xref: /freebsd/sys/contrib/openzfs/module/os/linux/spl/spl-kstat.c (revision 071ab5a1f3cbfd29c8fbec27f7e619418adaf074)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  Copyright (C) 2007-2010 Lawrence Livermore National Security, LLC.
4  *  Copyright (C) 2007 The Regents of the University of California.
5  *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
6  *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
7  *  UCRL-CODE-235197
8  *
9  *  This file is part of the SPL, Solaris Porting Layer.
10  *
11  *  The SPL is free software; you can redistribute it and/or modify it
12  *  under the terms of the GNU General Public License as published by the
13  *  Free Software Foundation; either version 2 of the License, or (at your
14  *  option) any later version.
15  *
16  *  The SPL is distributed in the hope that it will be useful, but WITHOUT
17  *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
18  *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
19  *  for more details.
20  *
21  *  You should have received a copy of the GNU General Public License along
22  *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
23  *
24  *  Solaris Porting Layer (SPL) Kstat Implementation.
25  *
26  *  Links to Illumos.org for more information on kstat function:
27  *  [1] https://illumos.org/man/1M/kstat
28  *  [2] https://illumos.org/man/9f/kstat_create
29  */
30 /*
31  * Copyright (c) 2024-2025, Klara, Inc.
32  * Copyright (c) 2024-2025, Syneto
33  */
34 
35 #include <linux/seq_file.h>
36 #include <sys/kstat.h>
37 #include <sys/vmem.h>
38 #include <sys/cmn_err.h>
39 #include <sys/sysmacros.h>
40 #include <sys/string.h>
41 
42 static kmutex_t kstat_module_lock;
43 static struct list_head kstat_module_list;
44 static kid_t kstat_id;
45 
46 static int
kstat_resize_raw(kstat_t * ksp)47 kstat_resize_raw(kstat_t *ksp)
48 {
49 	if (ksp->ks_raw_bufsize == KSTAT_RAW_MAX)
50 		return (ENOMEM);
51 
52 	vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize);
53 	ksp->ks_raw_bufsize = MIN(ksp->ks_raw_bufsize * 2, KSTAT_RAW_MAX);
54 	ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP);
55 
56 	return (0);
57 }
58 
59 static int
kstat_seq_show_headers(struct seq_file * f)60 kstat_seq_show_headers(struct seq_file *f)
61 {
62 	kstat_t *ksp = (kstat_t *)f->private;
63 	int rc = 0;
64 
65 	ASSERT(ksp->ks_magic == KS_MAGIC);
66 
67 	seq_printf(f, "%d %d 0x%02x %d %d %lld %lld\n",
68 	    ksp->ks_kid, ksp->ks_type, ksp->ks_flags,
69 	    ksp->ks_ndata, (int)ksp->ks_data_size,
70 	    ksp->ks_crtime, ksp->ks_snaptime);
71 
72 	switch (ksp->ks_type) {
73 		case KSTAT_TYPE_RAW:
74 restart:
75 			if (ksp->ks_raw_ops.headers) {
76 				rc = ksp->ks_raw_ops.headers(
77 				    ksp->ks_raw_buf, ksp->ks_raw_bufsize);
78 				if (rc == ENOMEM && !kstat_resize_raw(ksp))
79 					goto restart;
80 				if (!rc)
81 					seq_puts(f, ksp->ks_raw_buf);
82 			} else {
83 				seq_printf(f, "raw data\n");
84 			}
85 			break;
86 		case KSTAT_TYPE_NAMED:
87 			seq_printf(f, "%-31s %-4s %s\n",
88 			    "name", "type", "data");
89 			break;
90 		case KSTAT_TYPE_INTR:
91 			seq_printf(f, "%-8s %-8s %-8s %-8s %-8s\n",
92 			    "hard", "soft", "watchdog",
93 			    "spurious", "multsvc");
94 			break;
95 		case KSTAT_TYPE_IO:
96 			seq_printf(f,
97 			    "%-8s %-8s %-8s %-8s %-8s %-8s "
98 			    "%-8s %-8s %-8s %-8s %-8s %-8s\n",
99 			    "nread", "nwritten", "reads", "writes",
100 			    "wtime", "wlentime", "wupdate",
101 			    "rtime", "rlentime", "rupdate",
102 			    "wcnt", "rcnt");
103 			break;
104 		case KSTAT_TYPE_TIMER:
105 			seq_printf(f,
106 			    "%-31s %-8s "
107 			    "%-8s %-8s %-8s %-8s %-8s\n",
108 			    "name", "events", "elapsed",
109 			    "min", "max", "start", "stop");
110 			break;
111 		default:
112 			PANIC("Undefined kstat type %d\n", ksp->ks_type);
113 	}
114 
115 	return (-rc);
116 }
117 
118 static int
kstat_seq_show_raw(struct seq_file * f,unsigned char * p,int l)119 kstat_seq_show_raw(struct seq_file *f, unsigned char *p, int l)
120 {
121 	int i, j;
122 
123 	for (i = 0; ; i++) {
124 		seq_printf(f, "%03x:", i);
125 
126 		for (j = 0; j < 16; j++) {
127 			if (i * 16 + j >= l) {
128 				seq_printf(f, "\n");
129 				goto out;
130 			}
131 
132 			seq_printf(f, " %02x", (unsigned char)p[i * 16 + j]);
133 		}
134 		seq_printf(f, "\n");
135 	}
136 out:
137 	return (0);
138 }
139 
140 static int
kstat_seq_show_named(struct seq_file * f,kstat_named_t * knp)141 kstat_seq_show_named(struct seq_file *f, kstat_named_t *knp)
142 {
143 	seq_printf(f, "%-31s %-4d ", knp->name, knp->data_type);
144 
145 	switch (knp->data_type) {
146 		case KSTAT_DATA_CHAR:
147 			knp->value.c[15] = '\0'; /* NULL terminate */
148 			seq_printf(f, "%-16s", knp->value.c);
149 			break;
150 		/*
151 		 * NOTE - We need to be more careful able what tokens are
152 		 * used for each arch, for now this is correct for x86_64.
153 		 */
154 		case KSTAT_DATA_INT32:
155 			seq_printf(f, "%d", knp->value.i32);
156 			break;
157 		case KSTAT_DATA_UINT32:
158 			seq_printf(f, "%u", knp->value.ui32);
159 			break;
160 		case KSTAT_DATA_INT64:
161 			seq_printf(f, "%lld", (signed long long)knp->value.i64);
162 			break;
163 		case KSTAT_DATA_UINT64:
164 			seq_printf(f, "%llu",
165 			    (unsigned long long)knp->value.ui64);
166 			break;
167 		case KSTAT_DATA_LONG:
168 			seq_printf(f, "%ld", knp->value.l);
169 			break;
170 		case KSTAT_DATA_ULONG:
171 			seq_printf(f, "%lu", knp->value.ul);
172 			break;
173 		case KSTAT_DATA_STRING:
174 			KSTAT_NAMED_STR_PTR(knp)
175 				[KSTAT_NAMED_STR_BUFLEN(knp)-1] = '\0';
176 			seq_printf(f, "%s", KSTAT_NAMED_STR_PTR(knp));
177 			break;
178 		default:
179 			PANIC("Undefined kstat data type %d\n", knp->data_type);
180 	}
181 
182 	seq_printf(f, "\n");
183 
184 	return (0);
185 }
186 
187 static int
