Re: [PATCH v3 1/3] net: mana: Add flex array to struct mana_cfg_rx_steer_req_v2

[Justin Stitt]

On Mon, Apr 8, 2024 at 2:35 PM Justin Stitt <justinstitt@xxxxxxxxxx> wrote:
>
> Hi,
>
> On Sat, Apr 06, 2024 at 04:23:35PM +0200, Erick Archer wrote:
> > The "struct mana_cfg_rx_steer_req_v2" uses a dynamically sized set of
> > trailing elements. Specifically, it uses a "mana_handle_t" array. So,
> > use the preferred way in the kernel declaring a flexible array [1].
> >
> > At the same time, prepare for the coming implementation by GCC and Clang
> > of the __counted_by attribute. Flexible array members annotated with
> > __counted_by can have their accesses bounds-checked at run-time via
> > CONFIG_UBSAN_BOUNDS (for array indexing) and CONFIG_FORTIFY_SOURCE (for
> > strcpy/memcpy-family functions).
> >
> > This is a previous step to refactor the two consumers of this structure.
> >
> >  drivers/infiniband/hw/mana/qp.c
> >  drivers/net/ethernet/microsoft/mana/mana_en.c
> >
> > The ultimate goal is to avoid the open-coded arithmetic in the memory
> > allocator functions [2] using the "struct_size" macro.
> >
> > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#zero-length-and-one-element-arrays [1]
> > Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [2]
> > Signed-off-by: Erick Archer <erick.archer@xxxxxxxxxxx>
>
> I think this could have all been one patch, I found myself jumping
> around the three patches here piecing together context.

I now see Leon said to combine them in v2. Whoops, sorry to give
conflicting feedback.

>
> Reviewed-by: Justin Stitt <justinstitt@xxxxxxxxxx>
>
> > ---
> >  include/net/mana/mana.h | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
> > index 4eeedf14711b..561f6719fb4e 100644
> > --- a/include/net/mana/mana.h
> > +++ b/include/net/mana/mana.h
> > @@ -670,6 +670,7 @@ struct mana_cfg_rx_steer_req_v2 {
> >       u8 hashkey[MANA_HASH_KEY_SIZE];
> >       u8 cqe_coalescing_enable;
> >       u8 reserved2[7];
> > +     mana_handle_t indir_tab[] __counted_by(num_indir_entries);
> >  }; /* HW DATA */
> >
> >  struct mana_cfg_rx_steer_resp {
> > --
> > 2.25.1
> >
>
> Thanks
> Justin