2023-05-03 18:44:21

by John Garry

Subject: [PATCH RFC 16/16] nvme: Support atomic writes

From: Alan Adamson <[email protected]>

Support reading atomic write registers to fill in request_queue
properties.

Use following method to calculate limits:
atomic_write_max_bytes = flp2(NAWUPF ?: AWUPF)
atomic_write_unit_min = logical_block_size
atomic_write_unit_max = flp2(NAWUPF ?: AWUPF)
atomic_write_boundary = NABSPF

Signed-off-by: Alan Adamson <[email protected]>
Signed-off-by: John Garry <[email protected]>
---
drivers/nvme/host/core.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index d6a9bac91a4c..289561915ad3 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1879,6 +1879,39 @@ 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 (!(boundary & (boundary - 1))) {
+ blk_queue_atomic_write_max_bytes(disk->queue,
+ atomic_bs);
+ blk_queue_atomic_write_unit_min(disk->queue, 1);
+ blk_queue_atomic_write_unit_max(disk->queue,
+ atomic_bs / bs);
+ blk_queue_atomic_write_boundary(disk->queue,
+ boundary);
+ } else {
+ dev_err(ns->ctrl->device, "Unsupported atomic boundary=0x%x\n",
+ boundary);
+ }
+ }
+ } else if (ns->ctrl->subsys->awupf) {
+ blk_queue_atomic_write_max_bytes(disk->queue,
+ atomic_bs);
+ blk_queue_atomic_write_unit_min(disk->queue, 1);
+ blk_queue_atomic_write_unit_max(disk->queue,
+ atomic_bs / bs);
+ blk_queue_atomic_write_boundary(disk->queue, 0);
+ }
+
/*
* Register a metadata profile for PI, or the plain non-integrity NVMe
* metadata masquerading as Type 0 if supported, otherwise reject block
--
2.31.1

2023-05-03 18:54:43

by Bart Van Assche

Subject: Re: [PATCH RFC 16/16] nvme: Support atomic writes

On 5/3/23 11:38, John Garry wrote:
> + if (!(boundary & (boundary - 1))) {

Please use is_power_of_2() instead of open-coding it.

Thanks,

Bart.

2023-05-04 08:29:28

by John Garry

Subject: Re: [PATCH RFC 16/16] nvme: Support atomic writes

On 03/05/2023 19:49, Bart Van Assche wrote:
> On 5/3/23 11:38, John Garry wrote:
>> +            if (!(boundary & (boundary - 1))) {
>
> Please use is_power_of_2() instead of open-coding it.

Sure, that can be changed, thanks