kstat_seq_show_intr(struct seq_file * f,kstat_intr_t * kip)188 kstat_seq_show_intr(struct seq_file *f, kstat_intr_t *kip)
189 {
190 	seq_printf(f, "%-8u %-8u %-8u %-8u %-8u\n",
191 	    kip->intrs[KSTAT_INTR_HARD],
192 	    kip->intrs[KSTAT_INTR_SOFT],
193 	    kip->intrs[KSTAT_INTR_WATCHDOG],
194 	    kip->intrs[KSTAT_INTR_SPURIOUS],
195 	    kip->intrs[KSTAT_INTR_MULTSVC]);
196 
197 	return (0);
198 }
199 
200 static int
kstat_seq_show_io(struct seq_file * f,kstat_io_t * kip)201 kstat_seq_show_io(struct seq_file *f, kstat_io_t *kip)
202 {
203 	/* though wlentime & friends are signed, they will never be negative */
204 	seq_printf(f,
205 	    "%-8llu %-8llu %-8u %-8u %-8llu %-8llu "
206 	    "%-8llu %-8llu %-8llu %-8llu %-8u %-8u\n",
207 	    kip->nread, kip->nwritten,
208 	    kip->reads, kip->writes,
209 	    kip->wtime, kip->wlentime, kip->wlastupdate,
210 	    kip->rtime, kip->rlentime, kip->rlastupdate,
211 	    kip->wcnt,  kip->rcnt);
212 
213 	return (0);
214 }
215 
216 static int
kstat_seq_show_timer(struct seq_file * f,kstat_timer_t * ktp)217 kstat_seq_show_timer(struct seq_file *f, kstat_timer_t *ktp)
218 {
219 	seq_printf(f,
220 	    "%-31s %-8llu %-8llu %-8llu %-8llu %-8llu %-8llu\n",
221 	    ktp->name, ktp->num_events, ktp->elapsed_time,
222 	    ktp->min_time, ktp->max_time,
223 	    ktp->start_time, ktp->stop_time);
224 
225 	return (0);
226 }
227 
228 static int
kstat_seq_show(struct seq_file * f,void * p)229 kstat_seq_show(struct seq_file *f, void *p)
230 {
231 	kstat_t *ksp = (kstat_t *)f->private;
232 	int rc = 0;
233 
234 	ASSERT(ksp->ks_magic == KS_MAGIC);
235 
236 	switch (ksp->ks_type) {
237 		case KSTAT_TYPE_RAW:
238 restart:
239 			if (ksp->ks_raw_ops.data) {
240 				rc = ksp->ks_raw_ops.data(
241 				    ksp->ks_raw_buf, ksp->ks_raw_bufsize, p);
242 				if (rc == ENOMEM && !kstat_resize_raw(ksp))
243 					goto restart;
244 				if (!rc)
245 					seq_puts(f, ksp->ks_raw_buf);
246 			} else {
247 				ASSERT(ksp->ks_ndata == 1);
248 				rc = kstat_seq_show_raw(f, ksp->ks_data,
249 				    ksp->ks_data_size);
250 			}
251 			break;
252 		case KSTAT_TYPE_NAMED:
253 			rc = kstat_seq_show_named(f, (kstat_named_t *)p);
254 			break;
255 		case KSTAT_TYPE_INTR:
256 			rc = kstat_seq_show_intr(f, (kstat_intr_t *)p);
257 			break;
258 		case KSTAT_TYPE_IO:
259 			rc = kstat_seq_show_io(f, (kstat_io_t *)p);
260 			break;
261 		case KSTAT_TYPE_TIMER:
262 			rc = kstat_seq_show_timer(f, (kstat_timer_t *)p);
263 			break;
264 		default:
265 			PANIC("Undefined kstat type %d\n", ksp->ks_type);
266 	}
267 
268 	return (-rc);
269 }
270 
271 static int
kstat_default_update(kstat_t * ksp,int rw)272 kstat_default_update(kstat_t *ksp, int rw)
273 {
274 	ASSERT(ksp != NULL);
275 
276 	if (rw == KSTAT_WRITE)
277 		return (EACCES);
278 
279 	return (0);
280 }
281 
282 static void *
kstat_seq_data_addr(kstat_t * ksp,loff_t n)283 kstat_seq_data_addr(kstat_t *ksp, loff_t n)
284 {
285 	void *rc = NULL;
