1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/errno.h> 4 #include <linux/file.h> 5 #include <linux/mm.h> 6 #include <linux/slab.h> 7 #include <linux/nospec.h> 8 #include <linux/io_uring.h> 9 10 #include <uapi/linux/io_uring.h> 11 12 #include "io_uring.h" 13 #include "tctx.h" 14 #include "bpf_filter.h" 15 16 static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, 17 struct task_struct *task) 18 { 19 struct io_wq_hash *hash; 20 struct io_wq_data data; 21 unsigned int concurrency; 22 23 mutex_lock(&ctx->uring_lock); 24 hash = ctx->hash_map; 25 if (!hash) { 26 hash = kzalloc_obj(*hash); 27 if (!hash) { 28 mutex_unlock(&ctx->uring_lock); 29 return ERR_PTR(-ENOMEM); 30 } 31 refcount_set(&hash->refs, 1); 32 init_waitqueue_head(&hash->wait); 33 ctx->hash_map = hash; 34 } 35 mutex_unlock(&ctx->uring_lock); 36 37 data.hash = hash; 38 data.task = task; 39 40 /* Do QD, or 4 * CPUS, whatever is smallest */ 41 concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); 42 43 return io_wq_create(concurrency, &data); 44 } 45 46 void io_uring_free_tctx(struct task_struct *tsk) 47 { 48 struct io_uring_task *tctx = tsk->io_uring; 49 struct io_tctx_node *node; 50 unsigned long index; 51 52 /* 53 * Fault injection forcing allocation errors in the xa_store() path 54 * can lead to xa_empty() returning false, even though no actual 55 * node is stored in the xarray. Until that gets sorted out, attempt 56 * an iteration here and warn if any entries are found. 57 */ 58 if (tctx) { 59 xa_for_each(&tctx->xa, index, node) { 60 WARN_ON_ONCE(1); 61 break; 62 } 63 WARN_ON_ONCE(tctx->io_wq); 64 WARN_ON_ONCE(tctx->cached_refs); 65 66 percpu_counter_destroy(&tctx->inflight); 67 kfree(tctx); 68 tsk->io_uring = NULL; 69 } 70 } 71 72 void __io_uring_free(struct task_struct *tsk) 73 { 74 io_uring_free_tctx(tsk); 75 if (tsk->io_uring_restrict) { 76 io_put_bpf_filters(tsk->io_uring_restrict); 77 kfree(tsk->io_uring_restrict); 78 tsk->io_uring_restrict = NULL; 79 } 80 } 81 82 __cold struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task, 83 struct io_ring_ctx *ctx) 84 { 85 struct io_uring_task *tctx; 86 int ret; 87 88 tctx = kzalloc_obj(*tctx); 89 if (unlikely(!tctx)) 90 return ERR_PTR(-ENOMEM); 91 92 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); 93 if (unlikely(ret)) { 94 kfree(tctx); 95 return ERR_PTR(ret); 96 } 97 98 tctx->io_wq = io_init_wq_offload(ctx, task); 99 if (IS_ERR(tctx->io_wq)) { 100 ret = PTR_ERR(tctx->io_wq); 101 percpu_counter_destroy(&tctx->inflight); 102 kfree(tctx); 103 return ERR_PTR(ret); 104 } 105 106 tctx->task = task; 107 xa_init(&tctx->xa); 108 init_waitqueue_head(&tctx->wait); 109 atomic_set(&tctx->in_cancel, 0); 110 atomic_set(&tctx->inflight_tracked, 0); 111 mpscq_init(&tctx->task_list, &tctx->task_head); 112 INIT_WORK(&tctx->fallback_work, io_tctx_fallback_work); 113 init_task_work(&tctx->task_work, tctx_task_work); 114 return tctx; 115 } 116 117 static int io_tctx_install_node(struct io_ring_ctx *ctx, 118 struct io_uring_task *tctx) 119 { 120 struct io_tctx_node *node; 121 int ret; 122 123 if (xa_load(&tctx->xa, (unsigned long)ctx)) 124 return 0; 125 126 node = kmalloc_obj(*node); 127 if (!node) 128 return -ENOMEM; 129 node->ctx = ctx; 130 node->task = current; 131 132 ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, 133 node, GFP_KERNEL)); 134 if (ret) { 135 kfree(node); 136 return ret; 137 } 138 139 mutex_lock(&ctx->tctx_lock); 140 list_add(&node->ctx_node, &ctx->tctx_list); 