1/*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2007 Pawel Jakub Dawidek <pjd@FreeBSD.org>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD$");
31
32#include <sys/param.h>
33#include <sys/kernel.h>
34#include <sys/systm.h>
35#include <sys/sysctl.h>
36#include <sys/errno.h>
37#include <sys/jail.h>
38#include <sys/malloc.h>
39#include <sys/lock.h>
40#include <sys/mutex.h>
41#include <sys/rmlock.h>
42#include <sys/sx.h>
43#include <sys/queue.h>
44#include <sys/proc.h>
45#include <sys/osd.h>
46
47/* OSD (Object Specific Data) */
48
49/*
50 * Lock key:
51 *  (m) osd_module_lock
52 *  (o) osd_object_lock
53 *  (l) osd_list_lock
54 */
55struct osd_master {
56	struct sx		 osd_module_lock;
57	struct rmlock		 osd_object_lock;
58	struct mtx		 osd_list_lock;
59	LIST_HEAD(, osd)	 osd_list;		/* (l) */
60	osd_destructor_t	*osd_destructors;	/* (o) */
61	osd_method_t		*osd_methods;		/* (m) */
62	u_int			 osd_ntslots;		/* (m) */
63	const u_int		 osd_nmethods;
64};
65
66static MALLOC_DEFINE(M_OSD, "osd", "Object Specific Data");
67
68static int osd_debug = 0;
69SYSCTL_INT(_debug, OID_AUTO, osd, CTLFLAG_RWTUN, &osd_debug, 0, "OSD debug level");
70
71#define	OSD_DEBUG(...)	do {						\
72	if (osd_debug) {						\
73		printf("OSD (%s:%u): ", __func__, __LINE__);		\
74		printf(__VA_ARGS__);					\
75		printf("\n");						\
76	}								\
77} while (0)
78
79static void do_osd_del(u_int type, struct osd *osd, u_int slot,
80    int list_locked);
81
82/*
83 * List of objects with OSD.
84 */
85struct osd_master osdm[OSD_LAST + 1] = {
86	[OSD_JAIL] = { .osd_nmethods = PR_MAXMETHOD },
87};
88
89static void
90osd_default_destructor(void *value __unused)
91{
92	/* Do nothing. */
93}
94
95int
96osd_register(u_int type, osd_destructor_t destructor, osd_method_t *methods)
97{
98	void *newptr;
99	u_int i, m;
100
101	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
102
103	/*
104	 * If no destructor is given, use default one. We need to use some
105	 * destructor, because NULL destructor means unused slot.
106	 */
107	if (destructor == NULL)
108		destructor = osd_default_destructor;
109
110	sx_xlock(&osdm[type].osd_module_lock);
111	/*
112	 * First, we try to find unused slot.
113	 */
114	for (i = 0; i < osdm[type].osd_ntslots; i++) {
115		if (osdm[type].osd_destructors[i] == NULL) {
116			OSD_DEBUG("Unused slot found (type=%u, slot=%u).",
117			    type, i);
118			break;
119		}
120	}
121	/*
122	 * If no unused slot was found, allocate one.