286 
287 	switch (ksp->ks_type) {
288 		case KSTAT_TYPE_RAW:
289 			if (ksp->ks_raw_ops.addr)
290 				rc = ksp->ks_raw_ops.addr(ksp, n);
291 			else
292 				rc = ksp->ks_data;
293 			break;
294 		case KSTAT_TYPE_NAMED:
295 			rc = ksp->ks_data + n * sizeof (kstat_named_t);
296 			break;
297 		case KSTAT_TYPE_INTR:
298 			rc = ksp->ks_data + n * sizeof (kstat_intr_t);
299 			break;
300 		case KSTAT_TYPE_IO:
301 			rc = ksp->ks_data + n * sizeof (kstat_io_t);
302 			break;
303 		case KSTAT_TYPE_TIMER:
304 			rc = ksp->ks_data + n * sizeof (kstat_timer_t);
305 			break;
306 		default:
307 			PANIC("Undefined kstat type %d\n", ksp->ks_type);
308 	}
309 
310 	return (rc);
311 }
312 
313 static void *
kstat_seq_start(struct seq_file * f,loff_t * pos)314 kstat_seq_start(struct seq_file *f, loff_t *pos)
315 {
316 	loff_t n = *pos;
317 	kstat_t *ksp = (kstat_t *)f->private;
318 	ASSERT(ksp->ks_magic == KS_MAGIC);
319 
320 	mutex_enter(ksp->ks_lock);
321 
322 	if (ksp->ks_type == KSTAT_TYPE_RAW) {
323 		ksp->ks_raw_bufsize = PAGE_SIZE;
324 		ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP);
325 	}
326 
327 	/* Dynamically update kstat, on error existing kstats are used */
328 	(void) ksp->ks_update(ksp, KSTAT_READ);
329 
330 	ksp->ks_snaptime = gethrtime();
331 
332 	if (!(ksp->ks_flags & KSTAT_FLAG_NO_HEADERS) && !n &&
333 	    kstat_seq_show_headers(f))
334 		return (NULL);
335 
336 	if (n >= ksp->ks_ndata)
337 		return (NULL);
338 
339 	return (kstat_seq_data_addr(ksp, n));
340 }
341 
342 static void *
kstat_seq_next(struct seq_file * f,void * p,loff_t * pos)343 kstat_seq_next(struct seq_file *f, void *p, loff_t *pos)
344 {
345 	kstat_t *ksp = (kstat_t *)f->private;
346 	ASSERT(ksp->ks_magic == KS_MAGIC);
347 
348 	++*pos;
349 	if (*pos >= ksp->ks_ndata)
350 		return (NULL);
351 
352 	return (kstat_seq_data_addr(ksp, *pos));
353 }
354 
355 static void
kstat_seq_stop(struct seq_file * f,void * v)356 kstat_seq_stop(struct seq_file *f, void *v)
357 {
358 	kstat_t *ksp = (kstat_t *)f->private;
359 	ASSERT(ksp->ks_magic == KS_MAGIC);
360 
361 	if (ksp->ks_type == KSTAT_TYPE_RAW)
362 		vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize);
363 
364 	mutex_exit(ksp->ks_lock);
365 }
366 
367 static const struct seq_operations kstat_seq_ops = {
368 	.show  = kstat_seq_show,
369 	.start = kstat_seq_start,
370 	.next  = kstat_seq_next,
371 	.stop  = kstat_seq_stop,
372 };
373 
374 static kstat_module_t *
kstat_find_module(char * name)375 kstat_find_module(char *name)
376 {
377 	ASSERT(MUTEX_HELD(&kstat_module_lock));
378 
379 	kstat_module_t *module = NULL;
380 
381 	list_for_each_entry(module, &kstat_module_list, ksm_module_list) {
382 		if (strncmp(name, module->ksm_name, KSTAT_STRLEN) == 0)
383 			return (module);
384 	}
385 
386 	return (NULL);
387 }
388 
389 static void
kstat_delete_module(kstat_module_t * module)390 kstat_delete_module(kstat_module_t *module)
391 {
