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  The next patch will use it for replacing the outdated flag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 <[email protected]>
Cc: Alexander Viro <[email protected]>
Cc: Carsten Otte <[email protected]>
Cc: Chris Metcalf <[email protected]>
Cc: Cyrill Gorcunov <[email protected]>
Cc: Eric Paris <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Morris <[email protected]>
Cc: Jason Baron <[email protected]>
Cc: Kentaro Takeda <[email protected]>
Cc: Matt Helsley <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Robert Richter <[email protected]>
Cc: Suresh Siddha <[email protected]>
Cc: Tetsuo Handa <[email protected]>
Cc: Venkatesh Pallipadi <[email protected]>
Acked-by: Linus Torvalds <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 28a64e76952788146d24b4fe0e0069918c0b9584..2b72d26e2e4b5da6809d5dc9fad2783aa2d99475 100644 (file)
--- a/fs/binfmt_elf.c
+++ b/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 */

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 25ef49c1f2bd553f00f4357d6c515baaebf9623a..dc08d558e058d8a5e2ea94564edd2da42add2b76 100644 (file)
--- a/include/linux/mm.h
+++ b/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 */

diff --git a/mm/madvise.c b/mm/madvise.c
index 14d260fa0d17939a2279c244df91789cd30720e4..03dfa5c7adb3c41acdf672b6504516073866c996 100644 (file)
--- a/mm/madvise.c
+++ b/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: