2021-01-27 21:02:04

by Asutosh Das (asd)

Subject: [RFC PATCH v1 1/2] block: bsg: resume scsi device before accessing

Resumes the scsi device before accessing it.

Change-Id: I2929af60f2a92c89704a582fcdb285d35b429fde
Signed-off-by: Asutosh Das <[email protected]>
Signed-off-by: Can Guo <[email protected]>
Signed-off-by: Bao D. Nguyen <[email protected]>
---
block/bsg.c | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/block/bsg.c b/block/bsg.c
index d7bae94..f4c197f 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -306,12 +306,16 @@ static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file)
static int bsg_open(struct inode *inode, struct file *file)
{
struct bsg_device *bd;
+ struct scsi_device *sd;

bd = bsg_get_device(inode, file);

if (IS_ERR(bd))
return PTR_ERR(bd);

+ sd = (struct scsi_device *) bd->queue->queuedata;
+ if (scsi_autopm_get_device(sd))
+ return -EIO;
file->private_data = bd;
return 0;
}
@@ -319,8 +323,12 @@ static int bsg_open(struct inode *inode, struct file *file)
static int bsg_release(struct inode *inode, struct file *file)
{
struct bsg_device *bd = file->private_data;
+ struct scsi_device *sd;

file->private_data = NULL;
+ sd = (struct scsi_device *) bd->queue->queuedata;
+ scsi_autopm_put_device(sd);
+
return bsg_put_device(bd);
}

--
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2021-01-27 21:32:59

by Avri Altman

Subject: RE: [RFC PATCH v1 1/2] block: bsg: resume scsi device before accessing

>
> Resumes the scsi device before accessing it.
>
> Change-Id: I2929af60f2a92c89704a582fcdb285d35b429fde
> Signed-off-by: Asutosh Das <[email protected]>
> Signed-off-by: Can Guo <[email protected]>
> Signed-off-by: Bao D. Nguyen <[email protected]>
Following this patch, is it possible to revert commit 74e5e468b664d?

Thanks,
Avri

2021-01-27 21:38:19

by Can Guo

Subject: Re: [RFC PATCH v1 1/2] block: bsg: resume scsi device before accessing

On 2021-01-27 15:09, Avri Altman wrote:
>>
>> Resumes the scsi device before accessing it.
>>
>> Change-Id: I2929af60f2a92c89704a582fcdb285d35b429fde
>> Signed-off-by: Asutosh Das <[email protected]>
>> Signed-off-by: Can Guo <[email protected]>
>> Signed-off-by: Bao D. Nguyen <[email protected]>
> Following this patch, is it possible to revert commit 74e5e468b664d?
>

No, but this is a good finding... This change assumes
that the queue->queue_data is a scsi_device, which is
why we call scsi_auto_pm_get(). But for ufs_bsg's case,
queue->queue_data is a device...

Thanks,
Can Guo.

> Thanks,
> Avri

2021-01-27 21:40:58

by Can Guo

Subject: Re: [RFC PATCH v1 1/2] block: bsg: resume scsi device before accessing

On 2021-01-27 15:59, Can Guo wrote:
> On 2021-01-27 15:09, Avri Altman wrote:
>>>
>>> Resumes the scsi device before accessing it.
>>>
>>> Change-Id: I2929af60f2a92c89704a582fcdb285d35b429fde
>>> Signed-off-by: Asutosh Das <[email protected]>
>>> Signed-off-by: Can Guo <[email protected]>
>>> Signed-off-by: Bao D. Nguyen <[email protected]>
>> Following this patch, is it possible to revert commit 74e5e468b664d?
>>
>
> No, but this is a good finding... This change assumes
> that the queue->queue_data is a scsi_device, which is
> why we call scsi_auto_pm_get(). But for ufs_bsg's case,
> queue->queue_data is a device...
>

If we call pm_runtime_get/put_sync(bcd->class_dev->parent) in
bsg_get/put_device(), commit 74e5e468b664d can be reverted.
This is just a rough idea.

> Thanks,
> Can Guo.
>
>> Thanks,
>> Avri

2021-02-07 02:27:42

by Bart Van Assche

Subject: Re: [RFC PATCH v1 1/2] block: bsg: resume scsi device before accessing

On 1/26/21 8:00 PM, Asutosh Das wrote:
> Resumes the scsi device before accessing it.
>
> Change-Id: I2929af60f2a92c89704a582fcdb285d35b429fde
> Signed-off-by: Asutosh Das <[email protected]>
> Signed-off-by: Can Guo <[email protected]>
> Signed-off-by: Bao D. Nguyen <[email protected]>

No Change-Id tags in upstream patches please.

Thanks,

Bart.