[PATCH 1/3] mm: move argument checkers of mmap_pgoff() to separated routine

[Yury Norov]

Signed-off-by: Yury Norov <yno...@caviumnetworks.com>
---
 mm/mmap.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 1af87c1..fc1c943 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1455,12 +1455,12 @@ unsigned long do_mmap(struct file *file, unsigned long 
addr,
        return addr;
 }
 
-SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
-               unsigned long, prot, unsigned long, flags,
-               unsigned long, fd, unsigned long, pgoff)
+static int mmap_pgoff_prepare(struct file **f, unsigned long *l,
+               unsigned long *fl, unsigned long fd)
 {
-       struct file *file = NULL;
-       unsigned long retval;
+       struct file *file = *f;
+       unsigned long flags = *fl;
+       unsigned long len = *l;
 
        if (!(flags & MAP_ANONYMOUS)) {
                audit_mmap_fd(fd, flags);
@@ -1469,9 +1469,10 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, 
unsigned long, len,
                        return -EBADF;
                if (is_file_hugepages(file))
                        len = ALIGN(len, huge_page_size(hstate_file(file)));
-               retval = -EINVAL;
-               if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file)))
-                       goto out_fput;
+               if (unlikely(flags & MAP_HUGETLB && !is_file_hugepages(file))) {
+                       fput(file);
+                       return -EINVAL;
+               }
        } else if (flags & MAP_HUGETLB) {
                struct user_struct *user = NULL;
                struct hstate *hs;
@@ -1497,8 +1498,23 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, 
unsigned long, len,
 
        flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
 
+       *f = file;
+       *l = len;
+       *fl = flags;
+       return 0;
+}
+
+SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
+               unsigned long, prot, unsigned long, flags,
+               unsigned long, fd, unsigned long, pgoff)
+{
+       struct file *file = NULL;
+       unsigned long retval;
+       int err = mmap_pgoff_prepare(&file, &len, &flags, fd);
+       if (err)
+               return err;
+
        retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
-out_fput:
        if (file)
                fput(file);
        return retval;
-- 
2.7.4