xref: /linux/drivers/block/aoe/aoedev.c (revision c532de5a67a70f8533d495f8f2aaa9a0491c3ad0) 
1 /* Copyright (c) 2013 Coraid, Inc.  See COPYING for GPL terms. */
2 /*
3  * aoedev.c
4  * AoE device utility functions; maintains device list.
5  */
6 
7 #include <linux/hdreg.h>
8 #include <linux/blk-mq.h>
9 #include <linux/netdevice.h>
10 #include <linux/delay.h>
11 #include <linux/slab.h>
12 #include <linux/bitmap.h>
13 #include <linux/kdev_t.h>
14 #include <linux/moduleparam.h>
15 #include <linux/string.h>
16 #include "aoe.h"
17 
18 static void freetgt(struct aoedev *d, struct aoetgt *t);
19 static void skbpoolfree(struct aoedev *d);
20 
21 static int aoe_dyndevs = 1;
22 module_param(aoe_dyndevs, int, 0644);
23 MODULE_PARM_DESC(aoe_dyndevs, "Use dynamic minor numbers for devices.");
24 
25 static struct aoedev *devlist;
26 static DEFINE_SPINLOCK(devlist_lock);
27 
28 /* Because some systems will have one, many, or no
29  *   - partitions,
30  *   - slots per shelf,
31  *   - or shelves,
32  * we need some flexibility in the way the minor numbers
33  * are allocated.  So they are dynamic.
34  */
35 #define N_DEVS ((1U<<MINORBITS)/AOE_PARTITIONS)
36 
37 static DEFINE_SPINLOCK(used_minors_lock);
38 static DECLARE_BITMAP(used_minors, N_DEVS);
39 
40 static int
41 minor_get_dyn(ulong *sysminor)
42 {
43 	ulong flags;
44 	ulong n;
45 	int error = 0;
46 
47 	spin_lock_irqsave(&used_minors_lock, flags);
48 	n = find_first_zero_bit(used_minors, N_DEVS);
49 	if (n < N_DEVS)
50 		set_bit(n, used_minors);
51 	else
52 		error = -1;
53 	spin_unlock_irqrestore(&used_minors_lock, flags);
54 
55 	*sysminor = n * AOE_PARTITIONS;
56 	return error;
57 }
58 
59 static int
60 minor_get_static(ulong *sysminor, ulong aoemaj, int aoemin)
61 {
62 	ulong flags;
63 	ulong n;
64 	int error = 0;
65 	enum {
66 		/* for backwards compatibility when !aoe_dyndevs,
67 		 * a static number of supported slots per shelf */
68 		NPERSHELF = 16,
69 	};
70 
71 	if (aoemin >= NPERSHELF) {
72 		pr_err("aoe: %s %d slots per shelf\n",
73 			"static minor device numbers support only",
74 			NPERSHELF);
75 		error = -1;
76 		goto out;
77 	}
78 
79 	n = aoemaj * NPERSHELF + aoemin;
80 	if (n >= N_DEVS) {
81 		pr_err("aoe: %s with e%ld.%d\n",
82 			"cannot use static minor device numbers",
83 			aoemaj, aoemin);
84 		error = -1;
85 		goto out;
86 	}
87 
88 	spin_lock_irqsave(&used_minors_lock, flags);
89 	if (test_bit(n, used_minors)) {
90 		pr_err("aoe: %s %lu\n",
91 			"existing device already has static minor number",
92 			n);
93 		error = -1;
94 	} else
95 		set_bit(n, used_minors);
96 	spin_unlock_irqrestore(&used_minors_lock, flags);
97 	*sysminor = n * AOE_PARTITIONS;
98 out:
99 	return error;
100 }
101 
102 static int
103 minor_get(ulong *sysminor, ulong aoemaj, int aoemin)
104 {
105 	if (aoe_dyndevs)
106 		return minor_get_dyn(sysminor);
107 	else
108 		return minor_get_static(sysminor, aoemaj, aoemin);
109 }
110 
111 static void
112 minor_free(ulong minor)
113 {
114 	ulong flags;
115 
116 	minor /= AOE_PARTITIONS;
117 	BUG_ON(minor >= N_DEVS);
118 
119 	spin_lock_irqsave(&used_minors_lock, flags);
120 	BUG_ON(!test_bit(minor, used_minors));
121 	clear_bit(minor, used_minors);
122 	spin_unlock_irqrestore(&used_minors_lock, flags);
123 }
124 
125 /*
126  * Users who grab a pointer to the device with aoedev_by_aoeaddr
127  * automatically get a reference count and must be responsible
128  * for performing a aoedev_put.  With the addition of async
129  * kthread processing I'm no longer confident that we can
130  * guarantee consistency in the face of device flushes.
