From 08be37b798921af207e78082fe261a6ca8be5024 Mon Sep 17 00:00:00 2001 From: John Hubbard Date: Fri, 30 Nov 2018 14:08:53 -0800 Subject: mm/gup: finish consolidating error handling Commit df06b37ffe5a ("mm/gup: cache dev_pagemap while pinning pages") attempted to operate on each page that get_user_pages had retrieved. In order to do that, it created a common exit point from the routine. However, one case was missed, which this patch fixes up. Also, there was still an unnecessary shadow declaration (with a different type) of the "ret" variable, which this patch removes. Keith's description of the situation is: 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. I actually thought that this code: /* first iteration or cross vma bound */ if (!vma || start >= vma->vm_end) { vma = find_extend_vma(mm, start); if (!vma && in_gate_area(mm, start)) { ret = get_gate_page(mm, start & PAGE_MASK, gup_flags, &vma, pages ? &pages[i] : NULL); if (ret) goto out; dealt with the "you're trying to pin the gate page, as part of this call", rather than the generic case of crossing a vma boundary. (I think there's a fine point that I must be overlooking.) But it's still a valid case, either way. Link: http://lkml.kernel.org/r/20181121081402.29641-2-jhubbard@nvidia.com Fixes: df06b37ffe5a4 ("mm/gup: cache dev_pagemap while pinning pages") Signed-off-by: John Hubbard Reviewed-by: Keith Busch Cc: Dan Williams Cc: Kirill A. Shutemov Cc: Dave Hansen Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/gup.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'mm/gup.c') diff --git a/mm/gup.c b/mm/gup.c index aa43620a3270..8cb68a50dbdf 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -702,12 +702,11 @@ 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; } -- cgit v1.2.3-55-g7522