123	 */
124	if (i == osdm[type].osd_ntslots) {
125		osdm[type].osd_ntslots++;
126		if (osdm[type].osd_nmethods != 0)
127			osdm[type].osd_methods = realloc(osdm[type].osd_methods,
128			    sizeof(osd_method_t) * osdm[type].osd_ntslots *
129			    osdm[type].osd_nmethods, M_OSD, M_WAITOK);
130		newptr = malloc(sizeof(osd_destructor_t) *
131		    osdm[type].osd_ntslots, M_OSD, M_WAITOK);
132		rm_wlock(&osdm[type].osd_object_lock);
133		bcopy(osdm[type].osd_destructors, newptr,
134		    sizeof(osd_destructor_t) * i);
135		free(osdm[type].osd_destructors, M_OSD);
136		osdm[type].osd_destructors = newptr;
137		rm_wunlock(&osdm[type].osd_object_lock);
138		OSD_DEBUG("New slot allocated (type=%u, slot=%u).",
139		    type, i + 1);
140	}
141
142	osdm[type].osd_destructors[i] = destructor;
143	if (osdm[type].osd_nmethods != 0) {
144		for (m = 0; m < osdm[type].osd_nmethods; m++)
145			osdm[type].osd_methods[i * osdm[type].osd_nmethods + m]
146			    = methods != NULL ? methods[m] : NULL;
147	}
148	sx_xunlock(&osdm[type].osd_module_lock);
149	return (i + 1);
150}
151
152void
153osd_deregister(u_int type, u_int slot)
154{
155	struct osd *osd, *tosd;
156
157	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
158	KASSERT(slot > 0, ("Invalid slot."));
159	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
160
161	sx_xlock(&osdm[type].osd_module_lock);
162	rm_wlock(&osdm[type].osd_object_lock);
163	/*
164	 * Free all OSD for the given slot.
165	 */
166	mtx_lock(&osdm[type].osd_list_lock);
167	LIST_FOREACH_SAFE(osd, &osdm[type].osd_list, osd_next, tosd)
168		do_osd_del(type, osd, slot, 1);
169	mtx_unlock(&osdm[type].osd_list_lock);
170	/*
171	 * Set destructor to NULL to free the slot.
172	 */
173	osdm[type].osd_destructors[slot - 1] = NULL;
174	if (slot == osdm[type].osd_ntslots) {
175		osdm[type].osd_ntslots--;
176		osdm[type].osd_destructors = realloc(osdm[type].osd_destructors,
177		    sizeof(osd_destructor_t) * osdm[type].osd_ntslots, M_OSD,
178		    M_NOWAIT | M_ZERO);
179		if (osdm[type].osd_nmethods != 0)
180			osdm[type].osd_methods = realloc(osdm[type].osd_methods,
181			    sizeof(osd_method_t) * osdm[type].osd_ntslots *
182			    osdm[type].osd_nmethods, M_OSD, M_NOWAIT | M_ZERO);
183		/*
184		 * We always reallocate to smaller size, so we assume it will
185		 * always succeed.
186		 */
187		KASSERT(osdm[type].osd_destructors != NULL &&
188		    (osdm[type].osd_nmethods == 0 ||
189		     osdm[type].osd_methods != NULL), ("realloc() failed"));
190		OSD_DEBUG("Deregistration of the last slot (type=%u, slot=%u).",
191		    type, slot);
192	} else {
193		OSD_DEBUG("Slot deregistration (type=%u, slot=%u).",
194		    type, slot);
195	}
196	rm_wunlock(&osdm[type].osd_object_lock);
197	sx_xunlock(&osdm[type].osd_module_lock);
198}
199
200int
201osd_set(u_int type, struct osd *osd, u_int slot, void *value)
202{
203
204	return (osd_set_reserved(type, osd, slot, NULL, value));
205}
206
207void **
208osd_reserve(u_int slot)
209{
210
211	KASSERT(slot > 0, ("Invalid slot."));
212
213	OSD_DEBUG("Reserving slot array (slot=%u).", slot);
214	return (malloc(sizeof(void *) * slot, M_OSD, M_WAITOK | M_ZERO));
215}
216
217int
218osd_set_reserved(u_int type, struct osd *osd, u_int slot, void **rsv,
219    void *value)
220{
221	struct rm_priotracker tracker;
222
223	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
224	KASSERT(slot > 0, ("Invalid slot."));
225	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
226
227	rm_rlock(&osdm[type].osd_object_lock, &tracker);
228	if (slot > osd->osd_nslots) {
229		void **newptr;
230
231		if (value == NULL) {
232			OSD_DEBUG(
233			    "Not allocating null slot (type=%u, slot=%u).",
234			    type, slot);
235			rm_runlock(&osdm[type].osd_object_lock, &tracker);
236			if (rsv)
237				osd_free_reserved(rsv);
238			return (0);
239		}
240
241		/*
242		 * Too few slots allocated here, so we need to extend or create
243		 * the array.
