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 51 WARN_ON_ONCE(!xa_empty(&tctx->xa)); 52 WARN_ON_ONCE(tctx->io_wq); 53 WARN_ON_ONCE(tctx->cached_refs); 54 55 percpu_counter_destroy(&tctx->inflight); 56 kfree(tctx); 57 tsk->io_uring = NULL; 58 } 59 60 __cold int io_uring_alloc_task_context(struct task_struct *task, 61 struct io_ring_ctx *ctx) 62 { 63 struct io_uring_task *tctx; 64 int ret; 65 66 tctx = kzalloc(sizeof(*tctx), GFP_KERNEL); 67 if (unlikely(!tctx)) 68 return -ENOMEM; 69 70 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); 71 if (unlikely(ret)) { 72 kfree(tctx); 73 return ret; 74 } 75 76 tctx->io_wq = io_init_wq_offload(ctx, task); 77 if (IS_ERR(tctx->io_wq)) { 78 ret = PTR_ERR(tctx->io_wq); 79 percpu_counter_destroy(&tctx->inflight); 80 kfree(tctx); 81 return ret; 82 } 83 84 xa_init(&tctx->xa); 85 init_waitqueue_head(&tctx->wait); 86 atomic_set(&tctx->in_cancel, 0); 87 atomic_set(&tctx->inflight_tracked, 0); 88 task->io_uring = tctx; 89 init_llist_head(&tctx->task_list); 90 init_task_work(&tctx->task_work, tctx_task_work); 91 return 0; 92 } 93 94 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) 95 { 96 struct io_uring_task *tctx = current->io_uring; 97 struct io_tctx_node *node; 98 int ret; 99 100 if (unlikely(!tctx)) { 101 ret = io_uring_alloc_task_context(current, ctx); 102 if (unlikely(ret)) 103 return ret; 104 105 tctx = current->io_uring; 106 if (ctx->iowq_limits_set) { 107 unsigned int limits[2] = { ctx->iowq_limits[0], 108 ctx->iowq_limits[1], }; 109 110 ret = io_wq_max_workers(tctx->io_wq, limits); 111 if (ret) 112 return ret; 113 } 114 } 115 if (!xa_load(&tctx->xa, (unsigned long)ctx)) { 116 node = kmalloc(sizeof(*node), GFP_KERNEL); 117 if (!node) 118 return -ENOMEM; 119 node->ctx = ctx; 120 node->task = current; 121 122 ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, 123 node, GFP_KERNEL)); 124 if (ret) { 125 kfree(node); 126 return ret; 127 } 128 129 mutex_lock(&ctx->uring_lock); 130 list_add(&node->ctx_node, &ctx->tctx_list); 131 mutex_unlock(&ctx->uring_lock); 132 } 133 return 0; 134 } 135 136 int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) 137 { 138 int ret; 139 140 if (ctx->flags & IORING_SETUP_SINGLE_ISSUER 141 && ctx->submitter_task != current) 142 return -EEXIST; 143 144 ret = __io_uring_add_tctx_node(ctx); 145 if (ret) 146 return ret; 147 148 current->io_uring->last = ctx; 149 return 0; 150 } 151 152 /* 153 * Remove this io_uring_file -> task mapping. 154 */ 155 __cold void io_uring_del_tctx_node(unsigned long index) 156 { 157 struct io_uring_task *tctx = current->io_uring; 158 struct io_tctx_node *node; 159 160 if (!tctx) 161 return; 162 node = xa_erase(&tctx->xa, index); 163 if (!node) 164 return; 165 166 WARN_ON_ONCE(current != node->task); 167 WARN_ON_ONCE(list_empty(&node->ctx_node)); 168 169 mutex_lock(&node->ctx->uring_lock); 170 list_del(&node->ctx_node); 171 mutex_unlock(&node->ctx->uring_lock); 172 173 if (tctx->last == node->ctx) 174 tctx->last = NULL; 175 kfree(node); 176 } 177 178 __cold void io_uring_clean_tctx(struct io_uring_task *tctx) 179 { 180 struct io_wq *wq = tctx->io_wq; 181 struct io_tctx_node *node; 182 unsigned long index; 183 184 xa_for_each(&tctx->xa, index, node) { 185 io_uring_del_tctx_node(index); 186 cond_resched(); 187 } 188 if (wq) { 189 /* 190 * Must be after io_uring_del_tctx_node() (removes nodes under 191 * uring_lock) to avoid race with io_uring_try_cancel_iowq(). 