1 /* 2 * Copyright(c) 2013-2015 Intel Corporation. All rights reserved. 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of version 2 of the GNU General Public License as 6 * published by the Free Software Foundation. 7 * 8 * This program is distributed in the hope that it will be useful, but 9 * WITHOUT ANY WARRANTY; without even the implied warranty of 10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 * General Public License for more details. 12 */ 13 #include <linux/cpumask.h> 14 #include <linux/module.h> 15 #include <linux/device.h> 16 #include <linux/nd.h> 17 #include "nd.h" 18 19 static int nd_region_probe(struct device *dev) 20 { 21 int err; 22 static unsigned long once; 23 struct nd_region_namespaces *num_ns; 24 struct nd_region *nd_region = to_nd_region(dev); 25 int rc = nd_region_register_namespaces(nd_region, &err); 26 27 if (nd_region->num_lanes > num_online_cpus() 28 && nd_region->num_lanes < num_possible_cpus() 29 && !test_and_set_bit(0, &once)) { 30 dev_info(dev, "online cpus (%d) < concurrent i/o lanes (%d) < possible cpus (%d)\n", 31 num_online_cpus(), nd_region->num_lanes, 32 num_possible_cpus()); 33 dev_info(dev, "setting nr_cpus=%d may yield better libnvdimm device performance\n", 34 nd_region->num_lanes); 35 } 36 37 num_ns = devm_kzalloc(dev, sizeof(*num_ns), GFP_KERNEL); 38 if (!num_ns) 39 return -ENOMEM; 40 41 if (rc < 0) 42 return rc; 43 44 num_ns->active = rc; 45 num_ns->count = rc + err; 46 dev_set_drvdata(dev, num_ns); 47 48 if (rc && err && rc == err) 49 return -ENODEV; 50 51 nd_region->btt_seed = nd_btt_create(nd_region); 52 if (err == 0) 53 return 0; 54 55 /* 56 * Given multiple namespaces per region, we do not want to 57 * disable all the successfully registered peer namespaces upon 58 * a single registration failure. If userspace is missing a 59 * namespace that it expects it can disable/re-enable the region 60 * to retry discovery after correcting the failure. 61 * <regionX>/namespaces returns the current 62 * "<async-registered>/<total>" namespace count. 63 */ 64 dev_err(dev, "failed to register %d namespace%s, continuing...\n", 65 err, err == 1 ? "" : "s"); 66 return 0; 67 } 68 69 static int child_unregister(struct device *dev, void *data) 70 { 71 nd_device_unregister(dev, ND_SYNC); 72 return 0; 73 } 74 75 static int nd_region_remove(struct device *dev) 76 { 77 struct nd_region *nd_region = to_nd_region(dev); 78 79 /* flush attribute readers and disable */ 80 nvdimm_bus_lock(dev); 81 nd_region->ns_seed = NULL; 82 nd_region->btt_seed = NULL; 83 dev_set_drvdata(dev, NULL); 84 nvdimm_bus_unlock(dev); 85 86 device_for_each_child(dev, NULL, child_unregister); 87 return 0; 88 } 89 90 static struct nd_device_driver nd_region_driver = { 91 .probe = nd_region_probe, 92 .remove = nd_region_remove, 93 .drv = { 94 .name = "nd_region", 95 }, 96 .type = ND_DRIVER_REGION_BLK | ND_DRIVER_REGION_PMEM, 97 }; 98 99 int __init nd_region_init(void) 100 { 101 return nd_driver_register(&nd_region_driver); 102 } 103 104 void nd_region_exit(void) 105 { 106 driver_unregister(&nd_region_driver.drv); 107 } 108 109 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_PMEM); 110 MODULE_ALIAS_ND_DEVICE(ND_DEVICE_REGION_BLK); 111