Re: [PATCH 2/2][next] scsi: qla2xxx: Use struct_size() in code related to struct ct_sns_gpnft_rsp

Gustavo A. R. Silva
2022-11-19T07:20:30Z

On Fri, Nov 18, 2022 at 11:10:44PM -0800, Kees Cook wrote:
> On Fri, Nov 18, 2022 at 05:47:56PM -0600, Gustavo A. R. Silva wrote:
> > Prefer struct_size() over open-coded versions of idiom:
> >
> > sizeof(struct-with-flex-array) + sizeof(typeof-flex-array-elements) * count
> >
> > where count is the max number of items the flexible array is supposed to
> > contain.
> >
> > Link: https://github.com/KSPP/linux/issues/160
> > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
> > ---
> > drivers/scsi/qla2xxx/qla_gs.c | 5 ++---
> > 1 file changed, 2 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/scsi/qla2xxx/qla_gs.c b/drivers/scsi/qla2xxx/qla_gs.c
> > index 69d3bc795f90..27e1df56b0fb 100644
> > --- a/drivers/scsi/qla2xxx/qla_gs.c
> > +++ b/drivers/scsi/qla2xxx/qla_gs.c
> > @@ -4072,9 +4072,8 @@ int qla24xx_async_gpnft(scsi_qla_host_t *vha, u8 fc4_type, srb_t *sp)
> > }
> > sp->u.iocb_cmd.u.ctarg.req_size = GPN_FT_REQ_SIZE;
> >
> > - rspsz = sizeof(struct ct_sns_gpnft_rsp) +
> > - (vha->hw->max_fibre_devices *
> > - sizeof(struct ct_sns_gpn_ft_data));
> > + rspsz = struct_size((struct ct_sns_gpnft_rsp *)0, entries,
> > + vha->hw->max_fibre_devices);
>
> This should be able to use sp->u.iocb_cmd.u.ctarg.rsp instead of the
> explicit struct with a NULL. (It's just using typeof() internally, so
> it's okay that it isn't allocated yet.)

mmh... yeah; and considering they're already going all the way down to
sp->u.iocb_cmd.u.ctarg.req_size, I think accessing sp->u.iocb_cmd.u.ctarg.rsp
is perfectly fine. :)

I'll respin. Thanks for the feedback!
--
Gustavo

>
> -Kees
>
> >
> > sp->u.iocb_cmd.u.ctarg.rsp = dma_alloc_coherent(&vha->hw->pdev->dev,
> > rspsz,
> > --
> > 2.34.1
> >
>
> --
> Kees Cook