1 /* $NetBSD: drm_vma_manager.c,v 1.3 2015/06/19 22:51:57 chs Exp $ */ 2 3 /*- 4 * Copyright (c) 2014 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Taylor R. Campbell. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 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 the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: drm_vma_manager.c,v 1.3 2015/06/19 22:51:57 chs Exp $"); 34 35 #include <sys/kmem.h> 36 #include <sys/rbtree.h> 37 #include <sys/vmem.h> 38 39 #include <drm/drm_vma_manager.h> 40 41 static int 42 drm_vma_node_compare(void *cookie __unused, const void *va, const void *vb) 43 { 44 const struct drm_vma_offset_node *const na = va; 45 const struct drm_vma_offset_node *const nb = vb; 46 47 if (na->von_startpage < nb->von_startpage) 48 return -1; 49 if (na->von_startpage > nb->von_startpage) 50 return +1; 51 return 0; 52 } 53 54 static int 55 drm_vma_node_compare_key(void *cookie __unused, const void *vn, const void *vk) 56 { 57 const struct drm_vma_offset_node *const n = vn; 58 const vmem_addr_t *const k = vk; 59 60 if (n->von_startpage < *k) 61 return -1; 62 if (n->von_startpage > *k) 63 return +1; 64 return 0; 65 } 66 67 static const rb_tree_ops_t drm_vma_node_rb_ops = { 68 .rbto_compare_nodes = &drm_vma_node_compare, 69 .rbto_compare_key = &drm_vma_node_compare_key, 70 .rbto_node_offset = offsetof(struct drm_vma_offset_node, von_rb_node), 71 .rbto_context = NULL, 72 }; 73 74 static int 75 drm_vma_file_compare(void *cookie __unused, const void *va, const void *vb) 76 { 77 const struct drm_vma_offset_file *const fa = va; 78 const struct drm_vma_offset_file *const fb = vb; 79 80 if (fa->vof_file < fb->vof_file) 81 return -1; 82 if (fa->vof_file > fb->vof_file) 83 return +1; 84 return 0; 85 } 86 87 static int 88 drm_vma_file_compare_key(void *cookie __unused, const void *vf, const void *vk) 89 { 90 const struct drm_vma_offset_file *const f = vf; 91 const struct file *const k = vk; 92 93 if (f->vof_file < k) 94 return -1; 95 if (f->vof_file > k) 96 return +1; 97 return 0; 98 } 99 100 static const rb_tree_ops_t drm_vma_file_rb_ops = { 101 .rbto_compare_nodes = &drm_vma_file_compare, 102 .rbto_compare_key = &drm_vma_file_compare_key, 103 .rbto_node_offset = offsetof(struct drm_vma_offset_file, vof_rb_node), 104 .rbto_context = NULL, 105 }; 106 107 void 108 drm_vma_offset_manager_init(struct drm_vma_offset_manager *mgr, 109 unsigned long startpage, unsigned long npages) 110 { 111 112 rw_init(&mgr->vom_lock); 113 rb_tree_init(&mgr->vom_nodes, &drm_vma_node_rb_ops); 114 mgr->vom_vmem = vmem_create("drm_vma", startpage, npages, 1, 115 NULL, NULL, NULL, 0, VM_SLEEP, IPL_NONE); 116 } 117 118 void 119 drm_vma_offset_manager_destroy(struct drm_vma_offset_manager *mgr) 120 { 121 122 vmem_destroy(mgr->vom_vmem); 123 #if 0 124 rb_tree_destroy(&mgr->vom_nodes); 125 #endif 126 rw_destroy(&mgr->vom_lock); 127 } 128 129 void 130 drm_vma_node_init(struct drm_vma_offset_node *node) 131 { 132 static const struct drm_vma_offset_node zero_node; 133 134 *node = zero_node; 135 136 rw_init(&node->von_lock); 137 node->von_startpage = 0; 138 node->von_npages = 0; 139 rb_tree_init(&node->von_files, &drm_vma_file_rb_ops); 140 } 141 142 void 143 drm_vma_node_destroy(struct drm_vma_offset_node *node) 144 { 145 146 #if 0 147 rb_tree_destroy(&node->von_files); 148 #endif 149 KASSERT(node->von_startpage == 0); 150 KASSERT(node->von_npages == 0); 151 rw_destroy(&node->von_lock); 152 } 153 154 int 155 drm_vma_offset_add(struct drm_vma_offset_manager *mgr, 156 struct drm_vma_offset_node *node, unsigned long npages) 157 { 158 vmem_size_t startpage; 159 struct drm_vma_offset_node *collision __diagused; 160 int error; 161 162 KASSERT(npages != 0); 163 164 if (0 < node->von_npages) 165 return 0; 166 167 error = vmem_alloc(mgr->vom_vmem, npages, VM_NOSLEEP|VM_BESTFIT, 168 &startpage); 169 if (error) { 170 if (error == ENOMEM) 171 error = ENOSPC; 172 /* XXX errno NetBSD->Linux */ 173 return -error; 174 } 175 176 node->von_startpage = startpage; 177 node->von_npages = npages; 178 179 rw_enter(&node->von_lock, RW_WRITER); 180 collision = rb_tree_insert_node(&mgr->vom_nodes, node); 181 KASSERT(collision == node); 182 rw_exit(&node->von_lock); 183 184 return 0; 185 } 186 187 void 188 drm_vma_offset_remove(struct drm_vma_offset_manager *mgr, 189 struct drm_vma_offset_node *node) 190 { 191 192 if (node->von_npages == 0) 193 return; 194 195 rw_enter(&node->von_lock, RW_WRITER); 196 rb_tree_remove_node(&mgr->vom_nodes, node); 197 rw_exit(&node->von_lock); 198 199 vmem_free(mgr->vom_vmem, node->von_startpage, node->von_npages); 200 201 node->von_npages = 0; 202 node->von_startpage = 0; 203 } 204 205 void 206 drm_vma_offset_lock_lookup(struct drm_vma_offset_manager *mgr) 207 { 208 209 rw_enter(&mgr->vom_lock, RW_READER); 210 } 211 212 void 213 drm_vma_offset_unlock_lookup(struct drm_vma_offset_manager *mgr) 214 { 215 216 rw_exit(&mgr->vom_lock); 217 } 218 219 struct drm_vma_offset_node * 220 drm_vma_offset_lookup_locked(struct drm_vma_offset_manager *mgr, 221 unsigned long startpage, unsigned long npages) 222 { 223 const vmem_addr_t key = startpage; 224 struct drm_vma_offset_node *node; 225 226 KASSERT(rw_lock_held(&mgr->vom_lock)); 227 228 node = rb_tree_find_node_leq(&mgr->vom_nodes, &key); 229 if (node == NULL) 230 return NULL; 231 KASSERT(node->von_startpage <= startpage); 232 if (npages < node->von_npages) 233 return NULL; 234 if (node->von_npages - npages < startpage - node->von_startpage) 235 return NULL; 236 237 return node; 238 } 239 240 struct drm_vma_offset_node * 241 drm_vma_offset_exact_lookup(struct drm_vma_offset_manager *mgr, 242 unsigned long startpage, unsigned long npages) 243 { 244 const vmem_addr_t key = startpage; 245 struct drm_vma_offset_node *node; 246 247 rw_enter(&mgr->vom_lock, RW_READER); 248 249 node = rb_tree_find_node(&mgr->vom_nodes, &key); 250 if (node == NULL) 251 goto out; 252 KASSERT(node->von_startpage == startpage); 253 if (node->von_npages != npages) { 254 node = NULL; 255 goto out; 256 } 257 258 out: rw_exit(&mgr->vom_lock); 259 return node; 260 } 261 262 int 263 drm_vma_node_allow(struct drm_vma_offset_node *node, struct file *file) 264 { 265 struct drm_vma_offset_file *new, *old; 266 267 new = kmem_alloc(sizeof(*new), KM_NOSLEEP); 268 if (new == NULL) 269 return -ENOMEM; 270 new->vof_file = file; 271 272 rw_enter(&node->von_lock, RW_WRITER); 273 old = rb_tree_insert_node(&node->von_files, new); 274 rw_exit(&node->von_lock); 275 276 if (old != new) /* collision */ 277 kmem_free(new, sizeof(*new)); 278 279 return 0; 280 } 281 282 void 283 drm_vma_node_revoke(struct drm_vma_offset_node *node, struct file *file) 284 { 285 286 rw_enter(&node->von_lock, RW_WRITER); 287 struct drm_vma_offset_file *const found = 288 rb_tree_find_node(&node->von_files, file); 289 if (found != NULL) 290 rb_tree_remove_node(&node->von_files, found); 291 rw_exit(&node->von_lock); 292 if (found != NULL) 293 kmem_free(found, sizeof(*found)); 294 } 295 296 bool 297 drm_vma_node_is_allowed(struct drm_vma_offset_node *node, struct file *file) 298 { 299 300 rw_enter(&node->von_lock, RW_READER); 301 const bool allowed = 302 (rb_tree_find_node(&node->von_files, file) != NULL); 303 rw_exit(&node->von_lock); 304 305 return allowed; 306 } 307 308 int 309 drm_vma_node_verify_access(struct drm_vma_offset_node *node, struct file *file) 310 { 311 312 if (!drm_vma_node_is_allowed(node, file)) 313 return -EACCES; 314 315 return 0; 316 } 317