Re: [PATCH 4/4] nvme: add support for mq_ops->queue_rqs()

Jens Axboe
2021-12-16T16:27:22Z

On 12/16/21 9:15 AM, Christoph Hellwig wrote:
> On Thu, Dec 16, 2021 at 08:45:46AM -0700, Jens Axboe wrote:
>> On 12/16/21 2:08 AM, Christoph Hellwig wrote:
>>> On Wed, Dec 15, 2021 at 09:24:21AM -0700, Jens Axboe wrote:
>>>> + spin_lock(&nvmeq->sq_lock);
>>>> + while (!rq_list_empty(*rqlist)) {
>>>> + struct request *req = rq_list_pop(rqlist);
>>>> + struct nvme_iod *iod = blk_mq_rq_to_pdu(req);
>>>> +
>>>> + memcpy(nvmeq->sq_cmds + (nvmeq->sq_tail << nvmeq->sqes),
>>>> + absolute_pointer(&iod->cmd), sizeof(iod->cmd));
>>>> + if (++nvmeq->sq_tail == nvmeq->q_depth)
>>>> + nvmeq->sq_tail = 0;
>>>
>>> So this doesn't even use the new helper added in patch 2? I think this
>>> should call nvme_sq_copy_cmd().
>>
>> But you NAK'ed that one? It definitely should use that helper, so I take it
>> you are fine with it then if we do it here too? That would make 3 call sites,
>> and I still do think the helper makes sense...
>
> I explained two times that the new helpers is fine as long as you open
> code nvme_submit_cmd in its two callers as it now is a trivial wrapper.

OK, I misunderstood which one you referred to then. So this incremental,
I'll send out a new series...

diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index 58d97660374a..51a903d91d92 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -509,21 +509,6 @@ static inline void nvme_sq_copy_cmd(struct nvme_queue *nvmeq,
nvmeq->sq_tail = 0;
}

-/**
- * nvme_submit_cmd() - Copy a command into a queue and ring the doorbell
- * @nvmeq: The queue to use
- * @cmd: The command to send
- * @write_sq: whether to write to the SQ doorbell
- */
-static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd,
- bool write_sq)
-{
- spin_lock(&nvmeq->sq_lock);
- nvme_sq_copy_cmd(nvmeq, cmd);
- nvme_write_sq_db(nvmeq, write_sq);
- spin_unlock(&nvmeq->sq_lock);
-}
-
static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx)
{
struct nvme_queue *nvmeq = hctx->driver_data;
@@ -977,7 +962,10 @@ static blk_status_t nvme_queue_rq(struct blk_mq_hw_ctx *hctx,
ret = nvme_prep_rq(dev, req);
if (unlikely(ret))
return ret;
- nvme_submit_cmd(nvmeq, &iod->cmd, bd->last);
+ spin_lock(&nvmeq->sq_lock);
+ nvme_sq_copy_cmd(nvmeq, &iod->cmd);
+ nvme_write_sq_db(nvmeq, bd->last);
+ spin_unlock(&nvmeq->sq_lock);
return BLK_STS_OK;
}

@@ -1213,7 +1201,11 @@ static void nvme_pci_submit_async_event(struct nvme_ctrl *ctrl)

c.common.opcode = nvme_admin_async_event;
c.common.command_id = NVME_AQ_BLK_MQ_DEPTH;
- nvme_submit_cmd(nvmeq, &c, true);
+
+ spin_lock(&nvmeq->sq_lock);
+ nvme_sq_copy_cmd(nvmeq, &c);
+ nvme_write_sq_db(nvmeq, true);
+ spin_unlock(&nvmeq->sq_lock);
}

static int adapter_delete_queue(struct nvme_dev *dev, u8 opcode, u16 id)

--
Jens Axboe