On Mon, Oct 14, 2019 at 11:46:39AM -0700, John Hubbard wrote:
> In several routines, the "flags" argument is incorrectly
> named "write". Change it to "flags".
>
> Also, in one place, the misnaming led to an actual bug:
> "flags & FOLL_WRITE" is required, rather than just "flags".
> (That problem was flagged by krobot, in v1 of this patch.)
>
> Also, change the flags argument from int, to unsigned int.
>
> You can see that this was a simple oversight, because the
> calling code passes "flags" to the fifth argument:
>
> gup_pgd_range():
> ...
> if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr,
> PGDIR_SHIFT, next, flags, pages, nr))
>
> ...which, until this patch, the callees referred to as "write".
>
> Also, change two lines to avoid checkpatch line length
> complaints, and another line to fix another oversight
> that checkpatch called out: missing "int" on pdshift.
>
> Fixes: b798bec4741b ("mm/gup: change write parameter to flags in fast walk")
> Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> Suggested-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
> Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Cc: Christoph Hellwig <hch@xxxxxx>
> Cc: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx>
> Signed-off-by: John Hubbard <jhubbard@xxxxxxxxxx>
> ---
> mm/gup.c | 14 ++++++++------
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/mm/gup.c b/mm/gup.c
> index 23a9f9c9d377..8f236a335ae9 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -1973,7 +1973,8 @@ static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end,
> }
>
> static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
> - unsigned long end, int write, struct page **pages, int *nr)
> + unsigned long end, unsigned int flags,
> + struct page **pages, int *nr)
> {
> unsigned long pte_end;
> struct page *head, *page;
> @@ -1986,7 +1987,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
>
> pte = READ_ONCE(*ptep);
>
> - if (!pte_access_permitted(pte, write))
> + if (!pte_access_permitted(pte, flags & FOLL_WRITE))
> return 0;
>
> /* hugepages are never "special" */
> @@ -2023,7 +2024,7 @@ static int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr,
> }
>
> static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
> - unsigned int pdshift, unsigned long end, int write,
> + unsigned int pdshift, unsigned long end, unsigned int flags,
> struct page **pages, int *nr)
> {
> pte_t *ptep;
> @@ -2033,7 +2034,7 @@ static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
> ptep = hugepte_offset(hugepd, addr, pdshift);
> do {
> next = hugepte_addr_end(addr, end, sz);
> - if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr))
> + if (!gup_hugepte(ptep, sz, addr, end, flags, pages, nr))
> return 0;
> } while (ptep++, addr = next, addr != end);
>
> @@ -2041,7 +2042,7 @@ static int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
> }
> #else
> static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
> - unsigned pdshift, unsigned long end, int write,
> + unsigned int pdshift, unsigned long end, unsigned int flags,
> struct page **pages, int *nr)
> {
> return 0;
> @@ -2049,7 +2050,8 @@ static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr,
> #endif /* CONFIG_ARCH_HAS_HUGEPD */
>
> static int gup_huge_pmd(pmd_t orig, pmd_t *pmdp, unsigned long addr,
> - unsigned long end, unsigned int flags, struct page **pages, int *nr)
> + unsigned long end, unsigned int flags,
> + struct page **pages, int *nr)
> {
> struct page *head, *page;
> int refs;
> --
> 2.23.0
>
>
