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Message-ID: <b67e531a-1caf-89ae-dcc2-f22e0d1f09a0@huawei.com>
Date:   Fri, 5 May 2023 10:17:37 +0800
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Subject: Re: [PATCH] ata: libata-scsi: Fix get identity data failed
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To:     John Garry <john.g.garry@oracle.com>, <jejb@linux.ibm.com>,
        <martin.petersen@oracle.com>, <damien.lemoal@opensource.wdc.com>,
        <dlemoal@kernel.org>
CC:     <linux-scsi@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linuxarm@huawei.com>, <prime.zeng@hisilicon.com>,
        <kangfenglong@huawei.com>
References: <20230504131545.3409-1-yangxingui@huawei.com>
 <4ffe09f9-df67-f238-75cf-d0d16476e618@oracle.com>
From:   yangxingui <yangxingui@huawei.com>
In-Reply-To: <4ffe09f9-df67-f238-75cf-d0d16476e618@oracle.com>
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On 2023/5/4 22:24, John Garry wrote:
> On 04/05/2023 14:15, Xingui Yang wrote:
>> The function ata_get_identity() uses the helper ata_scsi_find_dev() to 
>> get
>> the ata_device structure of a scsi device.  However, when the ata device
>> is managed by libsas, ata_scsi_find_dev() returns NULL, turning
>> ata_get_identity() into a nop and always returns -ENOMSG.
>>
>> Fix this by replacing the pointer to the scsi_device struct argument 
>> with a
>> pointer to the ata_device struct in ata_sas_scsi_ioctl() and
>> ata_get_identity(). This pointer is provided by ata_scsi_ioctl() using
>> ata_scsi_find_dev() in the case of a libata managed device and by
>> sas_ioctl() using sas_to_ata_dev() in the case of a libsas managed ata
>> device.
> 
> We made a similar change in commit 141f3d6256e5 ("ata: libata-sata: Fix 
> device queue depth control"). Is there some better way to do this to 
> make it all more scalable such that we don't need to keep replacing 
> calls to ata_scsi_find_dev()?
> 
Yes, We do have a way to return the correct value in 
ata_scsi_find_dev(), and we don't need to keep replacing calls to 
ata_scsi_find_dev(). I'll update with a new version.

Thanks,
Xingui
> This was discussed earlier, along with queue depth issue (which does not 
> seem fixed, AFAIK):
> https://lore.kernel.org/linux-scsi/13e5e5e5-7dc2-8f14-3dd2-43366343842d@huawei.com/ 
> 
> 
> Thanks,
> John
> 
> 
>>
>> Signed-off-by: Xingui Yang <yangxingui@huawei.com>
>> ---
>>   drivers/ata/libata-scsi.c           | 22 +++++++++++-----------
>>   drivers/scsi/libsas/sas_scsi_host.c |  3 ++-
>>   include/linux/libata.h              |  2 +-
>>   3 files changed, 14 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
>> index 7bb12deab70c..68f2404e61d0 100644
>> --- a/drivers/ata/libata-scsi.c
>> +++ b/drivers/ata/libata-scsi.c
>> @@ -327,8 +327,7 @@ EXPORT_SYMBOL_GPL(ata_scsi_unlock_native_capacity);
>>   /**
>>    *    ata_get_identity - Handler for HDIO_GET_IDENTITY ioctl
>> - *    @ap: target port
>> - *    @sdev: SCSI device to get identify data for
>> + *    @dev: ATA device to get identify data for
>>    *    @arg: User buffer area for identify data
>>    *
>>    *    LOCKING:
>> @@ -337,10 +336,8 @@ EXPORT_SYMBOL_GPL(ata_scsi_unlock_native_capacity);
>>    *    RETURNS:
>>    *    Zero on success, negative errno on error.