392 	ASSERT(MUTEX_HELD(&kstat_module_lock));
393 	ASSERT(list_empty(&module->ksm_kstat_list));
394 	ASSERT0(module->ksm_nchildren);
395 
396 	kstat_module_t *parent = module->ksm_parent;
397 
398 	char *p = module->ksm_name, *frag = NULL;
399 	while (p != NULL && (frag = strsep(&p, "/"))) {}
400 
401 	remove_proc_entry(frag, parent ? parent->ksm_proc : proc_spl_kstat);
402 	list_del(&module->ksm_module_list);
403 	kmem_free(module, sizeof (kstat_module_t));
404 
405 	if (parent) {
406 		parent->ksm_nchildren--;
407 		if (parent->ksm_nchildren == 0 &&
408 		    list_empty(&parent->ksm_kstat_list))
409 			kstat_delete_module(parent);
410 	}
411 }
412 
413 static kstat_module_t *
kstat_create_module(char * name)414 kstat_create_module(char *name)
415 {
416 	ASSERT(MUTEX_HELD(&kstat_module_lock));
417 
418 	char buf[KSTAT_STRLEN];
419 	kstat_module_t *module, *parent;
420 
421 	(void) strlcpy(buf, name, KSTAT_STRLEN);
422 
423 	module = parent = NULL;
424 	char *p = buf, *frag;
425 	while ((frag = strsep(&p, "/")) != NULL) {
426 		module = kstat_find_module(buf);
427 		if (module == NULL) {
428 			struct proc_dir_entry *pde = proc_mkdir(frag,
429 			    parent ? parent->ksm_proc : proc_spl_kstat);
430 			if (pde == NULL) {
431 				cmn_err(CE_WARN, "kstat_create('%s'): "
432 				    "module dir create failed", buf);
433 				if (parent)
434 					kstat_delete_module(parent);
435 				return (NULL);
436 			}
437 
438 			module = kmem_zalloc(sizeof (kstat_module_t), KM_SLEEP);
439 			module->ksm_proc = pde;
440 			strlcpy(module->ksm_name, buf, KSTAT_STRLEN);
441 			INIT_LIST_HEAD(&module->ksm_kstat_list);
442 			list_add_tail(&module->ksm_module_list,
443 			    &kstat_module_list);
444 
445 			if (parent != NULL) {
446 				module->ksm_parent = parent;
447 				parent->ksm_nchildren++;
448 			}
449 		}
450 
451 		parent = module;
452 		if (p != NULL)
453 			p[-1] = '/';
454 	}
455 
456 	return (module);
457 }
458 
459 static int
proc_kstat_open(struct inode * inode,struct file * filp)460 proc_kstat_open(struct inode *inode, struct file *filp)
461 {
462 	struct seq_file *f;
463 	int rc;
464 
465 	rc = seq_open(filp, &kstat_seq_ops);
466 	if (rc)
467 		return (rc);
468 
469 	f = filp->private_data;
470 	f->private = SPL_PDE_DATA(inode);
471 
472 	return (0);
473 }
474 
475 static ssize_t
proc_kstat_write(struct file * filp,const char __user * buf,size_t len,loff_t * ppos)476 proc_kstat_write(struct file *filp, const char __user *buf, size_t len,
477     loff_t *ppos)
478 {
479 	struct seq_file *f = filp->private_data;
480 	kstat_t *ksp = f->private;
481 	int rc;
482 
483 	ASSERT(ksp->ks_magic == KS_MAGIC);
484 
485 	mutex_enter(ksp->ks_lock);
486 	rc = ksp->ks_update(ksp, KSTAT_WRITE);
487 	mutex_exit(ksp->ks_lock);
488 
489 	if (rc)
490 		return (-rc);
491 
492 	*ppos += len;
493 	return (len);
494 }
495 
496 static const kstat_proc_op_t proc_kstat_operations = {
497 #ifdef HAVE_PROC_OPS_STRUCT
