Re: [PATCH 21/21] nvme: Support atomic writes

John Garry
2023-10-05T15:45:43Z

On 04/10/2023 12:39, Pankaj Raghav wrote:
>> +++ b/drivers/nvme/host/core.c
>> @@ -1926,6 +1926,35 @@ static void nvme_update_disk_info(struct gendisk *disk,
>> blk_queue_io_min(disk->queue, phys_bs);
>> blk_queue_io_opt(disk->queue, io_opt);
>>
>> + atomic_bs = rounddown_pow_of_two(atomic_bs);
>> + if (id->nsfeat & NVME_NS_FEAT_ATOMICS && id->nawupf) {
>> + if (id->nabo) {
>> + dev_err(ns->ctrl->device, "Support atomic NABO=%x\n",
>> + id->nabo);
>> + } else {
>> + u32 boundary = 0;
>> +
>> + if (le16_to_cpu(id->nabspf))
>> + boundary = (le16_to_cpu(id->nabspf) + 1) * bs;
>> +
>> + if (is_power_of_2(boundary) || !boundary) {

note to self/Alan: boundary just needs to be multiple of atomic write
unit max, and not necessarily a power-of-2

>> + blk_queue_atomic_write_max_bytes(disk->queue, atomic_bs);
>> + blk_queue_atomic_write_unit_min_sectors(disk->queue, 1);
>> + blk_queue_atomic_write_unit_max_sectors(disk->queue,
>> + atomic_bs / bs);
> blk_queue_atomic_write_unit_[min| max]_sectors expects sectors (512 bytes unit)
> as input but no conversion is done here from device logical block size
> to SECTORs.

Yeah, you are right. I think that we can just use:

blk_queue_atomic_write_unit_max_sectors(disk->queue,
atomic_bs >> SECTOR_SHIFT);

Thanks,
John

>> + blk_queue_atomic_write_boundary_bytes(disk->queue, boundary);
>> + } else {
>> + dev_err(ns->ctrl->device, "Unsupported atomic boundary=0x%x\n",
>> + boundary);
>> + }
>>