192 */ 193 io_wq_put_and_exit(wq); 194 tctx->io_wq = NULL; 195 } 196 } 197 198 void io_uring_unreg_ringfd(void) 199 { 200 struct io_uring_task *tctx = current->io_uring; 201 int i; 202 203 for (i = 0; i < IO_RINGFD_REG_MAX; i++) { 204 if (tctx->registered_rings[i]) { 205 fput(tctx->registered_rings[i]); 206 tctx->registered_rings[i] = NULL; 207 } 208 } 209 } 210 211 int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, 212 int start, int end) 213 { 214 int offset; 215 for (offset = start; offset < end; offset++) { 216 offset = array_index_nospec(offset, IO_RINGFD_REG_MAX); 217 if (tctx->registered_rings[offset]) 218 continue; 219 220 tctx->registered_rings[offset] = file; 221 return offset; 222 } 223 return -EBUSY; 224 } 225 226 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, 227 int start, int end) 228 { 229 struct file *file; 230 int offset; 231 232 file = fget(fd); 233 if (!file) { 234 return -EBADF; 235 } else if (!io_is_uring_fops(file)) { 236 fput(file); 237 return -EOPNOTSUPP; 238 } 239 offset = io_ring_add_registered_file(tctx, file, start, end); 240 if (offset < 0) 241 fput(file); 242 return offset; 243 } 244 245 /* 246 * Register a ring fd to avoid fdget/fdput for each io_uring_enter() 247 * invocation. User passes in an array of struct io_uring_rsrc_update 248 * with ->data set to the ring_fd, and ->offset given for the desired 249 * index. If no index is desired, application may set ->offset == -1U 250 * and we'll find an available index. Returns number of entries 251 * successfully processed, or < 0 on error if none were processed. 252 */ 253 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, 254 unsigned nr_args) 255 { 256 struct io_uring_rsrc_update __user *arg = __arg; 257 struct io_uring_rsrc_update reg; 258 struct io_uring_task *tctx; 259 int ret, i; 260 261 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 262 return -EINVAL; 263 264 mutex_unlock(&ctx->uring_lock); 265 ret = __io_uring_add_tctx_node(ctx); 266 mutex_lock(&ctx->uring_lock); 267 if (ret) 268 return ret; 269 270 tctx = current->io_uring; 271 for (i = 0; i < nr_args; i++) { 272 int start, end; 273 274 if (copy_from_user(®, &arg[i], sizeof(reg))) { 275 ret = -EFAULT; 276 break; 277 } 278 279 if (reg.resv) { 280 ret = -EINVAL; 281 break; 282 } 283 284 if (reg.offset == -1U) { 285 start = 0; 286 end = IO_RINGFD_REG_MAX; 287 } else { 288 if (reg.offset >= IO_RINGFD_REG_MAX) { 289 ret = -EINVAL; 290 break; 291 } 292 start = reg.offset; 293 end = start + 1; 294 } 295 296 ret = io_ring_add_registered_fd(tctx, reg.data, start, end); 297 if (ret < 0) 298 break; 299 300 reg.offset = ret; 301 if (copy_to_user(&arg[i], ®, sizeof(reg))) { 302 fput(tctx->registered_rings[reg.offset]); 303 tctx->registered_rings[reg.offset] = NULL; 304 ret = -EFAULT; 305 break; 306 } 307 } 308 309 return i ? i : ret; 310 } 311 312 int io_ringfd_unregister(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_task *tctx = current->io_uring; 317 struct io_uring_rsrc_update reg; 318 int ret = 0, i; 319 320 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 321 return -EINVAL; 322 if (!tctx) 323 return 0; 324 325 for (i = 0; i < nr_args; i++) { 326 if (copy_from_user(®, &arg[i], sizeof(reg))) { 327 ret = -EFAULT; 328 break; 329 } 330 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { 331 ret = -EINVAL; 332 break; 333 } 334 335 reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); 336 if (tctx->registered_rings[reg.offset]) { 337 fput(tctx->registered_rings[reg.offset]); 338 tctx->registered_rings[reg.offset] = NULL; 339 } 340 } 341 342 return i ? i : ret; 343 } 344