On Thu, Nov 09, 2017 at 06:10:39AM -0500, Devesh Sharma wrote: > Putting a read barrier before issuing a read on valid bit > is incorrect. When checking for the validity of CQE in the > CQ buffer the code must wait for the read-barrier to finish > after issuing a read operation on CQE valid bit. > > Signed-off-by: Devesh Sharma <devesh.sharma@xxxxxxxxxxxx> > providers/bnxt_re/main.h | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) This is probably fine > + uint8_t valid = 0; > + > + valid = ((le32toh(hdr->flg_st_typ_ph) & > + BNXT_RE_BCQE_PH_MASK) == cq->phase); Hrm, Techincally this should be something like le32toh(atomic_read(hdr->flg_st_typ_ph)) And the the kernel version of this should be using READ_ONCE() In user space we should probably create a udma_from_device_read_once(x) That incorporates the barrier and the 'access_once' semantics.. Jason -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
