Re: [PATCH V2 rdma-next 4/4] RDMA/hns: Fix the illegal memory operation when cross page

["Wei Hu (Xavier)" <xavier.huwei@huawei.com>]

On 2018/5/25 5:40, Jason Gunthorpe wrote:
> On Wed, May 23, 2018 at 06:16:30PM +0800, Wei Hu (Xavier) wrote:
>> This patch fixed the potential illegal operation when using the
>> extend sge buffer cross page in post send operation. The bug
>> will cause the calltrace.
> Should include the oops for reference here..
OK, we will fix it in v3.
Thanks
>> Reported-by: Jie Chen <chenjie103@huawei.com>
>> Reported-by: Xiping Zhang (Francis) <zhangxiping3@huawei.com>
>> Fixes: b1c158350968("RDMA/hns: Get rid of virt_to_page and vmap calls after dma_alloc_coherent")
>> Signed-off-by: Wei Hu (Xavier) <xavier.huwei@huawei.com>
>>
>> v1->v2: Modify the Fixes statement according to Leon's comment.
>>  drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 70 +++++++++++++++++++++---------
>>  drivers/infiniband/hw/hns/hns_roce_hw_v2.h |  1 +
>>  2 files changed, 51 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> index a70d07b..62c1eb5 100644
>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> @@ -52,6 +52,52 @@ static void set_data_seg_v2(struct hns_roce_v2_wqe_data_seg *dseg,
>>  	dseg->len  = cpu_to_le32(sg->length);
>>  }
>>  
>> +static void set_extend_sge(struct hns_roce_qp *qp, struct ib_send_wr *wr,
>> +			   unsigned int *sge_ind)
>> +{
>> +	struct hns_roce_v2_wqe_data_seg *dseg;
>> +	struct ib_sge *sg;
>> +	int num_in_wqe = 0;
>> +	int extend_sge_num;
>> +	int fi_sge_num;
>> +	int se_sge_num;
>> +	int shift;
>> +	int i;
>> +
>> +	if (qp->ibqp.qp_type == IB_QPT_RC || qp->ibqp.qp_type == IB_QPT_UC)
>> +		num_in_wqe = HNS_ROCE_V2_UC_RC_SGE_NUM_IN_WQE;
>> +	extend_sge_num = wr->num_sge - num_in_wqe;
>> +	sg = wr->sg_list + num_in_wqe;
>> +	shift = qp->hr_buf.page_shift;
>> +
>> +	/*
>> +	 * Check whether wr->num_sge sges are in the same page. If not, we
>> +	 * should calculate how many sges in the first page and the second
>> +	 * page.
>> +	 */
>> +	dseg = get_send_extend_sge(qp, (*sge_ind) & (qp->sge.sge_cnt - 1));
>> +	fi_sge_num = (((((u64)dseg >> shift) + 1) << shift) - (u64)dseg) /
>> +		      sizeof(struct hns_roce_v2_wqe_data_seg);
> desg is a pointer.. that u64 should be a uinptr_t
>
> And it is better written as
>
>   (round_up((uintptr_t)dseg, 1 << shift) - (uintptr)desg)/sizeof(struct hns_roce_v2_wqe_data_seg)
>
> if I got it right..
Ok, we will fix it v3.
Thanks

Wei Hu
> Jason
>
> .
>