mm: kill vma flag VM_RESERVED and mm->reserved_vm counter

A long time ago, in v2.4, VM_RESERVED kept swapout process off VMA,
currently it lost original meaning but still has some effects:

 | effect                 | alternative flags
-+------------------------+---------------------------------------------
1| account as reserved_vm | VM_IO
2| skip in core dump      | VM_IO, VM_DONTDUMP
3| do not merge or expand | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP
4| do not mlock           | VM_IO, VM_DONTEXPAND, VM_HUGETLB, VM_PFNMAP

This patch removes reserved_vm counter from mm_struct.  Seems like nobody
cares about it, it does not exported into userspace directly, it only
reduces total_vm showed in proc.

Thus VM_RESERVED can be replaced with VM_IO or pair VM_DONTEXPAND | VM_DONTDUMP.

remap_pfn_range() and io_remap_pfn_range() set VM_IO|VM_DONTEXPAND|VM_DONTDUMP.
remap_vmalloc_range() set VM_DONTEXPAND | VM_DONTDUMP.

[akpm@linux-foundation.org: drivers/vfio/pci/vfio_pci.c fixup]
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>

3 files changed, 3 insertions, 3 deletions

diff --git a/drivers/char/mbcs.c b/drivers/char/mbcs.c
index 0c7d340b9ab9..f74e892711dd 100644
--- a/drivers/char/mbcs.c
+++ b/drivers/char/mbcs.c
@@ -507,7 +507,7 @@ static int mbcs_gscr_mmap(struct file *fp, struct vm_area_struct *vma)
 
         vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 
-        /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
+        /* Remap-pfn-range will mark the range VM_IO */
         if (remap_pfn_range(vma,
                             vma->vm_start,
                             __pa(soft->gscr_addr) >> PAGE_SHIFT,
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index e5eedfa24c91..0537903c985b 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -322,7 +322,7 @@ static int mmap_mem(struct file *file, struct vm_area_struct *vma)
 
         vma->vm_ops = &mmap_mem_ops;
 
-        /* Remap-pfn-range will mark the range VM_IO and VM_RESERVED */
+        /* Remap-pfn-range will mark the range VM_IO */
         if (remap_pfn_range(vma,
                             vma->vm_start,
                             vma->vm_pgoff,
diff --git a/drivers/char/mspec.c b/drivers/char/mspec.c
index 845f97fd1832..e1f60f968fdd 100644
--- a/drivers/char/mspec.c
+++ b/drivers/char/mspec.c
@@ -286,7 +286,7 @@ mspec_mmap(struct file *file, struct vm_area_struct *vma,
         atomic_set(&vdata->refcnt, 1);
         vma->vm_private_data = vdata;
 
-        vma->vm_flags |= (VM_IO | VM_RESERVED | VM_PFNMAP | VM_DONTEXPAND);
+        vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
         if (vdata->type == MSPEC_FETCHOP || vdata->type == MSPEC_UNCACHED)
                 vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
         vma->vm_ops = &mspec_vm_ops;