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scsi: hisi_sas: Don't bother clearing status buffer IU in task prep 

For struct hisi_sas_status_buffer, it contains struct hisi_sas_err_record
and iu[1024]. The struct iu[1024] will be filled fully by the response of
disks, so it is not need to initialize them to 0, but for the struct
hisi_sas_err_record, SAS controller only fill some fields of
hisi_sas_err_record according to hw designer, so it should be initialised
to 0.  After the change, cpu utilization percentage of memset() is changed
from 1.7% to 0.12%.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: John Garry <john.garry@huawei.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Xiang Chen 2019-08-05 21:48:04 +08:00 committed by Martin K. Petersen
parent 445ee2de11
commit d380f55503
1 changed files with 4 additions and 2 deletions
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6
drivers/scsi/hisi_sas/hisi_sas_main.c
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@ -545,7 +545,8 @@ static int hisi_sas_task_prep(struct sas_task *task,
memset(slot->cmd_hdr, 0, sizeof(struct hisi_sas_cmd_hdr));
memset(hisi_sas_cmd_hdr_addr_mem(slot), 0, HISI_SAS_COMMAND_TABLE_SZ);
memset(hisi_sas_status_buf_addr_mem(slot), 0, HISI_SAS_STATUS_BUF_SZ);
memset(hisi_sas_status_buf_addr_mem(slot), 0,
sizeof(struct hisi_sas_err_record));
switch (task->task_proto) {
case SAS_PROTOCOL_SMP:
@ -2005,7 +2006,8 @@ hisi_sas_internal_abort_task_exec(struct hisi_hba *hisi_hba, int device_id,
memset(slot->cmd_hdr, 0, sizeof(struct hisi_sas_cmd_hdr));
memset(hisi_sas_cmd_hdr_addr_mem(slot), 0, HISI_SAS_COMMAND_TABLE_SZ);
memset(hisi_sas_status_buf_addr_mem(slot), 0, HISI_SAS_STATUS_BUF_SZ);
memset(hisi_sas_status_buf_addr_mem(slot), 0,
sizeof(struct hisi_sas_err_record));
hisi_sas_task_prep_abort(hisi_hba, slot, device_id,
abort_flag, task_tag);