2 * Copyright (c) 2005-2012 The DragonFly Project.
3 * Copyright (c) 2013 François Tigeot
6 * This code is derived from software contributed to The DragonFly Project
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in
17 * the documentation and/or other materials provided with the
19 * 3. Neither the name of The DragonFly Project nor the names of its
20 * contributors may be used to endorse or promote products derived
21 * from this software without specific, prior written permission.
23 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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39 #include <sys/kernel.h>
40 #include <sys/libkern.h>
41 #include <sys/malloc.h>
42 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <sys/spinlock2.h>
45 #include <sys/limits.h>
47 #define IDR_DEFAULT_SIZE 256
49 MALLOC_DEFINE(M_IDR, "idr", "Integer ID management");
51 static void idr_grow(struct idr *idp, int want);
52 static void idr_reserve(struct idr *idp, int id, int incr);
53 static void idr_set(struct idr *idp, int id, void *ptr);
54 static int idr_find_free(struct idr *idp, int want, int lim);
55 static int idr_pre_get1(struct idr *idp, int want, int lim);
58 * Number of nodes in right subtree, including the root.
61 right_subtree_size(int n)
63 return (n ^ (n | (n + 1)));
81 return ((n & (n + 1)) - 1);
85 idrfixup(struct idr *idp, int id)
87 if (id < idp->idr_freeindex) {
88 idp->idr_freeindex = id;
90 while (idp->idr_lastindex >= 0 &&
91 idp->idr_nodes[idp->idr_lastindex].data == NULL &&
92 idp->idr_nodes[idp->idr_lastindex].reserved == 0
98 static __inline struct idr_node *
99 idr_get_node(struct idr *idp, int id)
101 struct idr_node *idrnp;
102 if (id >= idp->idr_count)
104 idrnp = &idp->idr_nodes[id];
105 if (idrnp->allocated == 0)
111 idr_reserve(struct idr *idp, int id, int incr)
114 idp->idr_nodes[id].allocated += incr;
115 KKASSERT(idp->idr_nodes[id].allocated >= 0);
116 id = left_ancestor(id);
121 idr_find_free(struct idr *idp, int want, int lim)
123 int id, rsum, rsize, node;
126 * Search for a free descriptor starting at the higher
127 * of want or fd_freefile. If that fails, consider
128 * expanding the ofile array.
130 * NOTE! the 'allocated' field is a cumulative recursive allocation
131 * count. If we happen to see a value of 0 then we can shortcut
132 * our search. Otherwise we run through through the tree going
133 * down branches we know have free descriptor(s) until we hit a
134 * leaf node. The leaf node will be free but will not necessarily
135 * have an allocated field of 0.
138 /* move up the tree looking for a subtree with a free node */
139 for (id = max(want, idp->idr_freeindex); id < min(idp->idr_count, lim);
140 id = right_ancestor(id)) {
141 if (idp->idr_nodes[id].allocated == 0)
144 rsize = right_subtree_size(id);
145 if (idp->idr_nodes[id].allocated == rsize)
146 continue; /* right subtree full */
149 * Free fd is in the right subtree of the tree rooted at fd.
150 * Call that subtree R. Look for the smallest (leftmost)
151 * subtree of R with an unallocated fd: continue moving
152 * down the left branch until encountering a full left
153 * subtree, then move to the right.
155 for (rsum = 0, rsize /= 2; rsize > 0; rsize /= 2) {
157 rsum += idp->idr_nodes[node].allocated;
158 if (idp->idr_nodes[id].allocated == rsum + rsize) {
159 id = node; /* move to the right */
160 if (idp->idr_nodes[node].allocated == 0)
171 idr_pre_get1(struct idr *idp, int want, int lim)
175 if (want >= idp->idr_count)
179 id = idr_find_free(idp, want, lim);
184 * No space in current array. Expand?