244		 */
245		if (rsv) {
246			/*
247			 * Use the reserve passed in (assumed to be
248			 * the right size).
249			 */
250			newptr = rsv;
251			if (osd->osd_nslots != 0) {
252				memcpy(newptr, osd->osd_slots,
253				    sizeof(void *) * osd->osd_nslots);
254				free(osd->osd_slots, M_OSD);
255			}
256		} else {
257			newptr = realloc(osd->osd_slots, sizeof(void *) * slot,
258			    M_OSD, M_NOWAIT | M_ZERO);
259			if (newptr == NULL) {
260				rm_runlock(&osdm[type].osd_object_lock,
261				    &tracker);
262				return (ENOMEM);
263			}
264		}
265		if (osd->osd_nslots == 0) {
266			/*
267			 * First OSD for this object, so we need to put it
268			 * onto the list.
269			 */
270			mtx_lock(&osdm[type].osd_list_lock);
271			LIST_INSERT_HEAD(&osdm[type].osd_list, osd, osd_next);
272			mtx_unlock(&osdm[type].osd_list_lock);
273			OSD_DEBUG("Setting first slot (type=%u).", type);
274		} else
275			OSD_DEBUG("Growing slots array (type=%u).", type);
276		osd->osd_slots = newptr;
277		osd->osd_nslots = slot;
278	} else if (rsv)
279		osd_free_reserved(rsv);
280	OSD_DEBUG("Setting slot value (type=%u, slot=%u, value=%p).", type,
281	    slot, value);
282	osd->osd_slots[slot - 1] = value;
283	rm_runlock(&osdm[type].osd_object_lock, &tracker);
284	return (0);
285}
286
287void
288osd_free_reserved(void **rsv)
289{
290
291	OSD_DEBUG("Discarding reserved slot array.");
292	free(rsv, M_OSD);
293}
294
295void *
296osd_get(u_int type, struct osd *osd, u_int slot)
297{
298	struct rm_priotracker tracker;
299	void *value;
300
301	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
302	KASSERT(slot > 0, ("Invalid slot."));
303	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
304
305	rm_rlock(&osdm[type].osd_object_lock, &tracker);
306	if (slot > osd->osd_nslots) {
307		value = NULL;
308		OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
309	} else {
310		value = osd->osd_slots[slot - 1];
311		OSD_DEBUG("Returning slot value (type=%u, slot=%u, value=%p).",
312		    type, slot, value);
313	}
314	rm_runlock(&osdm[type].osd_object_lock, &tracker);
315	return (value);
316}
317
318void
319osd_del(u_int type, struct osd *osd, u_int slot)
320{
321	struct rm_priotracker tracker;
322
323	rm_rlock(&osdm[type].osd_object_lock, &tracker);
324	do_osd_del(type, osd, slot, 0);
325	rm_runlock(&osdm[type].osd_object_lock, &tracker);
326}
327
328static void
329do_osd_del(u_int type, struct osd *osd, u_int slot, int list_locked)
330{
331	int i;
332
333	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
334	KASSERT(slot > 0, ("Invalid slot."));
335	KASSERT(osdm[type].osd_destructors[slot - 1] != NULL, ("Unused slot."));
336
337	OSD_DEBUG("Deleting slot (type=%u, slot=%u).", type, slot);
338
339	if (slot > osd->osd_nslots) {
340		OSD_DEBUG("Slot doesn't exist (type=%u, slot=%u).", type, slot);
341		return;
342	}
343	if (osd->osd_slots[slot - 1] != NULL) {
344		osdm[type].osd_destructors[slot - 1](osd->osd_slots[slot - 1]);
345		osd->osd_slots[slot - 1] = NULL;
346	}
347	for (i = osd->osd_nslots - 1; i >= 0; i--) {
348		if (osd->osd_slots[i] != NULL) {
349			OSD_DEBUG("Slot still has a value (type=%u, slot=%u).",
350			    type, i + 1);
351			break;
352		}
353	}
354	if (i == -1) {
355		/* No values left for this object. */
356		OSD_DEBUG("No more slots left (type=%u).", type);
357		if (!list_locked)
358			mtx_lock(&osdm[type].osd_list_lock);
359		LIST_REMOVE(osd, osd_next);
360		if (!list_locked)
361			mtx_unlock(&osdm[type].osd_list_lock);
362		free(osd->osd_slots, M_OSD);
363		osd->osd_slots = NULL;
364		osd->osd_nslots = 0;
365	} else if (slot == osd->osd_nslots) {
366		/* This was the last slot. */
367		osd->osd_slots = realloc(osd->osd_slots,
368		    sizeof(void *) * (i + 1), M_OSD, M_NOWAIT | M_ZERO);
369		/*
370		 * We always reallocate to smaller size, so we assume it will
371		 * always succeed.
