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