hugetlbfs: fix mmap failure in unaligned size request

The current kernel returns -EINVAL unless a given mmap length is
"almost" hugepage aligned.  This is because in sys_mmap_pgoff() the
given length is passed to vm_mmap_pgoff() as it is without being aligned
with hugepage boundary.

This is a regression introduced in commit 40716e29243d ("hugetlbfs: fix
alignment of huge page requests"), where alignment code is pushed into
hugetlb_file_setup() and the variable len in caller side is not changed.

To fix this, this patch partially reverts that commit, and adds
alignment code in caller side.  And it also introduces hstate_sizelog()
in order to get proper hstate to specified hugepage size.

Addresses https://bugzilla.kernel.org/show_bug.cgi?id=56881

[akpm@linux-foundation.org: fix warning when CONFIG_HUGETLB_PAGE=n]
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: <iceman_dvd@yahoo.com>
Cc: Steven Truelove <steven.truelove@utoronto.ca>
Cc: Jianguo Wu <wujianguo@huawei.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 1 deletions

diff --git a/mm/mmap.c b/mm/mmap.c
index da3e9c04bf37..1ae21d645c68 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1363,15 +1363,20 @@ SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
                 file = fget(fd);
                 if (!file)
                         goto out;
+                if (is_file_hugepages(file))
+                        len = ALIGN(len, huge_page_size(hstate_file(file)));
         } else if (flags & MAP_HUGETLB) {
                 struct user_struct *user = NULL;
+
+                len = ALIGN(len, huge_page_size(hstate_sizelog(
+                        (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK)));
                 /*
                  * VM_NORESERVE is used because the reservations will be
                  * taken when vm_ops->mmap() is called
                  * A dummy user value is used because we are not locking
                  * memory so no accounting is necessary
                  */
-                file = hugetlb_file_setup(HUGETLB_ANON_FILE, addr, len,
+                file = hugetlb_file_setup(HUGETLB_ANON_FILE, len,
                                 VM_NORESERVE,
                                 &user, HUGETLB_ANONHUGE_INODE,
                                 (flags >> MAP_HUGE_SHIFT) & MAP_HUGE_MASK);