mm, mpx: add "vm_flags_t vm_flags" arg to do_mmap_pgoff()

Add the additional "vm_flags_t vm_flags" argument to do_mmap_pgoff(),
rename it to do_mmap(), and re-introduce do_mmap_pgoff() as a simple
wrapper on top of do_mmap().  Perhaps we should update the callers of
do_mmap_pgoff() and kill it later.

This way mpx_mmap() can simply call do_mmap(vm_flags => VM_MPX) and do not
play with vm internals.

After this change mmap_region() has a single user outside of mmap.c,
arch/tile/mm/elf.c:arch_setup_additional_pages().  It would be nice to
change arch/tile/ and unexport mmap_region().

[kirill@shutemov.name: fix build]
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Tested-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 31 insertions, 61 deletions

diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index db1b0bc5017c..134948b0926f 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -42,58 +42,21 @@ static inline unsigned long mpx_bt_size_bytes(struct mm_struct *mm)
  */
 static unsigned long mpx_mmap(unsigned long len)
 {
-        unsigned long ret;
-        unsigned long addr, pgoff;
         struct mm_struct *mm = current->mm;
-        vm_flags_t vm_flags;
-        struct vm_area_struct *vma;
+        unsigned long addr, populate;
 
         /* Only bounds table can be allocated here */
         if (len != mpx_bt_size_bytes(mm))
                 return -EINVAL;
 
         down_write(&mm->mmap_sem);
-
-        /* Too many mappings? */
-        if (mm->map_count > sysctl_max_map_count) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
-        /* Obtain the address to map to. we verify (or select) it and ensure
-         * that it represents a valid section of the address space.
-         */
-        addr = get_unmapped_area(NULL, 0, len, 0, MAP_ANONYMOUS | MAP_PRIVATE);
-        if (addr & ~PAGE_MASK) {
-                ret = addr;
-                goto out;
-        }
-
-        vm_flags = VM_READ | VM_WRITE | VM_MPX |
-                        mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
-
-        /* Set pgoff according to addr for anon_vma */
-        pgoff = addr >> PAGE_SHIFT;
-
-        ret = mmap_region(NULL, addr, len, vm_flags, pgoff);
-        if (IS_ERR_VALUE(ret))
-                goto out;
-
-        vma = find_vma(mm, ret);
-        if (!vma) {
-                ret = -ENOMEM;
-                goto out;
-        }
-
-        if (vm_flags & VM_LOCKED) {
-                up_write(&mm->mmap_sem);
-                mm_populate(ret, len);
-                return ret;
-        }
-
-out:
+        addr = do_mmap(NULL, 0, len, PROT_READ | PROT_WRITE,
+                        MAP_ANONYMOUS | MAP_PRIVATE, VM_MPX, 0, &populate);
         up_write(&mm->mmap_sem);
-        return ret;
+        if (populate)
+                mm_populate(addr, populate);
+
+        return addr;
 }
 
 enum reg_type {
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f25a957bf0ab..fda728e3c27d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1873,11 +1873,19 @@ extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned lo
 
 extern unsigned long mmap_region(struct file *file, unsigned long addr,
         unsigned long len, vm_flags_t vm_flags, unsigned long pgoff);
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+extern unsigned long do_mmap(struct file *file, unsigned long addr,
         unsigned long len, unsigned long prot, unsigned long flags,
-        unsigned long pgoff, unsigned long *populate);
+        vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
 
+static inline unsigned long
+do_mmap_pgoff(struct file *file, unsigned long addr,
+        unsigned long len, unsigned long prot, unsigned long flags,
+        unsigned long pgoff, unsigned long *populate)
+{
+        return do_mmap(file, addr, len, prot, flags, 0, pgoff, populate);
+}
+
 #ifdef CONFIG_MMU
 extern int __mm_populate(unsigned long addr, unsigned long len,
                          int ignore_errors);
diff --git a/mm/mmap.c b/mm/mmap.c
index b6be3249f0a9..c739d6db7193 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1260,14 +1260,12 @@ static inline int mlock_future_check(struct mm_struct *mm,
 /*
  * The caller must hold down_write(&current->mm->mmap_sem).
  */
-
-unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
+unsigned long do_mmap(struct file *file, unsigned long addr,
                         unsigned long len, unsigned long prot,
-                        unsigned long flags, unsigned long pgoff,
-                        unsigned long *populate)
+                        unsigned long flags, vm_flags_t vm_flags,
+                        unsigned long pgoff, unsigned long *populate)
 {
         struct mm_struct *mm = current->mm;
-        vm_flags_t vm_flags;
 
         *populate = 0;
 
@@ -1311,7 +1309,7 @@ unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
          * to. we assume access permissions have been handled by the open
          * of the memory object, so we don't do any here.
          */
-        vm_flags = calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
+        vm_flags |= calc_vm_prot_bits(prot) | calc_vm_flag_bits(flags) |
                         mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
 
         if (flags & MAP_LOCKED)
diff --git a/mm/nommu.c b/mm/nommu.c
index 1cc0709fcaa5..ab14a2014dea 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -1233,18 +1233,19 @@ enomem:
 /*
  * handle mapping creation for uClinux
  */
-unsigned long do_mmap_pgoff(struct file *file,
-                            unsigned long addr,
-                            unsigned long len,
-                            unsigned long prot,
-                            unsigned long flags,
-                            unsigned long pgoff,
-                            unsigned long *populate)
+unsigned long do_mmap(struct file *file,
+                        unsigned long addr,
+                        unsigned long len,
+                        unsigned long prot,
+                        unsigned long flags,
+                        vm_flags_t vm_flags,
+                        unsigned long pgoff,
+                        unsigned long *populate)
 {
         struct vm_area_struct *vma;
         struct vm_region *region;
         struct rb_node *rb;
-        unsigned long capabilities, vm_flags, result;
+        unsigned long capabilities, result;
         int ret;
 
         *populate = 0;
@@ -1262,7 +1263,7 @@ unsigned long do_mmap_pgoff(struct file *file,
 
         /* we've determined that we can make the mapping, now translate what we
          * now know into VMA flags */
-        vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+        vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
 
         /* we're going to need to record the mapping */
         region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);