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    SubjectRe: [PATCH v2 03/15] NTB: Fix UB/bug in ntb_mw_get_align()
    On Sun, Dec 3, 2017 at 2:17 PM, Serge Semin <fancer.lancer@gmail.com> wrote:
    > Simple (1 << pidx) operation causes undefined behaviour when
    > pidx >= 32. It must be casted to u64 to match the actual return
    > value of ntb_link_is_up() method, so to have all the possible
    > peer indexes covered and to get rid of undefined behaviour.
    > Additionally there are special macros in "linux/bitops.h" to perform
    > the bit-set-shift operations, so it's recommended to have them used
    > for proper bit setting.

    This looks good to me, but also seems like a bug fix. Please comment
    on if this is not noticed.

    Thanks,
    Jon

    >
    > Signed-off-by: Serge Semin <fancer.lancer@gmail.com>
    > Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
    > ---
    > include/linux/ntb.h | 2 +-
    > 1 file changed, 1 insertion(+), 1 deletion(-)
    >
    > diff --git a/include/linux/ntb.h b/include/linux/ntb.h
    > index c1646f2c6344..488e586fb76c 100644
    > --- a/include/linux/ntb.h
    > +++ b/include/linux/ntb.h
    > @@ -764,7 +764,7 @@ static inline int ntb_mw_get_align(struct ntb_dev *ntb, int pidx, int widx,
    > resource_size_t *size_align,
    > resource_size_t *size_max)
    > {
    > - if (!(ntb_link_is_up(ntb, NULL, NULL) & (1 << pidx)))
    > + if (!(ntb_link_is_up(ntb, NULL, NULL) & BIT_ULL(pidx)))
    > return -ENOTCONN;
    >
    > return ntb->ops->mw_get_align(ntb, pidx, widx, addr_align, size_align,
    > --
    > 2.12.0
    >

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