1 /*
2  * SCSI RDMA (SRP) transport class
3  *
4  * Copyright (C) 2007 FUJITA Tomonori <tomof@acm.org>
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License as
8  * published by the Free Software Foundation, version 2 of the
9  * License.
10  *
11  * This program is distributed in the hope that it will be useful, but
12  * WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14  * General Public License for more details.
15  *
16  * You should have received a copy of the GNU General Public License
17  * along with this program; if not, write to the Free Software
18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
19  * 02110-1301 USA
20  */
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/jiffies.h>
24 #include <linux/err.h>
25 #include <linux/slab.h>
26 #include <linux/string.h>
27 
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_device.h>
30 #include <scsi/scsi_host.h>
31 #include <scsi/scsi_transport.h>
32 #include <scsi/scsi_transport_srp.h>
33 #include "scsi_transport_srp_internal.h"
34 
35 struct srp_host_attrs {
36 	atomic_t next_port_id;
37 };
38 #define to_srp_host_attrs(host)	((struct srp_host_attrs *)(host)->shost_data)
39 
40 #define SRP_HOST_ATTRS 0
41 #define SRP_RPORT_ATTRS 2
42 
43 struct srp_internal {
44 	struct scsi_transport_template t;
45 	struct srp_function_template *f;
46 
47 	struct class_device_attribute *host_attrs[SRP_HOST_ATTRS + 1];
48 
49 	struct class_device_attribute *rport_attrs[SRP_RPORT_ATTRS + 1];
50 	struct class_device_attribute private_rport_attrs[SRP_RPORT_ATTRS];
51 	struct transport_container rport_attr_cont;
52 };
53 
54 #define to_srp_internal(tmpl) container_of(tmpl, struct srp_internal, t)
55 
56 #define	dev_to_rport(d)	container_of(d, struct srp_rport, dev)
57 #define transport_class_to_srp_rport(cdev) dev_to_rport((cdev)->dev)
58 
59 static int srp_host_setup(struct transport_container *tc, struct device *dev,
60 			  struct class_device *cdev)
61 {
62 	struct Scsi_Host *shost = dev_to_shost(dev);
63 	struct srp_host_attrs *srp_host = to_srp_host_attrs(shost);
64 
65 	atomic_set(&srp_host->next_port_id, 0);
66 	return 0;
67 }
68 
69 static DECLARE_TRANSPORT_CLASS(srp_host_class, "srp_host", srp_host_setup,
70 			       NULL, NULL);
71 
72 static DECLARE_TRANSPORT_CLASS(srp_rport_class, "srp_remote_ports",
73 			       NULL, NULL, NULL);
74 
75 #define SETUP_TEMPLATE(attrb, field, perm, test, ro_test, ro_perm)	\
76 	i->private_##attrb[count] = class_device_attr_##field;		\
77 	i->private_##attrb[count].attr.mode = perm;			\
78 	if (ro_test) {							\
79 		i->private_##attrb[count].attr.mode = ro_perm;		\
80 		i->private_##attrb[count].store = NULL;			\
81 	}								\
82 	i->attrb[count] = &i->private_##attrb[count];			\
83 	if (test)							\
84 		count++
85 
86 #define SETUP_RPORT_ATTRIBUTE_RD(field)					\
87 	SETUP_TEMPLATE(rport_attrs, field, S_IRUGO, 1, 0, 0)
88 
89 #define SETUP_RPORT_ATTRIBUTE_RW(field)					\
90 	SETUP_TEMPLATE(rport_attrs, field, S_IRUGO | S_IWUSR,		\
91 		       1, 1, S_IRUGO)
92 
93 #define SRP_PID(p) \
94 	(p)->port_id[0], (p)->port_id[1], (p)->port_id[2], (p)->port_id[3], \
95 	(p)->port_id[4], (p)->port_id[5], (p)->port_id[6], (p)->port_id[7], \
96 	(p)->port_id[8], (p)->port_id[9], (p)->port_id[10], (p)->port_id[11], \
97 	(p)->port_id[12], (p)->port_id[13], (p)->port_id[14], (p)->port_id[15]
98 
99 #define SRP_PID_FMT "%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x:" \
100 	"%02x:%02x:%02x:%02x:%02x:%02x:%02x:%02x"
101 
102 static ssize_t
103 show_srp_rport_id(struct class_device *cdev, char *buf)
104 {
105 	struct srp_rport *rport = transport_class_to_srp_rport(cdev);
106 	return sprintf(buf, SRP_PID_FMT "\n", SRP_PID(rport));
107 }
108 
109 static CLASS_DEVICE_ATTR(port_id, S_IRUGO, show_srp_rport_id, NULL);
110 
111 static const struct {
