Re: [PATCH v4 2/2] ublk: add UBLK_CMD_TRY_STOP_DEV command

[Yoav Cohen <yoav@nvidia.com>]

On 18/01/2026 16:06, Alexander Atanasov wrote:
> External email: Use caution opening links or attachments
> 
> 
> On 6.01.26 22:33, Yoav Cohen wrote:
>> This command is similar to UBLK_CMD_STOP_DEV, but it only stops the
>> device if there are no active openers for the ublk block device.
>> If the device is busy, the command returns -EBUSY instead of
>> disrupting active clients. This allows safe, non-destructive stopping.
>>
>> Advertise UBLK_CMD_TRY_STOP_DEV support via UBLK_F_SAFE_STOP_DEV
>> feature flag.
>>
>> Signed-off-by: Yoav Cohen <yoav@nvidia.com>
>> ---
>>   drivers/block/ublk_drv.c             | 44 ++++++++++++++++++++++++++--
>>   include/uapi/linux/ublk_cmd.h        |  9 +++++-
>>   tools/testing/selftests/ublk/kublk.c |  1 +
>>   3 files changed, 51 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index 2d5602ef05cc..fc8b87902f8f 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -54,6 +54,7 @@
>>   #define UBLK_CMD_DEL_DEV_ASYNC      _IOC_NR(UBLK_U_CMD_DEL_DEV_ASYNC)
> [snip]
> 
> 
>> @@ -919,6 +923,9 @@ static int ublk_open(struct gendisk *disk, 
>> blk_mode_t mode)
>>                       return -EPERM;
>>       }
>>
>> +     if (ub->block_open)
>> +             return -EBUSY;
>> +
> 
> Why back to EBUSY?
> 
> 
This is an old patch version - v7 was already pushed with your comments 
applied(-ENXIO)