On 2019/11/23 2:09, Jason Gunthorpe wrote: > On Fri, Nov 22, 2019 at 02:58:44AM +0000, Zengtao (B) wrote: >>> From: linux-rdma-owner@xxxxxxxxxxxxxxx >>> [mailto:linux-rdma-owner@xxxxxxxxxxxxxxx] On Behalf Of Weihang Li >>> Sent: Thursday, November 21, 2019 9:19 AM >>> To: jgg@xxxxxxxx; leon@xxxxxxxxxx >>> Cc: dledford@xxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx; Linuxarm >>> Subject: [PATCH rdma-core 1/7] libhns: Fix calculation errors with ilog32() >>> >>> Current calculation results using ilog32() is larger than expected, which >>> will lead to driver broken. The following is the log when QP creations >>> fails: >>> >>> [ 81.294844] hns3 0000:7d:00.0 hns_0: check SQ size error! >>> [ 81.294848] hns3 0000:7d:00.0 hns_0: check SQ size error! >>> [ 81.300225] hns3 0000:7d:00.0 hns_0: Sanity check sq size failed >>> [ 81.300227] hns3 0000:7d:00.0: hns_roce_set_user_sq_size error for >>> create qp >>> [ 81.305602] hns3 0000:7d:00.0 hns_0: Sanity check sq size failed >>> [ 81.305603] hns3 0000:7d:00.0: hns_roce_set_user_sq_size error for >>> create qp >>> [ 81.311589] hns3 0000:7d:00.0 hns_0: Create RC QP 0x000000 >>> failed(-22) >>> [ 81.318603] hns3 0000:7d:00.0 hns_0: Create RC QP 0x000000 >>> failed(-22) >>> >>> Fixes: b6cd213b276f ("libhns: Refactor for creating qp") >>> Signed-off-by: Weihang Li <liweihang@xxxxxxxxxxxxx> >>> providers/hns/hns_roce_u_verbs.c | 11 ++++++----- >>> 1 file changed, 6 insertions(+), 5 deletions(-) >>> >>> diff --git a/providers/hns/hns_roce_u_verbs.c >>> b/providers/hns/hns_roce_u_verbs.c >>> index 9d222c0..bd5060d 100644 >>> +++ b/providers/hns/hns_roce_u_verbs.c >>> @@ -645,7 +645,8 @@ static int hns_roce_calc_qp_buff_size(struct >>> ibv_pd *pd, struct ibv_qp_cap *cap, >>> int page_size = to_hr_dev(pd->context->device)->page_size; >>> >>> if (to_hr_dev(pd->context->device)->hw_version == >>> HNS_ROCE_HW_VER1) { >>> - qp->rq.wqe_shift = ilog32(sizeof(struct hns_roce_rc_rq_wqe)); >>> + qp->rq.wqe_shift = >>> + ilog32(sizeof(struct hns_roce_rc_rq_wqe)) - 1; >>> >>> qp->buf_size = align((qp->sq.wqe_cnt << qp->sq.wqe_shift), >>> page_size) + >>> @@ -662,7 +663,7 @@ static int hns_roce_calc_qp_buff_size(struct >>> ibv_pd *pd, struct ibv_qp_cap *cap, >>> } else { >>> unsigned int rqwqe_size = HNS_ROCE_SGE_SIZE * >>> cap->max_recv_sge; >>> >>> - qp->rq.wqe_shift = ilog32(rqwqe_size); >>> + qp->rq.wqe_shift = ilog32(rqwqe_size) - 1; >>> >>> if (qp->sq.max_gs > HNS_ROCE_SGE_IN_WQE || type == >>> IBV_QPT_UD) >>> qp->sge.sge_shift = HNS_ROCE_SGE_SHIFT; >>> @@ -747,8 +748,8 @@ static void hns_roce_set_qp_params(struct >>> ibv_pd *pd, >>> qp->rq.wqe_cnt = >>> roundup_pow_of_two(attr->cap.max_recv_wr); >>> } >>> >>> - qp->sq.wqe_shift = ilog32(sizeof(struct hns_roce_rc_send_wqe)); >>> - qp->sq.shift = ilog32(qp->sq.wqe_cnt); >>> + qp->sq.wqe_shift = ilog32(sizeof(struct hns_roce_rc_send_wqe)) - 1; >>> + qp->sq.shift = ilog32(qp->sq.wqe_cnt) - 1; >> >> One suggestion, it's better to introduce a new micro instead of ilog32(x) -1. > > Is the -1 even correct? > > I would have guessed something called shift wants to be: > > shift = ilog32(qp->sq.wqe_cnt - 1) > > Such that > 1 << shift == wqe_cnt > When wqe_cnt is a power of two. > 1 << shift > wqe_cnt > When wqe_cnt is not a power of two. > > Jason > That's right, shift = ilog32(n - 1) is always right, but result of ilog32(n) - 1 is only correct when n is a power of two. Will modify to ilog32(n - 1). Thank you Weihang > . >
