Re: [PATCH v6 03/25] rtrs: private headers with rtrs protocol structs and helpers

Jinpu Wang
2020-01-03T13:48:32Z

On Tue, Dec 31, 2019 at 1:07 AM Bart Van Assche <bvanassche@acm.org> wrote:
>
> On 2019-12-30 02:29, Jack Wang wrote:
> > +static inline u32 rtrs_to_io_rsp_imm(u32 msg_id, int errno, bool w_inval)
> > +{
> > + enum rtrs_imm_type type;
> > + u32 payload;
> > +
> > + /* 9 bits for errno, 19 bits for msg_id */
> > + payload = (abs(errno) & 0x1ff) << 19 | (msg_id & 0x7ffff);
> > + type = (w_inval ? RTRS_IO_RSP_W_INV_IMM : RTRS_IO_RSP_IMM);
> > +
> > + return rtrs_to_imm(type, payload);
> > +}
> > +
> > +static inline void rtrs_from_io_rsp_imm(u32 payload, u32 *msg_id, int *errno)
> > +{
> > + /* 9 bits for errno, 19 bits for msg_id */
> > + *msg_id = (payload & 0x7ffff);
> > + *errno = -(int)((payload >> 19) & 0x1ff);
> > +}
>
> The above comments mention that 19 bits are used for msg_id. The 0x7ffff
> mask however has 23 bits set. Did I see that correctly? If so, does that
> mean that the errno and msg_id bitfields overlap partially?
Double checked with calculator 0x7ffff is 19 bits set, not 23 bits :)
>
> Thanks,
>
> Bart.