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VM: add "vm_mmap()" helper function

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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>
This commit is contained in:
Linus Torvalds
2012-04-20 17:13:58 -07:00
parent a46ef99d80
commit 6be5ceb02e
15 changed files with 87 additions and 97 deletions
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23
include/linux/mm.h
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@@ -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);