131  *
132  * For the time being, we only bother to add extra references for
133  * frames sitting on the iocq.  When the kthreads finish processing
134  * these frames, they will aoedev_put the device.
135  */
136 
137 void
138 aoedev_put(struct aoedev *d)
139 {
140 	ulong flags;
141 
142 	spin_lock_irqsave(&devlist_lock, flags);
143 	d->ref--;
144 	spin_unlock_irqrestore(&devlist_lock, flags);
145 }
146 
147 static void
148 dummy_timer(struct timer_list *t)
149 {
150 	struct aoedev *d;
151 
152 	d = from_timer(d, t, timer);
153 	if (d->flags & DEVFL_TKILL)
154 		return;
155 	d->timer.expires = jiffies + HZ;
156 	add_timer(&d->timer);
157 }
158 
159 static void
160 aoe_failip(struct aoedev *d)
161 {
162 	struct request *rq;
163 	struct aoe_req *req;
164 	struct bio *bio;
165 
166 	aoe_failbuf(d, d->ip.buf);
167 	rq = d->ip.rq;
168 	if (rq == NULL)
169 		return;
170 
171 	req = blk_mq_rq_to_pdu(rq);
172 	while ((bio = d->ip.nxbio)) {
173 		bio->bi_status = BLK_STS_IOERR;
174 		d->ip.nxbio = bio->bi_next;
175 		req->nr_bios--;
176 	}
177 
178 	if (!req->nr_bios)
179 		aoe_end_request(d, rq, 0);
180 }
181 
182 static void
183 downdev_frame(struct list_head *pos)
184 {
185 	struct frame *f;
186 
187 	f = list_entry(pos, struct frame, head);
188 	list_del(pos);
189 	if (f->buf) {
190 		f->buf->nframesout--;
191 		aoe_failbuf(f->t->d, f->buf);
192 	}
193 	aoe_freetframe(f);
194 }
195 
196 void
197 aoedev_downdev(struct aoedev *d)
198 {
199 	struct aoetgt *t, **tt, **te;
200 	struct list_head *head, *pos, *nx;
201 	int i;
202 
203 	d->flags &= ~DEVFL_UP;
204 
205 	/* clean out active and to-be-retransmitted buffers */
206 	for (i = 0; i < NFACTIVE; i++) {
207 		head = &d->factive[i];
208 		list_for_each_safe(pos, nx, head)
209 			downdev_frame(pos);
210 	}
211 	head = &d->rexmitq;
212 	list_for_each_safe(pos, nx, head)
213 		downdev_frame(pos);
214 
215 	/* reset window dressings */
216 	tt = d->targets;
217 	te = tt + d->ntargets;
218 	for (; tt < te && (t = *tt); tt++) {
219 		aoecmd_wreset(t);
220 		t->nout = 0;
221 	}
222 
223 	/* clean out the in-process request (if any) */
224 	aoe_failip(d);
225 
226 	/* fast fail all pending I/O */
227 	if (d->blkq) {
228 		/* UP is cleared, freeze+quiesce to insure all are errored */
229 		blk_mq_freeze_queue(d->blkq);
230 		blk_mq_quiesce_queue(d->blkq);
231 		blk_mq_unquiesce_queue(d->blkq);
232 		blk_mq_unfreeze_queue(d->blkq);
233 	}
234 
235 	if (d->gd)
236 		set_capacity(d->gd, 0);
237 }
238 
239 /* return whether the user asked for this particular
240  * device to be flushed
241  */
242 static int
243 user_req(char *s, size_t slen, struct aoedev *d)
244 {
245 	const char *p;
246 	size_t lim;
247 
248 	if (!d->gd)
249 		return 0;
250 	p = kbasename(d->gd->disk_name);
251 	lim = sizeof(d->gd->disk_name);
252 	lim -= p - d->gd->disk_name;
253 	if (slen < lim)
254 		lim = slen;
255 
256 	return !strncmp(s, p, lim);
257 }
258 
259 static void
260 freedev(struct aoedev *d)
261 {
262 	struct aoetgt **t, **e;
263 	int freeing = 0;
264 	unsigned long flags;
265 
266 	spin_lock_irqsave(&d->lock, flags);
267 	if (d->flags & DEVFL_TKILL
268 	&& !(d->flags & DEVFL_FREEING)) {
269 		d->flags |= DEVFL_FREEING;
270 		freeing = 1;
271 	}
272 	spin_unlock_irqrestore(&d->lock, flags);
273 	if (!freeing)
274 		return;
