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