Commit 8f75ba28 authored by Uday Shankar's avatar Uday Shankar Committed by Jens Axboe
Browse files

selftests: ublk: kublk: lift queue initialization out of thread 



Currently, each ublk server I/O handler thread initializes its own
queue. However, as we move towards decoupled ublk_queues and ublk server
threads, this model does not make sense anymore, as there will no longer
be a concept of a thread having "its own" queue. So lift queue
initialization out of the per-thread ublk_io_handler_fn and into a loop
in ublk_start_daemon (which runs once for each device).

There is a part of ublk_queue_init (ring initialization) which does
actually need to happen on the thread that will use the ring; that is
separated into a separate ublk_thread_init which is still called by each
I/O handler thread.

Signed-off-by: default avatarUday Shankar <ushankar@purestorage.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250529-ublk_task_per_io-v8-4-e9d3b119336a@purestorage.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 97737097

tools/testing/selftests/ublk/kublk.c

+47 −21
Original line number Diff line number Diff line
@@ -412,6 +412,17 @@ static void ublk_queue_deinit(struct ublk_queue *q) 
	int i;

	int nr_ios = q->q_depth;



	if (q->io_cmd_buf)

		munmap(q->io_cmd_buf, ublk_queue_cmd_buf_sz(q));



	for (i = 0; i < nr_ios; i++)

		free(q->ios[i].buf_addr);

}



static void ublk_thread_deinit(struct ublk_queue *q)

{

	q->tid = 0;



	io_uring_unregister_buffers(&q->ring);



	io_uring_unregister_ring_fd(&q->ring);
@@ -421,28 +432,20 @@ static void ublk_queue_deinit(struct ublk_queue *q) 
		close(q->ring.ring_fd);

		q->ring.ring_fd = -1;

	}



	if (q->io_cmd_buf)

		munmap(q->io_cmd_buf, ublk_queue_cmd_buf_sz(q));



	for (i = 0; i < nr_ios; i++)

		free(q->ios[i].buf_addr);

}



static int ublk_queue_init(struct ublk_queue *q, unsigned extra_flags)

{

	struct ublk_dev *dev = q->dev;

	int depth = dev->dev_info.queue_depth;

	int i, ret = -1;

	int i;

	int cmd_buf_size, io_buf_size;

	unsigned long off;

	int ring_depth = dev->tgt.sq_depth, cq_depth = dev->tgt.cq_depth;



	q->tgt_ops = dev->tgt.ops;

	q->state = 0;

	q->q_depth = depth;

	q->cmd_inflight = 0;

	q->tid = gettid();



	if (dev->dev_info.flags & (UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_AUTO_BUF_REG)) {

		q->state |= UBLKSRV_NO_BUF;
@@ -479,6 +482,22 @@ static int ublk_queue_init(struct ublk_queue *q, unsigned extra_flags) 
		}

	}



	return 0;

 fail:

	ublk_queue_deinit(q);

	ublk_err("ublk dev %d queue %d failed\n",

			dev->dev_info.dev_id, q->q_id);

	return -ENOMEM;

}



static int ublk_thread_init(struct ublk_queue *q)

{

	struct ublk_dev *dev = q->dev;

	int ring_depth = dev->tgt.sq_depth, cq_depth = dev->tgt.cq_depth;

	int ret;



	q->tid = gettid();



	ret = ublk_setup_ring(&q->ring, ring_depth, cq_depth,

			IORING_SETUP_COOP_TASKRUN |

			IORING_SETUP_SINGLE_ISSUER |
@@ -509,8 +528,8 @@ static int ublk_queue_init(struct ublk_queue *q, unsigned extra_flags) 


	return 0;

fail:

	ublk_queue_deinit(q);

	ublk_err("ublk dev %d queue %d failed\n",

	ublk_thread_deinit(q);

	ublk_err("ublk dev %d queue %d thread init failed\n",

			dev->dev_info.dev_id, q->q_id);

	return -ENOMEM;

}
@@ -778,7 +797,6 @@ struct ublk_queue_info { 
	struct ublk_queue 	*q;

	sem_t 			*queue_sem;

	cpu_set_t 		*affinity;

	unsigned char 		auto_zc_fallback;

};



static void *ublk_io_handler_fn(void *data)
@@ -786,15 +804,11 @@ static void *ublk_io_handler_fn(void *data) 
	struct ublk_queue_info *info = data;

	struct ublk_queue *q = info->q;

	int dev_id = q->dev->dev_info.dev_id;

	unsigned extra_flags = 0;

	int ret;



	if (info->auto_zc_fallback)

		extra_flags = UBLKSRV_AUTO_BUF_REG_FALLBACK;



	ret = ublk_queue_init(q, extra_flags);

	ret = ublk_thread_init(q);

	if (ret) {

		ublk_err("ublk dev %d queue %d init queue failed\n",

		ublk_err("ublk dev %d queue %d thread init failed\n",

				dev_id, q->q_id);

		return NULL;

	}
@@ -813,7 +827,7 @@ static void *ublk_io_handler_fn(void *data) 
	} while (1);



	ublk_dbg(UBLK_DBG_QUEUE, "ublk dev %d queue %d exited\n", dev_id, q->q_id);

	ublk_queue_deinit(q);

	ublk_thread_deinit(q);

	return NULL;

}
@@ -857,6 +871,7 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev) 
{

	const struct ublksrv_ctrl_dev_info *dinfo = &dev->dev_info;

	struct ublk_queue_info *qinfo;

	unsigned extra_flags = 0;

	cpu_set_t *affinity_buf;

	void *thread_ret;

	sem_t queue_sem;
@@ -878,14 +893,23 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev) 
	if (ret)

		return ret;



	if (ctx->auto_zc_fallback)

		extra_flags = UBLKSRV_AUTO_BUF_REG_FALLBACK;



	for (i = 0; i < dinfo->nr_hw_queues; i++) {

		dev->q[i].dev = dev;

		dev->q[i].q_id = i;



		ret = ublk_queue_init(&dev->q[i], extra_flags);

		if (ret) {

			ublk_err("ublk dev %d queue %d init queue failed\n",

				 dinfo->dev_id, i);

			goto fail;

		}



		qinfo[i].q = &dev->q[i];

		qinfo[i].queue_sem = &queue_sem;

		qinfo[i].affinity = &affinity_buf[i];

		qinfo[i].auto_zc_fallback = ctx->auto_zc_fallback;

		pthread_create(&dev->q[i].thread, NULL,

				ublk_io_handler_fn,

				&qinfo[i]);
@@ -918,6 +942,8 @@ static int ublk_start_daemon(const struct dev_ctx *ctx, struct ublk_dev *dev) 
	for (i = 0; i < dinfo->nr_hw_queues; i++)

		pthread_join(dev->q[i].thread, &thread_ret);

 fail:

	for (i = 0; i < dinfo->nr_hw_queues; i++)

		ublk_queue_deinit(&dev->q[i]);

	ublk_dev_unprep(dev);

	ublk_dbg(UBLK_DBG_DEV, "%s exit\n", __func__);