141 mutex_unlock(&ctx->tctx_lock); 142 return 0; 143 } 144 145 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) 146 { 147 struct io_uring_task *tctx = current->io_uring; 148 bool new_tctx = false; 149 int ret; 150 151 if (unlikely(!tctx)) { 152 tctx = io_uring_alloc_task_context(current, ctx); 153 if (IS_ERR(tctx)) 154 return PTR_ERR(tctx); 155 new_tctx = true; 156 157 if (data_race(ctx->int_flags) & IO_RING_F_IOWQ_LIMITS_SET) { 158 unsigned int limits[2]; 159 160 mutex_lock(&ctx->uring_lock); 161 limits[0] = ctx->iowq_limits[0]; 162 limits[1] = ctx->iowq_limits[1]; 163 mutex_unlock(&ctx->uring_lock); 164 165 ret = io_wq_max_workers(tctx->io_wq, limits); 166 if (ret) 167 goto err_free; 168 } 169 } 170 171 /* 172 * Re-activate io-wq keepalive on any new io_uring usage. The wq may have 173 * been marked for idle-exit when the task temporarily had no active 174 * io_uring instances. 175 */ 176 if (tctx->io_wq) 177 io_wq_set_exit_on_idle(tctx->io_wq, false); 178 179 if (new_tctx) 180 current->io_uring = tctx; 181 182 ret = io_tctx_install_node(ctx, tctx); 183 if (!ret) 184 return 0; 185 err_free: 186 if (new_tctx) { 187 current->io_uring = NULL; 188 if (tctx->io_wq) { 189 io_wq_exit_start(tctx->io_wq); 190 io_wq_put_and_exit(tctx->io_wq); 191 } 192 percpu_counter_destroy(&tctx->inflight); 193 kfree(tctx); 194 } 195 return ret; 196 } 197 198 int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) 199 { 200 int ret; 201 202 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER 203 && ctx->submitter_task != current) 204 return -EEXIST; 205 206 ret = __io_uring_add_tctx_node(ctx); 207 if (ret) 208 return ret; 209 210 current->io_uring->last = ctx; 211 return 0; 212 } 213 214 /* 215 * Remove this io_uring_file -> task mapping. 216 */ 217 __cold void io_uring_del_tctx_node(unsigned long index) 218 { 219 struct io_uring_task *tctx = current->io_uring; 220 struct io_tctx_node *node; 221 222 if (!tctx) 223 return; 224 node = xa_erase(&tctx->xa, index); 225 if (!node) 226 return; 227 228 WARN_ON_ONCE(current != node->task); 229 WARN_ON_ONCE(list_empty(&node->ctx_node)); 230 231 mutex_lock(&node->ctx->tctx_lock); 232 list_del(&node->ctx_node); 233 mutex_unlock(&node->ctx->tctx_lock); 234 235 if (tctx->last == node->ctx) 236 tctx->last = NULL; 237 kfree(node); 238 239 if (xa_empty(&tctx->xa) && tctx->io_wq) 240 io_wq_set_exit_on_idle(tctx->io_wq, true); 241 } 242 243 __cold void io_uring_clean_tctx(struct io_uring_task *tctx) 244 { 245 struct io_wq *wq = tctx->io_wq; 246 struct io_tctx_node *node; 247 unsigned long index; 248 249 xa_for_each(&tctx->xa, index, node) { 250 io_uring_del_tctx_node(index); 251 cond_resched(); 252 } 253 if (wq) { 254 /* 255 * Must be after io_uring_del_tctx_node() (removes nodes under 256 * uring_lock) to avoid race with io_uring_try_cancel_iowq(). 257 */ 258 io_wq_put_and_exit(wq); 259 tctx->io_wq = NULL; 260 } 261 } 262 263 void io_uring_unreg_ringfd(void) 264 { 265 struct io_uring_task *tctx = current->io_uring; 266 int i; 267 268 for (i = 0; i < IO_RINGFD_REG_MAX; i++) { 269 if (tctx->registered_rings[i]) { 270 fput(tctx->registered_rings[i]); 271 tctx->registered_rings[i] = NULL; 272 } 273 } 274 } 275 276 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, 277 int start, int end) 278 { 279 int offset, idx; 280 for (offset = start; offset < end; offset++) { 281 idx = array_index_nospec(offset, IO_RINGFD_REG_MAX); 282 if (tctx->registered_rings[idx]) 