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Subject: Re: [PATCH] scsi: libsas: Grab the host lock in
 sas_ata_device_link_abort()
To:     Damien Le Moal <damien.lemoal@opensource.wdc.com>,
        John Garry <john.g.garry@oracle.com>,
        Xingui Yang <yangxingui@huawei.com>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <niklas.cassel@wdc.com>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, <prime.zeng@hisilicon.com>,
        <kangfenglong@huawei.com>
References: <20221220125349.45091-1-yangxingui@huawei.com>
 <4ec9dbed-1758-d6b4-dc1d-ac42e8c22731@oracle.com>
 <c8387766-2ca0-51f3-e332-71492b13e5c1@opensource.wdc.com>
From:   Jason Yan <yanaijie@huawei.com>
Message-ID: <7347d117-6e0b-dd18-90a8-25685f757689@huawei.com>
Date:   Wed, 21 Dec 2022 10:42:52 +0800
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On 2022/12/21 8:36, Damien Le Moal wrote:
> On 2022/12/20 23:59, John Garry wrote:
>> On 20/12/2022 12:53, Xingui Yang wrote:
>>> Grab the host lock in sas_ata_device_link_abort() before calling
>>
>> This is should be the ata port lock, right? I know that the ata comments
>> say differently.
>>
>>> ata_link_abort(), as the comment in ata_link_abort() mentions.
>>>
>>
>> Can you please add a fixes tag?
>>
>>> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
>>
>> Reviewed-by: John Garry <john.g.garry@oracle.com>
>>
>>> ---
>>>    drivers/scsi/libsas/sas_ata.c | 3 +++
>>>    1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
>>> index f7439bf9cdc6..4f2017b21e6d 100644
>>> --- a/drivers/scsi/libsas/sas_ata.c
>>> +++ b/drivers/scsi/libsas/sas_ata.c
>>> @@ -889,7 +889,9 @@ void sas_ata_device_link_abort(struct domain_device *device, bool force_reset)
>>>    {
>>>    	struct ata_port *ap = device->sata_dev.ap;
>>>    	struct ata_link *link = &ap->link;
>>> +	unsigned long flags;
>>>    
>>> +	spin_lock_irqsave(ap->lock, flags);
>>>    	device->sata_dev.fis[2] = ATA_ERR | ATA_DRDY; /* tf status */
>>>    	device->sata_dev.fis[3] = ATA_ABORTED; /* tf error */
>>>    
>>> @@ -897,6 +899,7 @@ void sas_ata_device_link_abort(struct domain_device *device, bool force_reset)
>>>    	if (force_reset)
>>>    		link->eh_info.action |= ATA_EH_RESET;
>>>    	ata_link_abort(link);
> 
> Really need to add lockdep annotations in libata to avoid/catch such bugs...
> Will work on that.

Actually in libata there are many places calling ata_link_abort() not 
holding port lock. And some places are holding the real host 
lock(ata_host->lock) while calling ata_link_abort(). So if you add the 
lockdep annotations, there may be too many warnings. If these are real 
issues, we should fix them first.

Thanks,
Jason