On 11/12/18 8:14 AM, Dan Williams wrote:
On Mon, Nov 12, 2018 at 7:45 AM Keith Busch <keith.busch@xxxxxxxxx> wrote:
On Sat, Nov 10, 2018 at 12:50:36AM -0800, john.hubbard@xxxxxxxxx wrote:
From: John Hubbard <jhubbard@xxxxxxxxxx>
An upcoming patch wants to be able to operate on each page that
get_user_pages has retrieved. In order to do that, it's best to
have a common exit point from the routine. Most of this has been
taken care of by commit df06b37ffe5a4 ("mm/gup: cache dev_pagemap while
pinning pages"), but there was one case remaining.
Also, there was still an unnecessary shadow declaration (with a
different type) of the "ret" variable, which this commit removes.
Cc: Keith Busch <keith.busch@xxxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
---
mm/gup.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index f76e77a2d34b..55a41dee0340 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -696,12 +696,11 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (!vma || start >= vma->vm_end) {
vma = find_extend_vma(mm, start);
if (!vma && in_gate_area(mm, start)) {
- int ret;
ret = get_gate_page(mm, start & PAGE_MASK,
gup_flags, &vma,
pages ? &pages[i] : NULL);
if (ret)
- return i ? : ret;
+ goto out;
ctx.page_mask = 0;
goto next_page;
}
This also fixes a potentially leaked dev_pagemap reference count if a
failure occurs when an iteration crosses a vma boundary. I don't think
it's normal to have different vma's on a users mapped zone device memory,
but good to fix anyway.
Does not sound abnormal to me, we should promote this as a fix for the
current cycle with an updated changelog.
Andrew, should I send this patch separately, or do you have what you
need already?
thanks,
--
John Hubbard
NVIDIA