112 	u32 value;
113 	char *name;
114 } srp_rport_role_names[] = {
115 	{SRP_RPORT_ROLE_INITIATOR, "SRP Initiator"},
116 	{SRP_RPORT_ROLE_TARGET, "SRP Target"},
117 };
118 
119 static ssize_t
120 show_srp_rport_roles(struct class_device *cdev, char *buf)
121 {
122 	struct srp_rport *rport = transport_class_to_srp_rport(cdev);
123 	int i;
124 	char *name = NULL;
125 
126 	for (i = 0; i < ARRAY_SIZE(srp_rport_role_names); i++)
127 		if (srp_rport_role_names[i].value == rport->roles) {
128 			name = srp_rport_role_names[i].name;
129 			break;
130 		}
131 	return sprintf(buf, "%s\n", name ? : "unknown");
132 }
133 
134 static CLASS_DEVICE_ATTR(roles, S_IRUGO, show_srp_rport_roles, NULL);
135 
136 static void srp_rport_release(struct device *dev)
137 {
138 	struct srp_rport *rport = dev_to_rport(dev);
139 
140 	put_device(dev->parent);
141 	kfree(rport);
142 }
143 
144 static int scsi_is_srp_rport(const struct device *dev)
145 {
146 	return dev->release == srp_rport_release;
147 }
148 
149 static int srp_rport_match(struct attribute_container *cont,
150 			   struct device *dev)
151 {
152 	struct Scsi_Host *shost;
153 	struct srp_internal *i;
154 
155 	if (!scsi_is_srp_rport(dev))
156 		return 0;
157 
158 	shost = dev_to_shost(dev->parent);
159 	if (!shost->transportt)
160 		return 0;
161 	if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
162 		return 0;
163 
164 	i = to_srp_internal(shost->transportt);
165 	return &i->rport_attr_cont.ac == cont;
166 }
167 
168 static int srp_host_match(struct attribute_container *cont, struct device *dev)
169 {
170 	struct Scsi_Host *shost;
171 	struct srp_internal *i;
172 
173 	if (!scsi_is_host_device(dev))
174 		return 0;
175 
176 	shost = dev_to_shost(dev);
177 	if (!shost->transportt)
178 		return 0;
179 	if (shost->transportt->host_attrs.ac.class != &srp_host_class.class)
180 		return 0;
181 
182 	i = to_srp_internal(shost->transportt);
183 	return &i->t.host_attrs.ac == cont;
184 }
185 
186 /**
187  * srp_rport_add - add a SRP remote port to the device hierarchy
188  * @shost:	scsi host the remote port is connected to.
189  * @ids:	The port id for the remote port.
190  *
191  * Publishes a port to the rest of the system.
192  */
193 struct srp_rport *srp_rport_add(struct Scsi_Host *shost,
194 				struct srp_rport_identifiers *ids)
195 {
196 	struct srp_rport *rport;
197 	struct device *parent = &shost->shost_gendev;
198 	int id, ret;
199 
200 	rport = kzalloc(sizeof(*rport), GFP_KERNEL);
201 	if (!rport)
202 		return ERR_PTR(-ENOMEM);
203 
204 	device_initialize(&rport->dev);
205 
206 	rport->dev.parent = get_device(parent);
207 	rport->dev.release = srp_rport_release;
208 
209 	memcpy(rport->port_id, ids->port_id, sizeof(rport->port_id));
210 	rport->roles = ids->roles;
211 
212 	id = atomic_inc_return(&to_srp_host_attrs(shost)->next_port_id);
213 	sprintf(rport->dev.bus_id, "port-%d:%d", shost->host_no, id);
214 
215 	transport_setup_device(&rport->dev);
216 
217 	ret = device_add(&rport->dev);
218 	if (ret) {
219 		transport_destroy_device(&rport->dev);
220 		put_device(&rport->dev);
221 		return ERR_PTR(ret);
222 	}
223 
224 	if (shost->active_mode & MODE_TARGET &&
225 	    ids->roles == SRP_RPORT_ROLE_INITIATOR) {
226 		ret = srp_tgt_it_nexus_create(shost, (unsigned long)rport,
227 					      rport->port_id);
228 		if (ret) {
229 			device_del(&rport->dev);
230 			transport_destroy_device(&rport->dev);
231 			put_device(&rport->dev);
232 			return ERR_PTR(ret);
233 		}
234 	}
235 
236 	transport_add_device(&rport->dev);
237 	transport_configure_device(&rport->dev);
238 
239 	return rport;
240 }
241 EXPORT_SYMBOL_GPL(srp_rport_add);
242 
243 /**
244  * srp_rport_del  -  remove a SRP remote port
245  * @rport:	SRP remote port to remove
246  *
247  * Removes the specified SRP remote port.
