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 39 /* Do QD, or 4 * CPUS, whatever is smallest */ 40 concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); 41 42 return io_wq_create(concurrency, &data); 43 } 44 45 void __io_uring_free(struct task_struct *tsk) 46 { 47 struct io_uring_task *tctx = tsk->io_uring; 48 struct io_tctx_node *node; 49 unsigned long index; 50 51 /* 52 * Fault injection forcing allocation errors in the xa_store() path 53 * can lead to xa_empty() returning false, even though no actual 54 * node is stored in the xarray. Until that gets sorted out, attempt 55 * an iteration here and warn if any entries are found. 56 */ 57 xa_for_each(&tctx->xa, index, node) { 58 WARN_ON_ONCE(1); 59 break; 60 } 61 WARN_ON_ONCE(tctx->io_wq); 62 WARN_ON_ONCE(tctx->cached_refs); 63 64 percpu_counter_destroy(&tctx->inflight); 65 kfree(tctx); 66 tsk->io_uring = NULL; 67 } 68 69 __cold int io_uring_alloc_task_context(struct task_struct *task, 70 struct io_ring_ctx *ctx) 71 { 72 struct io_uring_task *tctx; 73 int ret; 74 75 tctx = kzalloc(sizeof(*tctx), GFP_KERNEL); 76 if (unlikely(!tctx)) 77 return -ENOMEM; 78 79 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); 80 if (unlikely(ret)) { 81 kfree(tctx); 82 return ret; 83 } 84 85 tctx->io_wq = io_init_wq_offload(ctx, task); 86 if (IS_ERR(tctx->io_wq)) { 87 ret = PTR_ERR(tctx->io_wq); 88 percpu_counter_destroy(&tctx->inflight); 89 kfree(tctx); 90 return ret; 91 } 92 93 tctx->task = task; 94 xa_init(&tctx->xa); 95 init_waitqueue_head(&tctx->wait); 96 atomic_set(&tctx->in_cancel, 0); 97 atomic_set(&tctx->inflight_tracked, 0); 98 task->io_uring = tctx; 99 init_llist_head(&tctx->task_list); 100 init_task_work(&tctx->task_work, tctx_task_work); 101 return 0; 102 } 103 104 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) 105 { 106 struct io_uring_task *tctx = current->io_uring; 107 struct io_tctx_node *node; 108 int ret; 109 110 if (unlikely(!tctx)) { 111 ret = io_uring_alloc_task_context(current, ctx); 112 if (unlikely(ret)) 113 return ret; 114 115 tctx = current->io_uring; 116 if (ctx->iowq_limits_set) { 117 unsigned int limits[2] = { ctx->iowq_limits[0], 118 ctx->iowq_limits[1], }; 119 120 ret = io_wq_max_workers(tctx->io_wq, limits); 121 if (ret) 122 return ret; 123 } 124 } 125 if (!xa_load(&tctx->xa, (unsigned long)ctx)) { 126 node = kmalloc(sizeof(*node), GFP_KERNEL); 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->uring_lock); 140 list_add(&node->ctx_node, &ctx->tctx_list); 141 mutex_unlock(&ctx->uring_lock); 142 } 143 return 0; 144 } 145 146 int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) 147 { 148 int ret; 149 150 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER 151 && ctx->submitter_task != current) 152 return -EEXIST; 153 154 ret = __io_uring_add_tctx_node(ctx); 155 if (ret) 156 return ret; 157 158 current->io_uring->last = ctx; 159 return 0; 160 } 161 162 /* 163 * Remove this io_uring_file -> task mapping. 164 */ 165 __cold void io_uring_del_tctx_node(unsigned long index) 166 { 167 struct io_uring_task *tctx = current->io_uring; 168 struct io_tctx_node *node; 169 170 if (!tctx) 171 return; 172 node = xa_erase(&tctx->xa, index); 173 if (!node) 174 return; 175 176 WARN_ON_ONCE(current != node->task); 177 WARN_ON_ONCE(list_empty(&node->ctx_node)); 178 179 mutex_lock(&node->ctx->uring_lock); 180 list_del(&node->ctx_node); 181 mutex_unlock(&node->ctx->uring_lock); 182 183 if (tctx->last == node->ctx) 184 tctx->last = NULL; 185 kfree(node); 186 } 187 188 __cold void io_uring_clean_tctx(struct io_uring_task *tctx) 189 { 190 struct io_wq *wq = tctx->io_wq; 191 struct io_tctx_node *node; 192 unsigned long index; 193 194 xa_for_each(&tctx->xa, index, node) { 195 io_uring_del_tctx_node(index); 196 cond_resched(); 197 } 198 if (wq) { 199 /* 200 * Must be after io_uring_del_tctx_node() (removes nodes under 201 * uring_lock) to avoid race with io_uring_try_cancel_iowq(). 