VM: add "vm_mmap()" helper function

This continues the theme started with vm_brk() and vm_munmap():
vm_mmap() does the same thing as do_mmap(), but additionally does the
required VM locking.

This uninlines (and rewrites it to be clearer) do_mmap(), which sadly
duplicates it in mm/mmap.c and mm/nommu.c.  But that way we don't have
to export our internal do_mmap_pgoff() function.

Some day we hopefully don't have to export do_mmap() either, if all
modular users can become the simpler vm_mmap() instead.  We're actually
very close to that already, with the notable exception of the (broken)
use in i810, and a couple of stragglers in binfmt_elf.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 17 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index cb61950a3aa1..86a692c3b238 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1393,31 +1393,20 @@ extern int install_special_mapping(struct mm_struct *mm,
 
 extern unsigned long get_unmapped_area(struct file *, unsigned long, unsigned long, unsigned long, unsigned long);
 
-extern unsigned long do_mmap_pgoff(struct file *file, unsigned long addr,
-        unsigned long len, unsigned long prot,
-        unsigned long flag, unsigned long pgoff);
 extern unsigned long mmap_region(struct file *file, unsigned long addr,
         unsigned long len, unsigned long flags,
         vm_flags_t vm_flags, unsigned long pgoff);
-
-static inline unsigned long do_mmap(struct file *file, unsigned long addr,
-        unsigned long len, unsigned long prot,
-        unsigned long flag, unsigned long offset)
-{
-        unsigned long ret = -EINVAL;
-        if ((offset + PAGE_ALIGN(len)) < offset)
-                goto out;
-        if (!(offset & ~PAGE_MASK))
-                ret = do_mmap_pgoff(file, addr, len, prot, flag, offset >> PAGE_SHIFT);
-out:
-        return ret;
-}
-
+extern unsigned long do_mmap(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
 extern int do_munmap(struct mm_struct *, unsigned long, size_t);
 
 /* These take the mm semaphore themselves */
 extern unsigned long vm_brk(unsigned long, unsigned long);
 extern int vm_munmap(struct mm_struct *, unsigned long, size_t);
+extern unsigned long vm_mmap(struct file *, unsigned long,
+        unsigned long, unsigned long,
+        unsigned long, unsigned long);
 
 /* truncate.c */
 extern void truncate_inode_pages(struct address_space *, loff_t);