Re: [PATCH v3 09/19] nvme: Add pr_ops read_keys support

[Mike Christie <michael.christie@oracle.com>]

On 10/30/22 3:17 AM, Christoph Hellwig wrote:
> On Wed, Oct 26, 2022 at 06:19:35PM -0500, Mike Christie wrote:
>> This patch adds support for the pr_ops read_keys callout by calling the
>> NVMe Reservation Report helper, then parsing that info to get the
>> controller's registered keys. Because the callout is only used in the
>> kernel where the callers do not know about controller/host IDs, the
>> callout just returns the registered keys which is required by the SCSI PR
>> in READ KEYS command.
>>
>> Signed-off-by: Mike Christie <michael.christie@oracle.com>
>> ---
>>  drivers/nvme/host/pr.c | 73 ++++++++++++++++++++++++++++++++++++++++++
>>  include/linux/nvme.h   |  4 +++
>>  2 files changed, 77 insertions(+)
>>
>> diff --git a/drivers/nvme/host/pr.c b/drivers/nvme/host/pr.c
>> index aa88c55879b2..df7eb2440c67 100644
>> --- a/drivers/nvme/host/pr.c
>> +++ b/drivers/nvme/host/pr.c
>> @@ -118,10 +118,83 @@ static int nvme_pr_release(struct block_device *bdev, u64 key, enum pr_type type
>>  	return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_release);
>>  }
>>  
>> +static int nvme_pr_resv_report(struct block_device *bdev, u8 *data,
>> +		u32 data_len, bool *eds)
> 
> Is there any good reason this method seems to take a u8 instead of a void
> pointer?  As that seems to make a few things a bit messy.

I did it because the helper functions nvme_send_ns_head_pr_command/
nvme_send_ns_pr_command took a u8.

Looking at it some more I see those functions use nvme_submit_sync_cmd
which then takes a avoid pointer.

To handle your comment about the helper below I'll fix all that up to
take a void pointer.


> 
>> +	if (IS_ENABLED(CONFIG_NVME_MULTIPATH) &&
>> +	    bdev->bd_disk->fops == &nvme_ns_head_ops)
>> +		ret = nvme_send_ns_head_pr_command(bdev, &c, data, data_len);
>> +	else
>> +		ret = nvme_send_ns_pr_command(bdev->bd_disk->private_data, &c,
>> +					      data, data_len);
> 
> Can you please add a hlper for this logic?

Will do.

> 
>> +	for (i = 0; i < num_ret_keys; i++) {
>> +		if (eds) {
>> +			keys_info->keys[i] =
>> +					le64_to_cpu(status->regctl_eds[i].rkey);
>> +		} else {
>> +			keys_info->keys[i] =
>> +					le64_to_cpu(status->regctl_ds[i].rkey);
>> +		}
> 
> If you shorten the status variable name to something like rs this becomes
> much easier to follow :)


Will do.