202 */ 203 io_wq_put_and_exit(wq); 204 tctx->io_wq = NULL; 205 } 206 } 207 208 void io_uring_unreg_ringfd(void) 209 { 210 struct io_uring_task *tctx = current->io_uring; 211 int i; 212 213 for (i = 0; i < IO_RINGFD_REG_MAX; i++) { 214 if (tctx->registered_rings[i]) { 215 fput(tctx->registered_rings[i]); 216 tctx->registered_rings[i] = NULL; 217 } 218 } 219 } 220 221 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, 222 int start, int end) 223 { 224 int offset; 225 for (offset = start; offset < end; offset++) { 226 offset = array_index_nospec(offset, IO_RINGFD_REG_MAX); 227 if (tctx->registered_rings[offset]) 228 continue; 229 230 tctx->registered_rings[offset] = file; 231 return offset; 232 } 233 return -EBUSY; 234 } 235 236 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, 237 int start, int end) 238 { 239 struct file *file; 240 int offset; 241 242 file = fget(fd); 243 if (!file) { 244 return -EBADF; 245 } else if (!io_is_uring_fops(file)) { 246 fput(file); 247 return -EOPNOTSUPP; 248 } 249 offset = io_ring_add_registered_file(tctx, file, start, end); 250 if (offset < 0) 251 fput(file); 252 return offset; 253 } 254 255 /* 256 * Register a ring fd to avoid fdget/fdput for each io_uring_enter() 257 * invocation. User passes in an array of struct io_uring_rsrc_update 258 * with ->data set to the ring_fd, and ->offset given for the desired 259 * index. If no index is desired, application may set ->offset == -1U 260 * and we'll find an available index. Returns number of entries 261 * successfully processed, or < 0 on error if none were processed. 262 */ 263 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, 264 unsigned nr_args) 265 { 266 struct io_uring_rsrc_update __user *arg = __arg; 267 struct io_uring_rsrc_update reg; 268 struct io_uring_task *tctx; 269 int ret, i; 270 271 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 272 return -EINVAL; 273 274 mutex_unlock(&ctx->uring_lock); 275 ret = __io_uring_add_tctx_node(ctx); 276 mutex_lock(&ctx->uring_lock); 277 if (ret) 278 return ret; 279 280 tctx = current->io_uring; 281 for (i = 0; i < nr_args; i++) { 282 int start, end; 283 284 if (copy_from_user(®, &arg[i], sizeof(reg))) { 285 ret = -EFAULT; 286 break; 287 } 288 289 if (reg.resv) { 290 ret = -EINVAL; 291 break; 292 } 293 294 if (reg.offset == -1U) { 295 start = 0; 296 end = IO_RINGFD_REG_MAX; 297 } else { 298 if (reg.offset >= IO_RINGFD_REG_MAX) { 299 ret = -EINVAL; 300 break; 301 } 302 start = reg.offset; 303 end = start + 1; 304 } 305 306 ret = io_ring_add_registered_fd(tctx, reg.data, start, end); 307 if (ret < 0) 308 break; 309 310 reg.offset = ret; 311 if (copy_to_user(&arg[i], ®, sizeof(reg))) { 312 fput(tctx->registered_rings[reg.offset]); 313 tctx->registered_rings[reg.offset] = NULL; 314 ret = -EFAULT; 315 break; 316 } 317 } 318 319 return i ? i : ret; 320 } 321 322 int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, 323 unsigned nr_args) 324 { 325 struct io_uring_rsrc_update __user *arg = __arg; 326 struct io_uring_task *tctx = current->io_uring; 327 struct io_uring_rsrc_update reg; 328 int ret = 0, i; 329 330 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 331 return -EINVAL; 332 if (!tctx) 333 return 0; 334 335 for (i = 0; i < nr_args; i++) { 336 if (copy_from_user(®, &arg[i], sizeof(reg))) { 337 ret = -EFAULT; 338 break; 339 } 340 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { 341 ret = -EINVAL; 342 break; 343 } 344 345 reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); 346 if (tctx->registered_rings[reg.offset]) { 347 fput(tctx->registered_rings[reg.offset]); 348 tctx->registered_rings[reg.offset] = NULL; 349 } 350 } 351 352 return i ? i : ret; 353 } 354