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 15 static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, 16 struct task_struct *task) 17 { 18 struct io_wq_hash *hash; 19 struct io_wq_data data; 20 unsigned int concurrency; 21 22 mutex_lock(&ctx->uring_lock); 23 hash = ctx->hash_map; 24 if (!hash) { 25 hash = kzalloc(sizeof(*hash), GFP_KERNEL); 26 if (!hash) { 27 mutex_unlock(&ctx->uring_lock); 28 return ERR_PTR(-ENOMEM); 29 } 30 refcount_set(&hash->refs, 1); 31 init_waitqueue_head(&hash->wait); 32 ctx->hash_map = hash; 33 } 34 mutex_unlock(&ctx->uring_lock); 35 36 data.hash = hash; 37 data.task = task; 38 data.free_work = io_wq_free_work; 39 data.do_work = io_wq_submit_work; 40 41 /* Do QD, or 4 * CPUS, whatever is smallest */ 42 concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); 43 44 return io_wq_create(concurrency, &data); 45 } 46 47 void __io_uring_free(struct task_struct *tsk) 48 { 49 struct io_uring_task *tctx = tsk->io_uring; 50 struct io_tctx_node *node; 51 unsigned long index; 52 53 /* 54 * Fault injection forcing allocation errors in the xa_store() path 55 * can lead to xa_empty() returning false, even though no actual 56 * node is stored in the xarray. Until that gets sorted out, attempt 57 * an iteration here and warn if any entries are found. 58 */ 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 __cold int io_uring_alloc_task_context(struct task_struct *task, 72 struct io_ring_ctx *ctx) 73 { 74 struct io_uring_task *tctx; 75 int ret; 76 77 tctx = kzalloc(sizeof(*tctx), GFP_KERNEL); 78 if (unlikely(!tctx)) 79 return -ENOMEM; 80 81 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); 82 if (unlikely(ret)) { 83 kfree(tctx); 84 return ret; 85 } 86 87 tctx->io_wq = io_init_wq_offload(ctx, task); 88 if (IS_ERR(tctx->io_wq)) { 89 ret = PTR_ERR(tctx->io_wq); 90 percpu_counter_destroy(&tctx->inflight); 91 kfree(tctx); 92 return ret; 93 } 94 95 tctx->task = task; 96 xa_init(&tctx->xa); 97 init_waitqueue_head(&tctx->wait); 98 atomic_set(&tctx->in_cancel, 0); 99 atomic_set(&tctx->inflight_tracked, 0); 100 task->io_uring = tctx; 101 init_llist_head(&tctx->task_list); 102 init_task_work(&tctx->task_work, tctx_task_work); 103 return 0; 104 } 105 106 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) 107 { 108 struct io_uring_task *tctx = current->io_uring; 109 struct io_tctx_node *node; 110 int ret; 111 112 if (unlikely(!tctx)) { 113 ret = io_uring_alloc_task_context(current, ctx); 114 if (unlikely(ret)) 115 return ret; 116 117 tctx = current->io_uring; 118 if (ctx->iowq_limits_set) { 119 unsigned int limits[2] = { ctx->iowq_limits[0], 120 ctx->iowq_limits[1], }; 121 122 ret = io_wq_max_workers(tctx->io_wq, limits); 123 if (ret) 124 return ret; 125 } 126 } 127 if (!xa_load(&tctx->xa, (unsigned long)ctx)) { 128 node = kmalloc(sizeof(*node), GFP_KERNEL); 129 if (!node) 130 return -ENOMEM; 131 node->ctx = ctx; 132 node->task = current; 133 134 ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, 135 node, GFP_KERNEL)); 136 if (ret) { 137 kfree(node); 138 return ret; 139 } 140 141 mutex_lock(&ctx->uring_lock); 142 list_add(&node->ctx_node, &ctx->tctx_list); 143 mutex_unlock(&ctx->uring_lock); 144 } 145 return 0; 146 } 147 148 int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) 149 { 150 int ret; 151 152 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER 153 && ctx->submitter_task != current) 154 return -EEXIST; 155 156 ret = __io_uring_add_tctx_node(ctx); 157 if (ret) 158 return ret; 159 160 current->io_uring->last = ctx; 161 return 0; 162 } 163 164 /* 165 * Remove this io_uring_file -> task mapping. 166 */ 167 __cold void io_uring_del_tctx_node(unsigned long index) 168 { 169 struct io_uring_task *tctx = current->io_uring; 170 struct io_tctx_node *node; 171 172 if (!tctx) 173 return; 174 node = xa_erase(&tctx->xa, index); 175 if (!node) 176 return; 177 178 WARN_ON_ONCE(current != node->task); 179 WARN_ON_ONCE(list_empty(&node->ctx_node)); 180 181 mutex_lock(&node->ctx->uring_lock); 182 list_del(&node->ctx_node); 183 mutex_unlock(&node->ctx->uring_lock); 184 185 if (tctx->last == node->ctx) 186 tctx->last = NULL; 187 kfree(node); 188 } 189 190 __cold void io_uring_clean_tctx(struct io_uring_task *tctx) 191 { 192 struct io_wq *wq = tctx->io_wq; 193 struct io_tctx_node *node; 194 unsigned long index; 195 196 xa_for_each(&tctx->xa, index, node) { 197 io_uring_del_tctx_node(index); 198 cond_resched(); 199 } 200 if (wq) { 201 /* 202 * Must be after io_uring_del_tctx_node() (removes nodes under 203 * uring_lock) to avoid race with io_uring_try_cancel_iowq(). 