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SubjectRe: [PATCH v5 03/23] scsi: hisi_sas: optimise the usage of hisi_hba.lock
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On 10/06/2017 21:44, kbuild test robot wrote:
> Hi Xiang,
>
> [auto build test WARNING on mkp-scsi/for-next]
> [also build test WARNING on v4.12-rc4 next-20170609]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/John-Garry/hisi_sas-hip08-support/20170611-014437
> base: https://git.kernel.org/pub/scm/linux/kernel/git/mkp/scsi.git for-next
>
>
> coccinelle warnings: (new ones prefixed by >>)
>
>>> drivers/scsi/hisi_sas/hisi_sas_main.c:1208:1-18: ERROR: nested lock+irqsave that reuses flags from line 1178.
>
> vim +1208 drivers/scsi/hisi_sas/hisi_sas_main.c
>
> bf95e9ccc Xiang Chen 2017-06-09 1172 if (rc) {
> bf95e9ccc Xiang Chen 2017-06-09 1173 spin_unlock_irqrestore(&hisi_hba->lock, flags);
> 441c27401 John Garry 2016-08-24 1174 goto err_out;
> bf95e9ccc Xiang Chen 2017-06-09 1175 }
> bf95e9ccc Xiang Chen 2017-06-09 1176 spin_unlock_irqrestore(&hisi_hba->lock, flags);
> bf95e9ccc Xiang Chen 2017-06-09 1177
> bf95e9ccc Xiang Chen 2017-06-09 @1178 spin_lock_irqsave(&dq->lock, flags);
> bf95e9ccc Xiang Chen 2017-06-09 1179 rc = hisi_hba->hw->get_free_slot(hisi_hba, dq);
> 441c27401 John Garry 2016-08-24 1180 if (rc)
> 441c27401 John Garry 2016-08-24 1181 goto err_out_tag;
> 441c27401 John Garry 2016-08-24 1182
> bf95e9ccc Xiang Chen 2017-06-09 1183 dlvry_queue = dq->id;
> bf95e9ccc Xiang Chen 2017-06-09 1184 dlvry_queue_slot = dq->wr_point;
> bf95e9ccc Xiang Chen 2017-06-09 1185
> 441c27401 John Garry 2016-08-24 1186 slot = &hisi_hba->slot_info[slot_idx];
> 441c27401 John Garry 2016-08-24 1187 memset(slot, 0, sizeof(struct hisi_sas_slot));
> 441c27401 John Garry 2016-08-24 1188
> 441c27401 John Garry 2016-08-24 1189 slot->idx = slot_idx;
> 441c27401 John Garry 2016-08-24 1190 slot->n_elem = n_elem;
> 441c27401 John Garry 2016-08-24 1191 slot->dlvry_queue = dlvry_queue;
> 441c27401 John Garry 2016-08-24 1192 slot->dlvry_queue_slot = dlvry_queue_slot;
> 441c27401 John Garry 2016-08-24 1193 cmd_hdr_base = hisi_hba->cmd_hdr[dlvry_queue];
> 441c27401 John Garry 2016-08-24 1194 slot->cmd_hdr = &cmd_hdr_base[dlvry_queue_slot];
> 441c27401 John Garry 2016-08-24 1195 slot->task = task;
> 441c27401 John Garry 2016-08-24 1196 slot->port = port;
> 441c27401 John Garry 2016-08-24 1197 task->lldd_task = slot;
> 441c27401 John Garry 2016-08-24 1198
> 441c27401 John Garry 2016-08-24 1199 memset(slot->cmd_hdr, 0, sizeof(struct hisi_sas_cmd_hdr));
> 441c27401 John Garry 2016-08-24 1200
> 441c27401 John Garry 2016-08-24 1201 rc = hisi_sas_task_prep_abort(hisi_hba, slot, device_id,
> 441c27401 John Garry 2016-08-24 1202 abort_flag, task_tag);
> 441c27401 John Garry 2016-08-24 1203 if (rc)
> 441c27401 John Garry 2016-08-24 1204 goto err_out_tag;
> 441c27401 John Garry 2016-08-24 1205
> 405314df5 John Garry 2017-03-23 1206
> 405314df5 John Garry 2017-03-23 1207 list_add_tail(&slot->entry, &sas_dev->list);
> 54c9dd2d2 John Garry 2017-03-23 @1208 spin_lock_irqsave(&task->task_state_lock, flags);

I don't think that reusing flags variable is in error, as there would be
no nested spinlock at this point within the function.

If it is not recommended or not permitted to reuse flags variable for
separate spinlocks, then that can be changed - I don't know.

John

> 441c27401 John Garry 2016-08-24 1209 task->task_state_flags |= SAS_TASK_AT_INITIATOR;
> 54c9dd2d2 John Garry 2017-03-23 1210 spin_unlock_irqrestore(&task->task_state_lock, flags);
> 441c27401 John Garry 2016-08-24 1211
>
> :::::: The code at line 1208 was first introduced by commit
> :::::: 54c9dd2d26d0951891516a956893428feb9aea17 scsi: hisi_sas: fix some sas_task.task_state_lock locking
>
> :::::: TO: John Garry <john.garry@huawei.com>
> :::::: CC: Martin K. Petersen <martin.petersen@oracle.com>
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
>
> .
>


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