From 493af578040e690f93f0fc8d9e7667ffff8155bb Mon Sep 17 00:00:00 2001
From: =?utf8?q?J=C3=B6rn=20Engel?= <joern@logfs.org>
Date: Mon, 8 Jul 2013 16:00:26 -0700
Subject: [PATCH] mmap: allow MAP_HUGETLB for hugetlbfs files v2
It is counterintuitive at best that mmap'ing a hugetlbfs file with
MAP_HUGETLB fails, while mmap'ing it without will a) succeed and b)
return huge pages.
v2: use is_file_hugepages(), as suggested by Jianguo
Signed-off-by: Joern Engel <joern@logfs.org>
Cc: Jianguo Wu <wujianguo@huawei.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/mmap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 8468ffd05bae..0718c175db8f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1358,13 +1358,14 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
if (!(flags & MAP_ANONYMOUS)) {
audit_mmap_fd(fd, flags);
- if (unlikely(flags & MAP_HUGETLB))
- return -EINVAL;
file = fget(fd);
if (!file)
goto out;
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;
} else if (flags & MAP_HUGETLB) {
struct user_struct *user = NULL;
struct hstate *hs = hstate_sizelog((flags >> MAP_HUGE_SHIFT) &
@@ -1391,6 +1392,7 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
flags &= ~(MAP_EXECUTABLE | MAP_DENYWRITE);
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
+out_fput:
if (file)
fput(file);
out:
--
2.34.1