204 */ 205 io_wq_put_and_exit(wq); 206 tctx->io_wq = NULL; 207 } 208 } 209 210 void io_uring_unreg_ringfd(void) 211 { 212 struct io_uring_task *tctx = current->io_uring; 213 int i; 214 215 for (i = 0; i < IO_RINGFD_REG_MAX; i++) { 216 if (tctx->registered_rings[i]) { 217 fput(tctx->registered_rings[i]); 218 tctx->registered_rings[i] = NULL; 219 } 220 } 221 } 222 223 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, 224 int start, int end) 225 { 226 int offset; 227 for (offset = start; offset < end; offset++) { 228 offset = array_index_nospec(offset, IO_RINGFD_REG_MAX); 229 if (tctx->registered_rings[offset]) 230 continue; 231 232 tctx->registered_rings[offset] = file; 233 return offset; 234 } 235 return -EBUSY; 236 } 237 238 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, 239 int start, int end) 240 { 241 struct file *file; 242 int offset; 243 244 file = fget(fd); 245 if (!file) { 246 return -EBADF; 247 } else if (!io_is_uring_fops(file)) { 248 fput(file); 249 return -EOPNOTSUPP; 250 } 251 offset = io_ring_add_registered_file(tctx, file, start, end); 252 if (offset < 0) 253 fput(file); 254 return offset; 255 } 256 257 /* 258 * Register a ring fd to avoid fdget/fdput for each io_uring_enter() 259 * invocation. User passes in an array of struct io_uring_rsrc_update 260 * with ->data set to the ring_fd, and ->offset given for the desired 261 * index. If no index is desired, application may set ->offset == -1U 262 * and we'll find an available index. Returns number of entries 263 * successfully processed, or < 0 on error if none were processed. 264 */ 265 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, 266 unsigned nr_args) 267 { 268 struct io_uring_rsrc_update __user *arg = __arg; 269 struct io_uring_rsrc_update reg; 270 struct io_uring_task *tctx; 271 int ret, i; 272 273 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 274 return -EINVAL; 275 276 mutex_unlock(&ctx->uring_lock); 277 ret = __io_uring_add_tctx_node(ctx); 278 mutex_lock(&ctx->uring_lock); 279 if (ret) 280 return ret; 281 282 tctx = current->io_uring; 283 for (i = 0; i < nr_args; i++) { 284 int start, end; 285 286 if (copy_from_user(®, &arg[i], sizeof(reg))) { 287 ret = -EFAULT; 288 break; 289 } 290 291 if (reg.resv) { 292 ret = -EINVAL; 293 break; 294 } 295 296 if (reg.offset == -1U) { 297 start = 0; 298 end = IO_RINGFD_REG_MAX; 299 } else { 300 if (reg.offset >= IO_RINGFD_REG_MAX) { 301 ret = -EINVAL; 302 break; 303 } 304 start = reg.offset; 305 end = start + 1; 306 } 307 308 ret = io_ring_add_registered_fd(tctx, reg.data, start, end); 309 if (ret < 0) 310 break; 311 312 reg.offset = ret; 313 if (copy_to_user(&arg[i], ®, sizeof(reg))) { 314 fput(tctx->registered_rings[reg.offset]); 315 tctx->registered_rings[reg.offset] = NULL; 316 ret = -EFAULT; 317 break; 318 } 319 } 320 321 return i ? i : ret; 322 } 323 324 int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, 325 unsigned nr_args) 326 { 327 struct io_uring_rsrc_update __user *arg = __arg; 328 struct io_uring_task *tctx = current->io_uring; 329 struct io_uring_rsrc_update reg; 330 int ret = 0, i; 331 332 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 333 return -EINVAL; 334 if (!tctx) 335 return 0; 336 337 for (i = 0; i < nr_args; i++) { 338 if (copy_from_user(®, &arg[i], sizeof(reg))) { 339 ret = -EFAULT; 340 break; 341 } 342 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { 343 ret = -EINVAL; 344 break; 345 } 346 347 reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); 348 if (tctx->registered_rings[reg.offset]) { 349 fput(tctx->registered_rings[reg.offset]); 350 tctx->registered_rings[reg.offset] = NULL; 351 } 352 } 353 354 return i ? i : ret; 355 } 356