Re: [PATCH for-next 2/2] RDMA/hns: Fix alignment problem of the doorbell

Liuyixian (Eason)
2017-12-28T06:51:04Z

On 2017/12/28 1:40, Ruhl, Michael J wrote:
>> -----Original Message-----
>> From: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org [mailto:linux-rdma-
>> owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org] On Behalf Of Yixian Liu
>> Sent: Monday, December 25, 2017 8:37 AM
>> To: jgg-uk2M96/98Pc@public.gmane.org; leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org
>> Cc: dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org; linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> Subject: [PATCH for-next 2/2] RDMA/hns: Fix alignment problem of the
>> doorbell
>>
>> The array defined for doorbell is not guaranteed to be 64 bit
>> aligned while we write it to the hardware with 64 bit
>> alignment required.
>>
>> This patch fixes this problem by defining a union for doorbell
>> to make sure it 64 bit alignment.
>>
>> Signed-off-by: Yixian Liu <liuyixian-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Lijun Ou <oulijun-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
>> Signed-off-by: Wei Hu (Xavier) <xavier.huwei-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
>> ---
>> drivers/infiniband/hw/hns/hns_roce_device.h | 5 +++++
>> drivers/infiniband/hw/hns/hns_roce_hw_v2.c | 16 ++++++++--------
>> 2 files changed, 13 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h
>> b/drivers/infiniband/hw/hns/hns_roce_device.h
>> index dde5178..defc4ee 100644
>> --- a/drivers/infiniband/hw/hns/hns_roce_device.h
>> +++ b/drivers/infiniband/hw/hns/hns_roce_device.h
>> @@ -569,6 +569,11 @@ struct hns_roce_eq_table {
>> void __iomem **eqc_base; /* only for hw v1 */
>> };
>>
>> +union hns_roce_db {
>> + u64 doorbell64;
>
> Are there any concerns with big endian/little ending for this value?
>
> Mike
>

I will consider this issue in patch v3, Mike, thank you!

>> + u32 doorbell[2];
>> +};
>> +
>> struct hns_roce_caps {
>> u8 num_ports;
>> int gid_table_len[HNS_ROCE_MAX_PORTS];
>> diff --git a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> index 7f393f6..ee26bbd 100644
>> --- a/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> +++ b/drivers/infiniband/hw/hns/hns_roce_hw_v2.c
>> @@ -3172,33 +3172,33 @@ static int hns_roce_v2_modify_cq(struct ib_cq
>> *cq, u16 cq_count, u16 cq_period)
>>
>> static void set_eq_cons_index_v2(struct hns_roce_eq *eq)
>> {
>> - u32 doorbell[2];
>> + union hns_roce_db db;
>>
>> - doorbell[0] = 0;
>> - doorbell[1] = 0;
>> + db.doorbell[0] = 0;
>> + db.doorbell[1] = 0;
>>
>> if (eq->type_flag == HNS_ROCE_AEQ) {
>> - roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
>> + roce_set_field(db.doorbell[0],
>> HNS_ROCE_V2_EQ_DB_CMD_M,
>> HNS_ROCE_V2_EQ_DB_CMD_S,
>> eq->arm_st ==
>> HNS_ROCE_V2_EQ_ALWAYS_ARMED ?
>> HNS_ROCE_EQ_DB_CMD_AEQ :
>> HNS_ROCE_EQ_DB_CMD_AEQ_ARMED);
>> } else {
>> - roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_TAG_M,
>> + roce_set_field(db.doorbell[0],
>> HNS_ROCE_V2_EQ_DB_TAG_M,
>> HNS_ROCE_V2_EQ_DB_TAG_S, eq->eqn);
>>
>> - roce_set_field(doorbell[0], HNS_ROCE_V2_EQ_DB_CMD_M,
>> + roce_set_field(db.doorbell[0],
>> HNS_ROCE_V2_EQ_DB_CMD_M,
>> HNS_ROCE_V2_EQ_DB_CMD_S,
>> eq->arm_st ==
>> HNS_ROCE_V2_EQ_ALWAYS_ARMED ?
>> HNS_ROCE_EQ_DB_CMD_CEQ :
>> HNS_ROCE_EQ_DB_CMD_CEQ_ARMED);
>> }
>>
>> - roce_set_field(doorbell[1], HNS_ROCE_V2_EQ_DB_PARA_M,
>> + roce_set_field(db.doorbell[1], HNS_ROCE_V2_EQ_DB_PARA_M,
>> HNS_ROCE_V2_EQ_DB_PARA_S,
>> (eq->cons_index & HNS_ROCE_V2_CONS_IDX_M));
>>
>> - hns_roce_write64_k(doorbell, eq->doorbell);
>> + hns_roce_write64_k(db.doorbell, eq->doorbell);
>>
>> /* Make sure we update the consumer index of EQ before
>> * accessing it later
>> --
>> 1.9.1
>>
>> --
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>
> .