498 	.proc_open	= proc_kstat_open,
499 	.proc_write	= proc_kstat_write,
500 	.proc_read	= seq_read,
501 	.proc_lseek	= seq_lseek,
502 	.proc_release	= seq_release,
503 #else
504 	.open		= proc_kstat_open,
505 	.write		= proc_kstat_write,
506 	.read		= seq_read,
507 	.llseek		= seq_lseek,
508 	.release	= seq_release,
509 #endif
510 };
511 
512 void
__kstat_set_raw_ops(kstat_t * ksp,int (* headers)(char * buf,size_t size),int (* data)(char * buf,size_t size,void * data),void * (* addr)(kstat_t * ksp,loff_t index))513 __kstat_set_raw_ops(kstat_t *ksp,
514     int (*headers)(char *buf, size_t size),
515     int (*data)(char *buf, size_t size, void *data),
516     void *(*addr)(kstat_t *ksp, loff_t index))
517 {
518 	ksp->ks_raw_ops.headers = headers;
519 	ksp->ks_raw_ops.data    = data;
520 	ksp->ks_raw_ops.addr    = addr;
521 }
522 EXPORT_SYMBOL(__kstat_set_raw_ops);
523 
524 void
kstat_proc_entry_init(kstat_proc_entry_t * kpep,const char * module,const char * name)525 kstat_proc_entry_init(kstat_proc_entry_t *kpep, const char *module,
526     const char *name)
527 {
528 	kpep->kpe_owner = NULL;
529 	kpep->kpe_proc = NULL;
530 	INIT_LIST_HEAD(&kpep->kpe_list);
531 	strlcpy(kpep->kpe_module, module, sizeof (kpep->kpe_module));
532 	strlcpy(kpep->kpe_name, name, sizeof (kpep->kpe_name));
533 }
534 EXPORT_SYMBOL(kstat_proc_entry_init);
535 
536 kstat_t *
__kstat_create(const char * ks_module,int ks_instance,const char * ks_name,const char * ks_class,uchar_t ks_type,uint_t ks_ndata,uchar_t ks_flags)537 __kstat_create(const char *ks_module, int ks_instance, const char *ks_name,
538     const char *ks_class, uchar_t ks_type, uint_t ks_ndata,
539     uchar_t ks_flags)
540 {
541 	kstat_t *ksp;
542 
543 	ASSERT(ks_module);
544 	ASSERT(ks_instance == 0);
545 	ASSERT(ks_name);
546 
547 	if ((ks_type == KSTAT_TYPE_INTR) || (ks_type == KSTAT_TYPE_IO))
548 		ASSERT(ks_ndata == 1);
549 
550 	ksp = kmem_zalloc(sizeof (*ksp), KM_SLEEP);
551 	if (ksp == NULL)
552 		return (ksp);
553 
554 	mutex_enter(&kstat_module_lock);
555 	ksp->ks_kid = kstat_id;
556 	kstat_id++;
557 	mutex_exit(&kstat_module_lock);
558 
559 	ksp->ks_magic = KS_MAGIC;
560 	mutex_init(&ksp->ks_private_lock, NULL, MUTEX_DEFAULT, NULL);
561 	ksp->ks_lock = &ksp->ks_private_lock;
562 
563 	ksp->ks_crtime = gethrtime();
564 	ksp->ks_snaptime = ksp->ks_crtime;
565 	ksp->ks_instance = ks_instance;
566 	strlcpy(ksp->ks_class, ks_class, sizeof (ksp->ks_class));
567 	ksp->ks_type = ks_type;
568 	ksp->ks_flags = ks_flags;
569 	ksp->ks_update = kstat_default_update;
570 	ksp->ks_private = NULL;
571 	ksp->ks_raw_ops.headers = NULL;
572 	ksp->ks_raw_ops.data = NULL;
573 	ksp->ks_raw_ops.addr = NULL;
574 	ksp->ks_raw_buf = NULL;
575 	ksp->ks_raw_bufsize = 0;
576 	kstat_proc_entry_init(&ksp->ks_proc, ks_module, ks_name);
577 
578 	switch (ksp->ks_type) {
579 		case KSTAT_TYPE_RAW:
580 			ksp->ks_ndata = 1;
581 			ksp->ks_data_size = ks_ndata;