372		 */
373		KASSERT(osd->osd_slots != NULL, ("realloc() failed"));
374		osd->osd_nslots = i + 1;
375		OSD_DEBUG("Reducing slots array to %u (type=%u).",
376		    osd->osd_nslots, type);
377	}
378}
379
380int
381osd_call(u_int type, u_int method, void *obj, void *data)
382{
383	osd_method_t methodfun;
384	int error, i;
385
386	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
387	KASSERT(method < osdm[type].osd_nmethods, ("Invalid method."));
388
389	/*
390	 * Call this method for every slot that defines it, stopping if an
391	 * error is encountered.
392	 */
393	error = 0;
394	sx_slock(&osdm[type].osd_module_lock);
395	for (i = 0; i < osdm[type].osd_ntslots; i++) {
396		methodfun = osdm[type].osd_methods[i * osdm[type].osd_nmethods +
397		    method];
398		if (methodfun != NULL && (error = methodfun(obj, data)) != 0)
399			break;
400	}
401	sx_sunlock(&osdm[type].osd_module_lock);
402	return (error);
403}
404
405void
406osd_exit(u_int type, struct osd *osd)
407{
408	struct rm_priotracker tracker;
409	u_int i;
410
411	KASSERT(type >= OSD_FIRST && type <= OSD_LAST, ("Invalid type."));
412
413	if (osd->osd_nslots == 0) {
414		KASSERT(osd->osd_slots == NULL, ("Non-null osd_slots."));
415		/* No OSD attached, just leave. */
416		return;
417	}
418
419	rm_rlock(&osdm[type].osd_object_lock, &tracker);
420	for (i = 1; i <= osd->osd_nslots; i++) {
421		if (osdm[type].osd_destructors[i - 1] != NULL)
422			do_osd_del(type, osd, i, 0);
423		else
424			OSD_DEBUG("Unused slot (type=%u, slot=%u).", type, i);
425	}
426	rm_runlock(&osdm[type].osd_object_lock, &tracker);
427	OSD_DEBUG("Object exit (type=%u).", type);
428}
429
430static void
431osd_init(void *arg __unused)
432{
433	u_int i;
434
435	for (i = OSD_FIRST; i <= OSD_LAST; i++) {
436		sx_init(&osdm[i].osd_module_lock, "osd_module");
437		rm_init(&osdm[i].osd_object_lock, "osd_object");
438		mtx_init(&osdm[i].osd_list_lock, "osd_list", NULL, MTX_DEF);
439		LIST_INIT(&osdm[i].osd_list);
440		osdm[i].osd_destructors = NULL;
441		osdm[i].osd_ntslots = 0;
442		osdm[i].osd_methods = NULL;
443	}
444}
445SYSINIT(osd, SI_SUB_LOCK, SI_ORDER_ANY, osd_init, NULL);
446