283 continue; 284 285 tctx->registered_rings[idx] = file; 286 return idx; 287 } 288 return -EBUSY; 289 } 290 291 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, 292 int start, int end) 293 { 294 struct file *file; 295 int offset; 296 297 file = fget(fd); 298 if (!file) { 299 return -EBADF; 300 } else if (!io_is_uring_fops(file)) { 301 fput(file); 302 return -EOPNOTSUPP; 303 } 304 offset = io_ring_add_registered_file(tctx, file, start, end); 305 if (offset < 0) 306 fput(file); 307 return offset; 308 } 309 310 /* 311 * Register a ring fd to avoid fdget/fdput for each io_uring_enter() 312 * invocation. User passes in an array of struct io_uring_rsrc_update 313 * with ->data set to the ring_fd, and ->offset given for the desired 314 * index. If no index is desired, application may set ->offset == -1U 315 * and we'll find an available index. Returns number of entries 316 * successfully processed, or < 0 on error if none were processed. 317 */ 318 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, 319 unsigned nr_args) 320 { 321 struct io_uring_rsrc_update __user *arg = __arg; 322 struct io_uring_rsrc_update reg; 323 struct io_uring_task *tctx; 324 int ret, i; 325 326 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 327 return -EINVAL; 328 329 mutex_unlock(&ctx->uring_lock); 330 ret = __io_uring_add_tctx_node(ctx); 331 mutex_lock(&ctx->uring_lock); 332 if (ret) 333 return ret; 334 335 tctx = current->io_uring; 336 for (i = 0; i < nr_args; i++) { 337 int start, end; 338 339 if (copy_from_user(®, &arg[i], sizeof(reg))) { 340 ret = -EFAULT; 341 break; 342 } 343 344 if (reg.resv) { 345 ret = -EINVAL; 346 break; 347 } 348 349 if (reg.offset == -1U) { 350 start = 0; 351 end = IO_RINGFD_REG_MAX; 352 } else { 353 if (reg.offset >= IO_RINGFD_REG_MAX) { 354 ret = -EINVAL; 355 break; 356 } 357 start = reg.offset; 358 end = start + 1; 359 } 360 361 ret = io_ring_add_registered_fd(tctx, reg.data, start, end); 362 if (ret < 0) 363 break; 364 365 reg.offset = ret; 366 if (copy_to_user(&arg[i], ®, sizeof(reg))) { 367 fput(tctx->registered_rings[reg.offset]); 368 tctx->registered_rings[reg.offset] = NULL; 369 ret = -EFAULT; 370 break; 371 } 372 } 373 374 return i ? i : ret; 375 } 376 377 int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, 378 unsigned nr_args) 379 { 380 struct io_uring_rsrc_update __user *arg = __arg; 381 struct io_uring_task *tctx = current->io_uring; 382 struct io_uring_rsrc_update reg; 383 int ret = 0, i; 384 385 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 386 return -EINVAL; 387 if (!tctx) 388 return 0; 389 390 for (i = 0; i < nr_args; i++) { 391 if (copy_from_user(®, &arg[i], sizeof(reg))) { 392 ret = -EFAULT; 393 break; 394 } 395 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { 396 ret = -EINVAL; 397 break; 398 } 399 400 reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); 401 if (tctx->registered_rings[reg.offset]) { 402 fput(tctx->registered_rings[reg.offset]); 403 tctx->registered_rings[reg.offset] = NULL; 404 } 405 } 406 407 return i ? i : ret; 408 } 409 410 int __io_uring_fork(struct task_struct *tsk) 411 { 412 struct io_restriction *res, *src = tsk->io_uring_restrict; 413 414 /* Don't leave it dangling on error */ 415 tsk->io_uring_restrict = NULL; 416 417 res = kzalloc_obj(*res, GFP_KERNEL_ACCOUNT); 418 if (!res) 419 return -ENOMEM; 420 421 tsk->io_uring_restrict = res; 422 io_restriction_clone(res, src); 423 return 0; 424 } 425