582 			break;
583 		case KSTAT_TYPE_NAMED:
584 			ksp->ks_ndata = ks_ndata;
585 			ksp->ks_data_size = ks_ndata * sizeof (kstat_named_t);
586 			break;
587 		case KSTAT_TYPE_INTR:
588 			ksp->ks_ndata = ks_ndata;
589 			ksp->ks_data_size = ks_ndata * sizeof (kstat_intr_t);
590 			break;
591 		case KSTAT_TYPE_IO:
592 			ksp->ks_ndata = ks_ndata;
593 			ksp->ks_data_size = ks_ndata * sizeof (kstat_io_t);
594 			break;
595 		case KSTAT_TYPE_TIMER:
596 			ksp->ks_ndata = ks_ndata;
597 			ksp->ks_data_size = ks_ndata * sizeof (kstat_timer_t);
598 			break;
599 		default:
600 			PANIC("Undefined kstat type %d\n", ksp->ks_type);
601 	}
602 
603 	if (ksp->ks_flags & KSTAT_FLAG_VIRTUAL) {
604 		ksp->ks_data = NULL;
605 	} else {
606 		ksp->ks_data = kmem_zalloc(ksp->ks_data_size, KM_SLEEP);
607 		if (ksp->ks_data == NULL) {
608 			kmem_free(ksp, sizeof (*ksp));
609 			ksp = NULL;
610 		}
611 	}
612 
613 	return (ksp);
614 }
615 EXPORT_SYMBOL(__kstat_create);
616 
617 static int
kstat_detect_collision(kstat_proc_entry_t * kpep)618 kstat_detect_collision(kstat_proc_entry_t *kpep)
619 {
620 	kstat_module_t *module;
621 	kstat_proc_entry_t *tmp = NULL;
622 	char *parent;
623 	char *cp;
624 
625 	parent = kmem_asprintf("%s", kpep->kpe_module);
626 
627 	if ((cp = strrchr(parent, '/')) == NULL) {
628 		kmem_strfree(parent);
629 		return (0);
630 	}
631 
632 	cp[0] = '\0';
633 	if ((module = kstat_find_module(parent)) != NULL) {
634 		list_for_each_entry(tmp, &module->ksm_kstat_list, kpe_list) {
635 			if (strncmp(tmp->kpe_name, cp+1, KSTAT_STRLEN) == 0) {
636 				kmem_strfree(parent);
637 				return (EEXIST);
638 			}
639 		}
640 	}
641 
642 	kmem_strfree(parent);
643 	return (0);
644 }
645 
646 /*
647  * Add a file to the proc filesystem under the kstat namespace (i.e.
648  * /proc/spl/kstat/). The file need not necessarily be implemented as a
649  * kstat.
650  */
651 void
kstat_proc_entry_install(kstat_proc_entry_t * kpep,mode_t mode,const kstat_proc_op_t * proc_ops,void * data)652 kstat_proc_entry_install(kstat_proc_entry_t *kpep, mode_t mode,
653     const kstat_proc_op_t *proc_ops, void *data)
654 {
655 	kstat_module_t *module;
656 	kstat_proc_entry_t *tmp = NULL;
657 
658 	ASSERT(kpep);
659 
660 	mutex_enter(&kstat_module_lock);
661 
662 	module = kstat_find_module(kpep->kpe_module);
663 	if (module == NULL) {
664 		if (kstat_detect_collision(kpep) != 0) {
665 			cmn_err(CE_WARN, "kstat_create('%s', '%s'): namespace" \
666 			    " collision", kpep->kpe_module, kpep->kpe_name);
667 			goto out;
668 		}
669 		module = kstat_create_module(kpep->kpe_module);
670 		if (module == NULL)
671 			goto out;
672 	}
673 
674 	/*
675 	 * We can only have one entry of this name per module. If one already
676 	 * exists, replace it by first removing the proc entry, then removing
677 	 * it from the list. The kstat itself lives on; it just can't be
678 	 * inspected through the filesystem.
