only for
sys_madvise.  The next patch will use it for replacing the outdated flag
VM_RESERVED.

Also forbid madvise(MADV_DODUMP) for special kernel mappings VM_SPECIAL
(VM_IO | VM_DONTEXPAND | VM_RESERVED | VM_PFNMAP)

Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Carsten Otte <cotte@de.ibm.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Eric Paris <eparis@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Morris <james.l.morris@oracle.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Kentaro Takeda <takedakn@nttdata.co.jp>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Nick Piggin <npiggin@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Venkatesh Pallipadi <venki@google.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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1 parent e9714ac commit 0103bd16fb90bc741c7a03fd1ea4e8a505abad23 @koct9i koct9i committed with torvalds Oct 8, 2012
Showing with 8 additions and 4 deletions.
  1. +1 −1 fs/binfmt_elf.c
  2. +1 −1 include/linux/mm.h
  3. +6 −2 mm/madvise.c
View
2 fs/binfmt_elf.c
@@ -1123,7 +1123,7 @@ static unsigned long vma_dump_size(struct vm_area_struct *vma,
if (always_dump_vma(vma))
goto whole;
- if (vma->vm_flags & VM_NODUMP)
+ if (vma->vm_flags & VM_DONTDUMP)
return 0;
/* Hugetlb memory check */
View
2 include/linux/mm.h
@@ -102,7 +102,7 @@ extern unsigned int kobjsize(const void *objp);
#define VM_HUGETLB 0x00400000 /* Huge TLB Page VM */
#define VM_NONLINEAR 0x00800000 /* Is non-linear (remap_file_pages) */
#define VM_ARCH_1 0x01000000 /* Architecture-specific flag */
-#define VM_NODUMP 0x04000000 /* Do not include in the core dump */
+#define VM_DONTDUMP 0x04000000 /* Do not include in the core dump */
#define VM_MIXEDMAP 0x10000000 /* Can contain "struct page" and pure PFN pages */
#define VM_HUGEPAGE 0x20000000 /* MADV_HUGEPAGE marked this vma */
View
8 mm/madvise.c
@@ -69,10 +69,14 @@ static long madvise_behavior(struct vm_area_struct * vma,
new_flags &= ~VM_DONTCOPY;
break;
case MADV_DONTDUMP:
- new_flags |= VM_NODUMP;
+ new_flags |= VM_DONTDUMP;
break;
case MADV_DODUMP:
- new_flags &= ~VM_NODUMP;
+ if (new_flags & VM_SPECIAL) {
+ error = -EINVAL;
+ goto out;
+ }
+ new_flags &= ~VM_DONTDUMP;
break;
case MADV_MERGEABLE:
case MADV_UNMERGEABLE:

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