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

Yury Norov
2016-12-11T12:57:52Z

Signed-off-by: Yury Norov <ynorov@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