>>    */
>> -static int ata_get_identity(struct ata_port *ap, struct scsi_device 
>> *sdev,
>> -                void __user *arg)
>> +static int ata_get_identity(struct ata_device *dev, void __user *arg)
>>   {
>> -    struct ata_device *dev = ata_scsi_find_dev(ap, sdev);
>>       u16 __user *dst = arg;
>>       char buf[40];
>> @@ -573,7 +570,7 @@ static bool ata_ioc32(struct ata_port *ap)
>>    * This handles both native and compat commands, so anything added
>>    * here must have a compatible argument, or check in_compat_syscall()
>>    */
>> -int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device *scsidev,
>> +int ata_sas_scsi_ioctl(struct ata_port *ap, struct ata_device *dev,
>>                unsigned int cmd, void __user *arg)
>>   {
>>       unsigned long val;
>> @@ -608,17 +605,17 @@ int ata_sas_scsi_ioctl(struct ata_port *ap, 
>> struct scsi_device *scsidev,
>>           return rc;
>>       case HDIO_GET_IDENTITY:
>> -        return ata_get_identity(ap, scsidev, arg);
>> +        return ata_get_identity(dev, arg);
>>       case HDIO_DRIVE_CMD:
>>           if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
>>               return -EACCES;
>> -        return ata_cmd_ioctl(scsidev, arg);
>> +        return ata_cmd_ioctl(dev->sdev, arg);
>>       case HDIO_DRIVE_TASK:
>>           if (!capable(CAP_SYS_ADMIN) || !capable(CAP_SYS_RAWIO))
>>               return -EACCES;
>> -        return ata_task_ioctl(scsidev, arg);
>> +        return ata_task_ioctl(dev->sdev, arg);
>>       default:
>>           rc = -ENOTTY;
>> @@ -632,8 +629,11 @@ EXPORT_SYMBOL_GPL(ata_sas_scsi_ioctl);
>>   int ata_scsi_ioctl(struct scsi_device *scsidev, unsigned int cmd,
>>              void __user *arg)
>>   {
>> -    return ata_sas_scsi_ioctl(ata_shost_to_port(scsidev->host),
>> -                scsidev, cmd, arg);
>> +    struct ata_port *ap = ata_shost_to_port(scsidev->host);
>> +
>> +    return ata_sas_scsi_ioctl(ap,
>> +            ata_scsi_find_dev(ap, scsidev),
>> +            cmd, arg);
>>   }
>>   EXPORT_SYMBOL_GPL(ata_scsi_ioctl);
>> diff --git a/drivers/scsi/libsas/sas_scsi_host.c 
>> b/drivers/scsi/libsas/sas_scsi_host.c
>> index a36fa1c128a8..c7a44ce7b2e2 100644
>> --- a/drivers/scsi/libsas/sas_scsi_host.c
>> +++ b/drivers/scsi/libsas/sas_scsi_host.c
>> @@ -789,7 +789,8 @@ int sas_ioctl(struct scsi_device *sdev, unsigned 
>> int cmd, void __user *arg)
>>       struct domain_device *dev = sdev_to_domain_dev(sdev);
>>       if (dev_is_sata(dev))
>> -        return ata_sas_scsi_ioctl(dev->sata_dev.ap, sdev, cmd, arg);
>> +        return ata_sas_scsi_ioctl(dev->sata_dev.ap,
>> +                sas_to_ata_dev(dev), cmd, arg);
>>       return -EINVAL;
>>   }
>> diff --git a/include/linux/libata.h b/include/linux/libata.h
>> index 311cd93377c7..d5dd60530a24 100644
>> --- a/include/linux/libata.h
>> +++ b/include/linux/libata.h
>> @@ -1085,7 +1085,7 @@ bool ata_scsi_dma_need_drain(struct request *rq);
>>   #else
>>   #define ata_scsi_dma_need_drain NULL
>>   #endif
>> -extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct scsi_device 
>> *dev,
>> +extern int ata_sas_scsi_ioctl(struct ata_port *ap, struct ata_device 
>> *dev,
>>                   unsigned int cmd, void __user *arg);
>>   extern bool ata_link_online(struct ata_link *link);
>>   extern bool ata_link_offline(struct ata_link *link);
> 
> .