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

Gustavo A. R. Silva
2022-11-19T07:49:37Z

On Sat, Nov 19, 2022 at 01:20:09AM -0600, Gustavo A. R. Silva wrote:
> 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. :)

except that... it seems sp->u.iocb_cmd.u.ctarg.rsp is a pointer to void
and not a struct of type struct ct_sns_gpnft_rsp. :O

drivers/scsi/qla2xxx/qla_def.h:474:
struct ct_arg {
void *iocb;
u16 nport_handle;
dma_addr_t req_dma;
dma_addr_t rsp_dma;
u32 req_size;
u32 rsp_size;
u32 req_allocated_size;
u32 rsp_allocated_size;
void *req;
void *rsp;
port_id_t id;
};

I wonder if you wanted to point out something entirely different...?

--
Gustavo