Re: [PATCH 1/2] scsi: core: Fix sbitmap depth in scsi_realloc_sdev_budget_map()

John Garry
2022-03-15T15:11:19Z

On 15/03/2022 14:33, Bart Van Assche wrote:
>> sbitmap sb_backup;
>> +    depth = min_t(unsigned int, depth,
>> scsi_device_max_queue_depth(sdev));
>> +
>>       /*
>>        * realloc if new shift is calculated, which is caused by setting
>>        * up one new default queue depth after calling ->slave_configure
>> @@ -245,6 +247,9 @@ static int scsi_realloc_sdev_budget_map(struct
>> scsi_device *sdev,
>>                   scsi_device_max_queue_depth(sdev),
>>                   new_shift, GFP_KERNEL,
>>                   sdev->request_queue->node, false, true);
>> +    if (!ret)
>> +        sbitmap_resize(&sdev->budget_map, depth);
>
> Hmm ... why to call both sbitmap_init_node() and sbitmap_resize()
> instead of combining both calls into a single call with the proper depth?

Hi Bart,

Is the user wants to change the queue depth later via sysfs we do not
reallocate the sbitmap then. So we need to ensure that the size we
reallocate here will satisfy the scsi device max depth. I'm referencing
scsi_change_queue_depth() for this.

Thanks,
John