Commit 97faec53 authored by James Smart's avatar James Smart Committed by Christoph Hellwig
Browse files

nvme_fc: add 'nvme_discovery' sysfs attribute to fc transport device 



The fc transport device should allow for a rediscovery, as userspace
might have lost the events. Example is udev events not handled during
system startup.

This patch add a sysfs entry 'nvme_discovery' on the fc class to
have it replay all udev discovery events for all local port/remote
port address pairs.

Signed-off-by: default avatarJames Smart <jsmart2021@gmail.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent ea96d649

drivers/nvme/host/fc.c

+95 −9
Original line number Diff line number Diff line
@@ -122,6 +122,7 @@ struct nvme_fc_rport { 
	struct list_head		endp_list; /* for lport->endp_list */

	struct list_head		ctrl_list;

	struct list_head		ls_req_list;

	struct list_head		disc_list;

	struct device			*dev;	/* physical device for dma */

	struct nvme_fc_lport		*lport;

	spinlock_t			lock;
@@ -210,7 +211,6 @@ static DEFINE_IDA(nvme_fc_ctrl_cnt); 
 * These items are short-term. They will eventually be moved into

 * a generic FC class. See comments in module init.

 */

static struct class *fc_class;

static struct device *fc_udev_device;
@@ -507,6 +507,7 @@ nvme_fc_free_rport(struct kref *ref) 
	list_del(&rport->endp_list);

	spin_unlock_irqrestore(&nvme_fc_lock, flags);



	WARN_ON(!list_empty(&rport->disc_list));

	ida_simple_remove(&lport->endp_cnt, rport->remoteport.port_num);



	kfree(rport);
@@ -694,6 +695,7 @@ nvme_fc_register_remoteport(struct nvme_fc_local_port *localport, 
	INIT_LIST_HEAD(&newrec->endp_list);

	INIT_LIST_HEAD(&newrec->ctrl_list);

	INIT_LIST_HEAD(&newrec->ls_req_list);

	INIT_LIST_HEAD(&newrec->disc_list);

	kref_init(&newrec->ref);

	atomic_set(&newrec->act_ctrl_cnt, 0);

	spin_lock_init(&newrec->lock);
@@ -3254,6 +3256,90 @@ static struct nvmf_transport_ops nvme_fc_transport = { 
	.create_ctrl	= nvme_fc_create_ctrl,

};



/* Arbitrary successive failures max. With lots of subsystems could be high */

#define DISCOVERY_MAX_FAIL	20



static ssize_t nvme_fc_nvme_discovery_store(struct device *dev,

		struct device_attribute *attr, const char *buf, size_t count)

{

	unsigned long flags;

	LIST_HEAD(local_disc_list);

	struct nvme_fc_lport *lport;

	struct nvme_fc_rport *rport;

	int failcnt = 0;



	spin_lock_irqsave(&nvme_fc_lock, flags);

restart:

	list_for_each_entry(lport, &nvme_fc_lport_list, port_list) {

		list_for_each_entry(rport, &lport->endp_list, endp_list) {

			if (!nvme_fc_lport_get(lport))

				continue;

			if (!nvme_fc_rport_get(rport)) {

				/*

				 * This is a temporary condition. Upon restart

				 * this rport will be gone from the list.

				 *

				 * Revert the lport put and retry.  Anything

				 * added to the list already will be skipped (as

				 * they are no longer list_empty).  Loops should

				 * resume at rports that were not yet seen.

				 */

				nvme_fc_lport_put(lport);



				if (failcnt++ < DISCOVERY_MAX_FAIL)

					goto restart;



				pr_err("nvme_discovery: too many reference "

				       "failures\n");

				goto process_local_list;

			}

			if (list_empty(&rport->disc_list))

				list_add_tail(&rport->disc_list,

					      &local_disc_list);

		}

	}



process_local_list:

	while (!list_empty(&local_disc_list)) {

		rport = list_first_entry(&local_disc_list,

					 struct nvme_fc_rport, disc_list);

		list_del_init(&rport->disc_list);

		spin_unlock_irqrestore(&nvme_fc_lock, flags);



		lport = rport->lport;

		/* signal discovery. Won't hurt if it repeats */

		nvme_fc_signal_discovery_scan(lport, rport);

		nvme_fc_rport_put(rport);

		nvme_fc_lport_put(lport);



		spin_lock_irqsave(&nvme_fc_lock, flags);

	}

	spin_unlock_irqrestore(&nvme_fc_lock, flags);



	return count;

}

static DEVICE_ATTR(nvme_discovery, 0200, NULL, nvme_fc_nvme_discovery_store);



static struct attribute *nvme_fc_attrs[] = {

	&dev_attr_nvme_discovery.attr,

	NULL

};



static struct attribute_group nvme_fc_attr_group = {

	.attrs = nvme_fc_attrs,

};



static const struct attribute_group *nvme_fc_attr_groups[] = {

	&nvme_fc_attr_group,

	NULL

};



static struct class fc_class = {

	.name = "fc",

	.dev_groups = nvme_fc_attr_groups,

	.owner = THIS_MODULE,

};



static int __init nvme_fc_init_module(void)

{

	int ret;
@@ -3272,16 +3358,16 @@ static int __init nvme_fc_init_module(void) 
	 * put in place, this code will move to a more generic

	 * location for the class.

	 */

	fc_class = class_create(THIS_MODULE, "fc");

	if (IS_ERR(fc_class)) {

	ret = class_register(&fc_class);

	if (ret) {

		pr_err("couldn't register class fc\n");

		return PTR_ERR(fc_class);

		return ret;

	}



	/*

	 * Create a device for the FC-centric udev events

	 */

	fc_udev_device = device_create(fc_class, NULL, MKDEV(0, 0), NULL,

	fc_udev_device = device_create(&fc_class, NULL, MKDEV(0, 0), NULL,

				"fc_udev_device");

	if (IS_ERR(fc_udev_device)) {

		pr_err("couldn't create fc_udev device!\n");
@@ -3296,9 +3382,9 @@ static int __init nvme_fc_init_module(void) 
	return 0;



out_destroy_device:

	device_destroy(fc_class, MKDEV(0, 0));

	device_destroy(&fc_class, MKDEV(0, 0));

out_destroy_class:

	class_destroy(fc_class);

	class_unregister(&fc_class);

	return ret;

}
@@ -3313,8 +3399,8 @@ static void __exit nvme_fc_exit_module(void) 
	ida_destroy(&nvme_fc_local_port_cnt);

	ida_destroy(&nvme_fc_ctrl_cnt);



	device_destroy(fc_class, MKDEV(0, 0));

	class_destroy(fc_class);

	device_destroy(&fc_class, MKDEV(0, 0));

	class_unregister(&fc_class);

}



module_init(nvme_fc_init_module);

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