Re: [PATCH v1.2 17/16] arcmsr: fixed calling scsi_scan_host after all initialization done

[Tomas Henzl <thenzl@redhat.com>]

On 05/16/2014 01:46 PM, ching wrote:
> Hi Tomas,
>
> Although in http://www.makelinux.net/ldd3/chp-7-sect-6, there said to flush the shared workqueue requires calling function
> flush_scheduled_work.
>
> But in kernel workqueue.c, there are comment of flush_scheduled_work said that 
> "In most situations flushing the entire workqueue is overkill; you merely need to know that a particular work item isn't
> queued and isn't running."
>
> In such cases use flush_work is OK.
> This can be proved in so many kernel device driver calling flush_work instead of flush_scheduled_work.

Yes, I think now this is correct, I have no more objections.

Thanks, Tomas,

>
>
> On Thu, 2014-05-15 at 13:52 +0200, Tomas Henzl wrote:
>> On 05/15/2014 12:49 PM, ching wrote:
>>> Hi Tomas,
>>>
>>> Then I will have a patch 18/16 to replace flush_scheduled_work with flush_work.
>>> Thanks for your advice.
>> Here http://www.makelinux.net/ldd3/chp-7-sect-6 is a short text about workqueue,
>> the use of schedule_work in your sources means that you use the global queue.
>> If that is true, flush_scheduled_work is the right choice.
>>
>>> On Wed, 2014-05-14 at 14:53 +0200, Tomas Henzl wrote:
>>>> On 05/14/2014 01:55 PM, ching wrote:
>>>>> From: Ching<ching2048@areca.com.tw>
>>>>>
>>>>> This is a new patch after patch v1.1 series.
>>>>>
>>>>> Fixed calling scsi_scan_host until all initialization are done.
>>>>> And fixed error path free allocated resource.
>>>>>
>>>>> Signed-off-by: Ching<ching2048@areca.com.tw>
>>>>> ---
>>>>>
>>>>> diff -uprN a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
>>>>> --- a/drivers/scsi/arcmsr/arcmsr_hba.c	2014-05-08 17:45:34.000000000 +0800
>>>>> +++ b/drivers/scsi/arcmsr/arcmsr_hba.c	2014-05-14 18:29:30.000000000 +0800
>>>>> @@ -112,6 +112,7 @@ static void arcmsr_hbaD_message_isr(stru
>>>>>  static void arcmsr_hardware_reset(struct AdapterControlBlock *acb);
>>>>>  static const char *arcmsr_info(struct Scsi_Host *);
>>>>>  static irqreturn_t arcmsr_interrupt(struct AdapterControlBlock *acb);
>>>>> +static void arcmsr_free_irq(struct pci_dev *, struct AdapterControlBlock *);
>>>>>  static int arcmsr_adjust_disk_queue_depth(struct scsi_device *sdev,
>>>>>  					  int queue_depth, int reason)
>>>>>  {
>>>>> @@ -778,12 +779,11 @@ static int arcmsr_probe(struct pci_dev *
>>>>>  	}
>>>>>  	error = scsi_add_host(host, &pdev->dev);
>>>>>  	if(error){
>>>>> -		goto RAID_controller_stop;
>>>>> +		goto free_ccb_pool;
>>>>>  	}
>>>>>  	if (arcmsr_request_irq(pdev, acb) == ARC_FAILURE)
>>>>>  		goto scsi_host_remove;
>>>>>  	arcmsr_iop_init(acb);
>>>>> -    	scsi_scan_host(host);
>>>>>  	INIT_WORK(&acb->arcmsr_do_message_isr_bh, arcmsr_message_isr_bh_fn);
>>>>>  	atomic_set(&acb->rq_map_token, 16);
>>>>>  	atomic_set(&acb->ante_token_value, 16);
>>>>> @@ -795,13 +795,17 @@ static int arcmsr_probe(struct pci_dev *
>>>>>  	add_timer(&acb->eternal_timer);
>>>>>  	if(arcmsr_alloc_sysfs_attr(acb))
>>>>>  		goto out_free_sysfs;
>>>>> +    	scsi_scan_host(host);
>>>>>  	return 0;
>>>>>  out_free_sysfs:
>>>>> -scsi_host_remove:
>>>>> -	scsi_remove_host(host);
>>>>> -RAID_controller_stop:
>>>>> +	del_timer_sync(&acb->eternal_timer);
>>>>> + 	flush_work(&acb->arcmsr_do_message_isr_bh);
>>>> In your driver you use both flush_work(struct work_struct *) and flush_scheduled_work(),
>>>> the second form is used used to flush the shared workqueue. 
>>>> That said (and I think you use just one queue) you should decide which one is correct.
>>>> In my previous mail I have asked about flush_work because i have it seen elsewhere in
>>>> your code, now I've noticed the use of schedule_work and that means that you are using the global wq.
>>>>  
>>>>
>>>>>  	arcmsr_stop_adapter_bgrb(acb);
>>>>>  	arcmsr_flush_adapter_cache(acb);
>>>>> +	arcmsr_free_irq(pdev, acb);
>>>>> +scsi_host_remove:
>>>>> +	scsi_remove_host(host);
>>>>> +free_ccb_pool:
>>>>>  	arcmsr_free_ccb_pool(acb);
>>>>>  free_hbb_mu:
>>>>>  	arcmsr_free_mu(acb);
>>>>>
>>>>>
>>>>> --
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