248  */
249 void srp_rport_del(struct srp_rport *rport)
250 {
251 	struct device *dev = &rport->dev;
252 	struct Scsi_Host *shost = dev_to_shost(dev->parent);
253 
254 	if (shost->active_mode & MODE_TARGET &&
255 	    rport->roles == SRP_RPORT_ROLE_INITIATOR)
256 		srp_tgt_it_nexus_destroy(shost, (unsigned long)rport);
257 
258 	transport_remove_device(dev);
259 	device_del(dev);
260 	transport_destroy_device(dev);
261 	put_device(dev);
262 }
263 EXPORT_SYMBOL_GPL(srp_rport_del);
264 
265 static int do_srp_rport_del(struct device *dev, void *data)
266 {
267 	if (scsi_is_srp_rport(dev))
268 		srp_rport_del(dev_to_rport(dev));
269 	return 0;
270 }
271 
272 /**
273  * srp_remove_host  -  tear down a Scsi_Host's SRP data structures
274  * @shost:	Scsi Host that is torn down
275  *
276  * Removes all SRP remote ports for a given Scsi_Host.
277  * Must be called just before scsi_remove_host for SRP HBAs.
278  */
279 void srp_remove_host(struct Scsi_Host *shost)
280 {
281 	device_for_each_child(&shost->shost_gendev, NULL, do_srp_rport_del);
282 }
283 EXPORT_SYMBOL_GPL(srp_remove_host);
284 
285 static int srp_tsk_mgmt_response(struct Scsi_Host *shost, u64 nexus, u64 tm_id,
286 				 int result)
287 {
288 	struct srp_internal *i = to_srp_internal(shost->transportt);
289 	return i->f->tsk_mgmt_response(shost, nexus, tm_id, result);
290 }
291 
292 static int srp_it_nexus_response(struct Scsi_Host *shost, u64 nexus, int result)
293 {
294 	struct srp_internal *i = to_srp_internal(shost->transportt);
295 	return i->f->it_nexus_response(shost, nexus, result);
296 }
297 
298 /**
299  * srp_attach_transport  -  instantiate SRP transport template
300  * @ft:		SRP transport class function template
301  */
302 struct scsi_transport_template *
303 srp_attach_transport(struct srp_function_template *ft)
304 {
305 	int count;
306 	struct srp_internal *i;
307 
308 	i = kzalloc(sizeof(*i), GFP_KERNEL);
309 	if (!i)
310 		return NULL;
311 
312 	i->t.tsk_mgmt_response = srp_tsk_mgmt_response;
313 	i->t.it_nexus_response = srp_it_nexus_response;
314 
315 	i->t.host_size = sizeof(struct srp_host_attrs);
316 	i->t.host_attrs.ac.attrs = &i->host_attrs[0];
317 	i->t.host_attrs.ac.class = &srp_host_class.class;
318 	i->t.host_attrs.ac.match = srp_host_match;
319 	i->host_attrs[0] = NULL;
320 	transport_container_register(&i->t.host_attrs);
321 
322 	i->rport_attr_cont.ac.attrs = &i->rport_attrs[0];
323 	i->rport_attr_cont.ac.class = &srp_rport_class.class;
324 	i->rport_attr_cont.ac.match = srp_rport_match;
325 	transport_container_register(&i->rport_attr_cont);
326 
327 	count = 0;
328 	SETUP_RPORT_ATTRIBUTE_RD(port_id);
329 	SETUP_RPORT_ATTRIBUTE_RD(roles);
330 	i->rport_attrs[count] = NULL;
331 
332 	i->f = ft;
333 
334 	return &i->t;
335 }
336 EXPORT_SYMBOL_GPL(srp_attach_transport);
337 
338 /**
339  * srp_release_transport  -  release SRP transport template instance
340  * @t:		transport template instance
341  */
342 void srp_release_transport(struct scsi_transport_template *t)
343 {
344 	struct srp_internal *i = to_srp_internal(t);
345 
346 	transport_container_unregister(&i->t.host_attrs);
347 	transport_container_unregister(&i->rport_attr_cont);
348 
349 	kfree(i);
350 }
351 EXPORT_SYMBOL_GPL(srp_release_transport);
352 
353 static __init int srp_transport_init(void)
354 {
355 	int ret;
356 
357 	ret = transport_class_register(&srp_host_class);
358 	if (ret)
359 		return ret;
360 	ret = transport_class_register(&srp_rport_class);
361 	if (ret)
362 		goto unregister_host_class;
363 
364 	return 0;
365 unregister_host_class:
366 	transport_class_unregister(&srp_host_class);
367 	return ret;
368 }
369 
370 static void __exit srp_transport_exit(void)
371 {
372 	transport_class_unregister(&srp_host_class);
373 	transport_class_unregister(&srp_rport_class);
374 }
375 
376 MODULE_AUTHOR("FUJITA Tomonori");
377 MODULE_DESCRIPTION("SRP Transport Attributes");
378 MODULE_LICENSE("GPL");
379 
380 module_init(srp_transport_init);
381 module_exit(srp_transport_exit);
382