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