679 	 */
680 	list_for_each_entry(tmp, &module->ksm_kstat_list, kpe_list) {
681 		if (tmp->kpe_proc != NULL &&
682 		    strncmp(tmp->kpe_name, kpep->kpe_name, KSTAT_STRLEN) == 0) {
683 			ASSERT3P(tmp->kpe_owner, ==, module);
684 			remove_proc_entry(tmp->kpe_name, module->ksm_proc);
685 			tmp->kpe_proc = NULL;
686 			list_del_init(&tmp->kpe_list);
687 			break;
688 		}
689 	}
690 
691 	list_add_tail(&kpep->kpe_list, &module->ksm_kstat_list);
692 
693 	kpep->kpe_owner = module;
694 	kpep->kpe_proc = proc_create_data(kpep->kpe_name, mode,
695 	    module->ksm_proc, proc_ops, data);
696 	if (kpep->kpe_proc == NULL) {
697 		list_del_init(&kpep->kpe_list);
698 		if (list_empty(&module->ksm_kstat_list))
699 			kstat_delete_module(module);
700 	}
701 out:
702 	mutex_exit(&kstat_module_lock);
703 
704 }
705 EXPORT_SYMBOL(kstat_proc_entry_install);
706 
707 void
__kstat_install(kstat_t * ksp)708 __kstat_install(kstat_t *ksp)
709 {
710 	ASSERT(ksp);
711 	mode_t mode;
712 	/* Specify permission modes for different kstats */
713 	if (strncmp(ksp->ks_proc.kpe_name, "dbufs", KSTAT_STRLEN) == 0) {
714 		mode = 0600;
715 	} else {
716 		mode = 0644;
717 	}
718 	kstat_proc_entry_install(
719 	    &ksp->ks_proc, mode, &proc_kstat_operations, ksp);
720 }
721 EXPORT_SYMBOL(__kstat_install);
722 
723 void
kstat_proc_entry_delete(kstat_proc_entry_t * kpep)724 kstat_proc_entry_delete(kstat_proc_entry_t *kpep)
725 {
726 	kstat_module_t *module = kpep->kpe_owner;
727 	if (kpep->kpe_proc)
728 		remove_proc_entry(kpep->kpe_name, module->ksm_proc);
729 
730 	mutex_enter(&kstat_module_lock);
731 	list_del_init(&kpep->kpe_list);
732 
733 	/*
734 	 * Remove top level module directory if it wasn't empty before, but now
735 	 * is.
736 	 */
737 	if (kpep->kpe_proc && list_empty(&module->ksm_kstat_list))
738 		kstat_delete_module(module);
739 	mutex_exit(&kstat_module_lock);
740 
741 }
742 EXPORT_SYMBOL(kstat_proc_entry_delete);
743 
744 void
__kstat_delete(kstat_t * ksp)745 __kstat_delete(kstat_t *ksp)
746 {
747 	kstat_proc_entry_delete(&ksp->ks_proc);
748 
749 	if (!(ksp->ks_flags & KSTAT_FLAG_VIRTUAL))
750 		kmem_free(ksp->ks_data, ksp->ks_data_size);
751 
752 	ksp->ks_lock = NULL;
753 	mutex_destroy(&ksp->ks_private_lock);
754 	kmem_free(ksp, sizeof (*ksp));
755 }
756 EXPORT_SYMBOL(__kstat_delete);
757 
758 int
spl_kstat_init(void)759 spl_kstat_init(void)
760 {
761 	mutex_init(&kstat_module_lock, NULL, MUTEX_DEFAULT, NULL);
762 	INIT_LIST_HEAD(&kstat_module_list);
763 	kstat_id = 0;
764 	return (0);
765 }
766 
767 void
spl_kstat_fini(void)768 spl_kstat_fini(void)
769 {
770 	ASSERT(list_empty(&kstat_module_list));
771 	mutex_destroy(&kstat_module_lock);
772 }
773