275 
276 	del_timer_sync(&d->timer);
277 	if (d->gd) {
278 		aoedisk_rm_debugfs(d);
279 		del_gendisk(d->gd);
280 		put_disk(d->gd);
281 		blk_mq_free_tag_set(&d->tag_set);
282 	}
283 	t = d->targets;
284 	e = t + d->ntargets;
285 	for (; t < e && *t; t++)
286 		freetgt(d, *t);
287 
288 	mempool_destroy(d->bufpool);
289 	skbpoolfree(d);
290 	minor_free(d->sysminor);
291 
292 	spin_lock_irqsave(&d->lock, flags);
293 	d->flags |= DEVFL_FREED;
294 	spin_unlock_irqrestore(&d->lock, flags);
295 }
296 
297 enum flush_parms {
298 	NOT_EXITING = 0,
299 	EXITING = 1,
300 };
301 
302 static int
303 flush(const char __user *str, size_t cnt, int exiting)
304 {
305 	ulong flags;
306 	struct aoedev *d, **dd;
307 	char buf[16];
308 	int all = 0;
309 	int specified = 0;	/* flush a specific device */
310 	unsigned int skipflags;
311 
312 	skipflags = DEVFL_GDALLOC | DEVFL_NEWSIZE | DEVFL_TKILL;
313 
314 	if (!exiting && cnt >= 3) {
315 		if (cnt > sizeof buf)
316 			cnt = sizeof buf;
317 		if (copy_from_user(buf, str, cnt))
318 			return -EFAULT;
319 		all = !strncmp(buf, "all", 3);
320 		if (!all)
321 			specified = 1;
322 	}
323 
324 	flush_workqueue(aoe_wq);
325 	/* pass one: do aoedev_downdev, which might sleep */
326 restart1:
327 	spin_lock_irqsave(&devlist_lock, flags);
328 	for (d = devlist; d; d = d->next) {
329 		spin_lock(&d->lock);
330 		if (d->flags & DEVFL_TKILL)
331 			goto cont;
332 
333 		if (exiting) {
334 			/* unconditionally take each device down */
335 		} else if (specified) {
336 			if (!user_req(buf, cnt, d))
337 				goto cont;
338 		} else if ((!all && (d->flags & DEVFL_UP))
339 		|| d->flags & skipflags
340 		|| d->nopen
341 		|| d->ref)
342 			goto cont;
343 
344 		spin_unlock(&d->lock);
345 		spin_unlock_irqrestore(&devlist_lock, flags);
346 		aoedev_downdev(d);
347 		d->flags |= DEVFL_TKILL;
348 		goto restart1;
349 cont:
350 		spin_unlock(&d->lock);
351 	}
352 	spin_unlock_irqrestore(&devlist_lock, flags);
353 
354 	/* pass two: call freedev, which might sleep,
355 	 * for aoedevs marked with DEVFL_TKILL
356 	 */
357 restart2:
358 	spin_lock_irqsave(&devlist_lock, flags);
359 	for (d = devlist; d; d = d->next) {
360 		spin_lock(&d->lock);
361 		if (d->flags & DEVFL_TKILL
362 		&& !(d->flags & DEVFL_FREEING)) {
363 			spin_unlock(&d->lock);
364 			spin_unlock_irqrestore(&devlist_lock, flags);
365 			freedev(d);
366 			goto restart2;
367 		}
368 		spin_unlock(&d->lock);
369 	}
370 
371 	/* pass three: remove aoedevs marked with DEVFL_FREED */
372 	for (dd = &devlist, d = *dd; d; d = *dd) {
373 		struct aoedev *doomed = NULL;
374 
375 		spin_lock(&d->lock);
376 		if (d->flags & DEVFL_FREED) {
377 			*dd = d->next;
378 			doomed = d;
379 		} else {
380 			dd = &d->next;
381 		}
382 		spin_unlock(&d->lock);
383 		if (doomed)
384 			kfree(doomed->targets);
385 		kfree(doomed);
386 	}
387 	spin_unlock_irqrestore(&devlist_lock, flags);
388 
389 	return 0;
390 }
391 
392 int
393 aoedev_flush(const char __user *str, size_t cnt)
394 {
395 	return flush(str, cnt, NOT_EXITING);
396 }
397 
398 /* This has been confirmed to occur once with Tms=3*1000 due to the
399  * driver changing link and not processing its transmit ring.  The
400  * problem is hard enough to solve by returning an error that I'm
401  * still punting on "solving" this.
