Commit a2f4c1ae authored by Uday Shankar's avatar Uday Shankar Committed by Jens Axboe
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selftests: ublk: kublk: improve behavior on init failure 



Some failure modes are handled poorly by kublk. For example, if ublk_drv
is built as a module but not currently loaded into the kernel, ./kublk
add ... just hangs forever. This happens because in this case (and a few
others), the worker process does not notify its parent (via a write to
the shared eventfd) that it has tried and failed to initialize, so the
parent hangs forever. Fix this by ensuring that we always notify the
parent process of any initialization failure, and have the parent print
a (not very descriptive) log line when this happens.

Signed-off-by: default avatarUday Shankar <ushankar@purestorage.com>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250603-ublk_init_fail-v1-1-87c91486230e@purestorage.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 43a67dd8

tools/testing/selftests/ublk/kublk.c

+23 −11
Original line number Diff line number Diff line
@@ -1112,7 +1112,7 @@ static int __cmd_dev_add(const struct dev_ctx *ctx) 
	__u64 features;

	const struct ublk_tgt_ops *ops;

	struct ublksrv_ctrl_dev_info *info;

	struct ublk_dev *dev;

	struct ublk_dev *dev = NULL;

	int dev_id = ctx->dev_id;

	int ret, i;
@@ -1120,13 +1120,15 @@ static int __cmd_dev_add(const struct dev_ctx *ctx) 
	if (!ops) {

		ublk_err("%s: no such tgt type, type %s\n",

				__func__, tgt_type);

		return -ENODEV;

		ret = -ENODEV;

		goto fail;

	}



	if (nr_queues > UBLK_MAX_QUEUES || depth > UBLK_QUEUE_DEPTH) {

		ublk_err("%s: invalid nr_queues or depth queues %u depth %u\n",

				__func__, nr_queues, depth);

		return -EINVAL;

		ret = -EINVAL;

		goto fail;

	}



	/* default to 1:1 threads:queues if nthreads is unspecified */
@@ -1136,30 +1138,37 @@ static int __cmd_dev_add(const struct dev_ctx *ctx) 
	if (nthreads > UBLK_MAX_THREADS) {

		ublk_err("%s: %u is too many threads (max %u)\n",

				__func__, nthreads, UBLK_MAX_THREADS);

		return -EINVAL;

		ret = -EINVAL;

		goto fail;

	}



	if (nthreads != nr_queues && !ctx->per_io_tasks) {

		ublk_err("%s: threads %u must be same as queues %u if "

			"not using per_io_tasks\n",

			__func__, nthreads, nr_queues);

		return -EINVAL;

		ret = -EINVAL;

		goto fail;

	}



	dev = ublk_ctrl_init();

	if (!dev) {

		ublk_err("%s: can't alloc dev id %d, type %s\n",

				__func__, dev_id, tgt_type);

		return -ENOMEM;

		ret = -ENOMEM;

		goto fail;

	}



	/* kernel doesn't support get_features */

	ret = ublk_ctrl_get_features(dev, &features);

	if (ret < 0)

		return -EINVAL;

	if (ret < 0) {

		ret = -EINVAL;

		goto fail;

	}



	if (!(features & UBLK_F_CMD_IOCTL_ENCODE))

		return -ENOTSUP;

	if (!(features & UBLK_F_CMD_IOCTL_ENCODE)) {

		ret = -ENOTSUP;

		goto fail;

	}



	info = &dev->dev_info;

	info->dev_id = ctx->dev_id;
@@ -1200,6 +1209,7 @@ static int __cmd_dev_add(const struct dev_ctx *ctx) 
fail:

	if (ret < 0)

		ublk_send_dev_event(ctx, dev, -1);

	if (dev)

		ublk_ctrl_deinit(dev);

	return ret;

}
@@ -1262,6 +1272,8 @@ static int cmd_dev_add(struct dev_ctx *ctx) 
		shmctl(ctx->_shmid, IPC_RMID, NULL);

		/* wait for child and detach from it */

		wait(NULL);

		if (exit_code == EXIT_FAILURE)

			ublk_err("%s: command failed\n", __func__);

		exit(exit_code);

	} else {

		exit(EXIT_FAILURE);