From 97faec531460c949d7120672b8c77e2f41f8d6d7 Mon Sep 17 00:00:00 2001 From: James Smart Date: Thu, 13 Sep 2018 16:17:38 -0700 Subject: 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: James Smart Signed-off-by: Christoph Hellwig --- drivers/nvme/host/fc.c | 104 ++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 95 insertions(+), 9 deletions(-) (limited to 'drivers/nvme') diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c index fd700073d312..9d201b35397d 100644 --- a/drivers/nvme/host/fc.c +++ b/drivers/nvme/host/fc.c @@ -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); -- cgit v1.2.3