186 if (idp->idr_count >= lim) {
197 idr_pre_get(struct idr *idp, __unused unsigned gfp_mask)
199 lwkt_gettoken(&idp->idr_token);
200 int error = idr_pre_get1(idp, idp->idr_maxwant, INT_MAX);
201 lwkt_reltoken(&idp->idr_token);
206 idr_get_new_above(struct idr *idp, void *ptr, int sid, int *id)
210 KKASSERT(ptr != NULL);
212 lwkt_gettoken(&idp->idr_token);
213 if (sid >= idp->idr_count) {
214 idp->idr_maxwant = max(idp->idr_maxwant, sid);
215 lwkt_reltoken(&idp->idr_token);
219 resid = idr_find_free(idp, sid, INT_MAX);
221 lwkt_reltoken(&idp->idr_token);
225 if (resid >= idp->idr_count)
226 idr_grow(idp, resid);
227 if (resid > idp->idr_lastindex)
228 idp->idr_lastindex = resid;
229 if (sid <= idp->idr_freeindex)
230 idp->idr_freeindex = resid;
232 KKASSERT(idp->idr_nodes[resid].reserved == 0);
233 idp->idr_nodes[resid].reserved = 1;
234 idr_reserve(idp, resid, 1);
235 idr_set(idp, resid, ptr);
237 lwkt_reltoken(&idp->idr_token);
242 idr_get_new(struct idr *idp, void *ptr, int *id)
244 return idr_get_new_above(idp, ptr, 0, id);
248 * Grow the file table so it can hold through descriptor (want).
251 idr_grow(struct idr *idp, int want)
253 struct idr_node *oldnodes, *newnodes;
256 /* We want 2^n descriptors */
260 } while (nf <= want);
262 /* Allocate a new zero'ed node array */
263 newnodes = kmalloc(nf * sizeof(struct idr_node), M_IDR, M_ZERO|M_WAITOK);
265 /* Copy the existing nodes at the beginning of the new array */
266 if (idp->idr_nodes != NULL)
267 bcopy(idp->idr_nodes, newnodes, idp->idr_count * sizeof(struct idr_node));
269 oldnodes = idp->idr_nodes;
270 idp->idr_nodes = newnodes;
273 if (oldnodes != NULL) {
274 kfree(oldnodes, M_IDR);
281 idr_remove(struct idr *idp, int id)
285 lwkt_gettoken(&idp->idr_token);
287 if (id >= idp->idr_count)
289 if ((ptr = idp->idr_nodes[id].data) == NULL)
291 idp->idr_nodes[id].data = NULL;
293 idr_reserve(idp, id, -1);
297 lwkt_reltoken(&idp->idr_token);
301 idr_remove_all(struct idr *idp)
303 kfree(idp->idr_nodes, M_IDR);
304 idp->idr_nodes = kmalloc(idp->idr_count * sizeof *idp, M_IDR, M_WAITOK | M_ZERO);
305 idp->idr_lastindex = -1;
306 idp->idr_freeindex = 0;
307 idp->idr_nexpands = 0;
308 idp->idr_maxwant = 0;
312 idr_destroy(struct idr *idp)
314 lwkt_token_uninit(&idp->idr_token);
315 kfree(idp->idr_nodes, M_IDR);
316 memset(idp, 0, sizeof(struct idr));
320 idr_find(struct idr *idp, int id)
324 lwkt_gettoken(&idp->idr_token);
326 if (id > idp->idr_count) {
328 } else if (idp->idr_nodes[id].allocated == 0) {
331 ret = idp->idr_nodes[id].data;
334 lwkt_reltoken(&idp->idr_token);
339 idr_set(struct idr *idp, int id, void *ptr)
341 KKASSERT(id < idp->idr_count);
342 KKASSERT(idp->idr_nodes[id].reserved != 0);
344 idp->idr_nodes[id].data = ptr;
345 idp->idr_nodes[id].reserved = 0;
347 idp->idr_nodes[id].reserved = 0;
348 idr_reserve(idp, id, -1);
354 idr_for_each(struct idr *idp, int (*fn)(int id, void *p, void *data), void *data)
357 struct idr_node *nodes = idp->idr_nodes;
359 lwkt_gettoken(&idp->idr_token);
360 for (i = 0; i < idp->idr_count; i++) {
361 if (nodes[i].data != NULL && nodes[i].allocated > 0) {
362 error = fn(i, nodes[i].data, data);
368 lwkt_reltoken(&idp->idr_token);
373 idr_replace(struct idr *idp, void *ptr, int id)
375 struct idr_node *idrnp;
378 lwkt_gettoken(&idp->idr_token);
380 idrnp = idr_get_node(idp, id);
381 if (idrnp == NULL || ptr == NULL)
388 lwkt_reltoken(&idp->idr_token);
393 idr_init(struct idr *idp)
395 bzero(idp, sizeof(struct idr));
396 idp->idr_nodes = kmalloc(IDR_DEFAULT_SIZE * sizeof(*idp),
397 M_IDR, M_WAITOK | M_ZERO);
398 idp->idr_count = IDR_DEFAULT_SIZE;
399 idp->idr_lastindex = -1;
400 idp->idr_maxwant = 0;
401 lwkt_token_init(&idp->idr_token, "idr token");