402  */
403 static void
404 skbfree(struct sk_buff *skb)
405 {
406 	enum { Sms = 250, Tms = 30 * 1000};
407 	int i = Tms / Sms;
408 
409 	if (skb == NULL)
410 		return;
411 	while (atomic_read(&skb_shinfo(skb)->dataref) != 1 && i-- > 0)
412 		msleep(Sms);
413 	if (i < 0) {
414 		printk(KERN_ERR
415 			"aoe: %s holds ref: %s\n",
416 			skb->dev ? skb->dev->name : "netif",
417 			"cannot free skb -- memory leaked.");
418 		return;
419 	}
420 	skb->truesize -= skb->data_len;
421 	skb_shinfo(skb)->nr_frags = skb->data_len = 0;
422 	skb_trim(skb, 0);
423 	dev_kfree_skb(skb);
424 }
425 
426 static void
427 skbpoolfree(struct aoedev *d)
428 {
429 	struct sk_buff *skb, *tmp;
430 
431 	skb_queue_walk_safe(&d->skbpool, skb, tmp)
432 		skbfree(skb);
433 
434 	__skb_queue_head_init(&d->skbpool);
435 }
436 
437 /* find it or allocate it */
438 struct aoedev *
439 aoedev_by_aoeaddr(ulong maj, int min, int do_alloc)
440 {
441 	struct aoedev *d;
442 	int i;
443 	ulong flags;
444 	ulong sysminor = 0;
445 
446 	spin_lock_irqsave(&devlist_lock, flags);
447 
448 	for (d=devlist; d; d=d->next)
449 		if (d->aoemajor == maj && d->aoeminor == min) {
450 			spin_lock(&d->lock);
451 			if (d->flags & DEVFL_TKILL) {
452 				spin_unlock(&d->lock);
453 				d = NULL;
454 				goto out;
455 			}
456 			d->ref++;
457 			spin_unlock(&d->lock);
458 			break;
459 		}
460 	if (d || !do_alloc || minor_get(&sysminor, maj, min) < 0)
461 		goto out;
462 	d = kcalloc(1, sizeof *d, GFP_ATOMIC);
463 	if (!d)
464 		goto out;
465 	d->targets = kcalloc(NTARGETS, sizeof(*d->targets), GFP_ATOMIC);
466 	if (!d->targets) {
467 		kfree(d);
468 		d = NULL;
469 		goto out;
470 	}
471 	d->ntargets = NTARGETS;
472 	INIT_WORK(&d->work, aoecmd_sleepwork);
473 	spin_lock_init(&d->lock);
474 	INIT_LIST_HEAD(&d->rq_list);
475 	skb_queue_head_init(&d->skbpool);
476 	timer_setup(&d->timer, dummy_timer, 0);
477 	d->timer.expires = jiffies + HZ;
478 	add_timer(&d->timer);
479 	d->bufpool = NULL;	/* defer to aoeblk_gdalloc */
480 	d->tgt = d->targets;
481 	d->ref = 1;
482 	for (i = 0; i < NFACTIVE; i++)
483 		INIT_LIST_HEAD(&d->factive[i]);
484 	INIT_LIST_HEAD(&d->rexmitq);
485 	d->sysminor = sysminor;
486 	d->aoemajor = maj;
487 	d->aoeminor = min;
488 	d->rttavg = RTTAVG_INIT;
489 	d->rttdev = RTTDEV_INIT;
490 	d->next = devlist;
491 	devlist = d;
492  out:
493 	spin_unlock_irqrestore(&devlist_lock, flags);
494 	return d;
495 }
496 
497 static void
498 freetgt(struct aoedev *d, struct aoetgt *t)
499 {
500 	struct frame *f;
501 	struct list_head *pos, *nx, *head;
502 	struct aoeif *ifp;
503 
504 	for (ifp = t->ifs; ifp < &t->ifs[NAOEIFS]; ++ifp) {
505 		if (!ifp->nd)
506 			break;
507 		dev_put(ifp->nd);
508 	}
509 
510 	head = &t->ffree;
511 	list_for_each_safe(pos, nx, head) {
512 		list_del(pos);
513 		f = list_entry(pos, struct frame, head);
514 		skbfree(f->skb);
515 		kfree(f);
516 	}
517 	kfree(t);
518 }
519 
520 void
521 aoedev_exit(void)
522 {
523 	flush_workqueue(aoe_wq);
524 	flush(NULL, 0, EXITING);
525 }
526 
527 int __init
528 aoedev_init(void)
529 {
530 	return 0;
531 }
532