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 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, 212 int start, int end) 213 { 214 struct file *file; 215 int offset; 216 217 for (offset = start; offset < end; offset++) { 218 offset = array_index_nospec(offset, IO_RINGFD_REG_MAX); 219 if (tctx->registered_rings[offset]) 220 continue; 221 222 file = fget(fd); 223 if (!file) { 224 return -EBADF; 225 } else if (!io_is_uring_fops(file)) { 226 fput(file); 227 return -EOPNOTSUPP; 228 } 229 tctx->registered_rings[offset] = file; 230 return offset; 231 } 232 233 return -EBUSY; 234 } 235 236 /* 237 * Register a ring fd to avoid fdget/fdput for each io_uring_enter() 238 * invocation. User passes in an array of struct io_uring_rsrc_update 239 * with ->data set to the ring_fd, and ->offset given for the desired 240 * index. If no index is desired, application may set ->offset == -1U 241 * and we'll find an available index. Returns number of entries 242 * successfully processed, or < 0 on error if none were processed. 243 */ 244 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, 245 unsigned nr_args) 246 { 247 struct io_uring_rsrc_update __user *arg = __arg; 248 struct io_uring_rsrc_update reg; 249 struct io_uring_task *tctx; 250 int ret, i; 251 252 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 253 return -EINVAL; 254 255 mutex_unlock(&ctx->uring_lock); 256 ret = __io_uring_add_tctx_node(ctx); 257 mutex_lock(&ctx->uring_lock); 258 if (ret) 259 return ret; 260 261 tctx = current->io_uring; 262 for (i = 0; i < nr_args; i++) { 263 int start, end; 264 265 if (copy_from_user(®, &arg[i], sizeof(reg))) { 266 ret = -EFAULT; 267 break; 268 } 269 270 if (reg.resv) { 271 ret = -EINVAL; 272 break; 273 } 274 275 if (reg.offset == -1U) { 276 start = 0; 277 end = IO_RINGFD_REG_MAX; 278 } else { 279 if (reg.offset >= IO_RINGFD_REG_MAX) { 280 ret = -EINVAL; 281 break; 282 } 283 start = reg.offset; 284 end = start + 1; 285 } 286 287 ret = io_ring_add_registered_fd(tctx, reg.data, start, end); 288 if (ret < 0) 289 break; 290 291 reg.offset = ret; 292 if (copy_to_user(&arg[i], ®, sizeof(reg))) { 293 fput(tctx->registered_rings[reg.offset]); 294 tctx->registered_rings[reg.offset] = NULL; 295 ret = -EFAULT; 296 break; 297 } 298 } 299 300 return i ? i : ret; 301 } 302 303 int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, 304 unsigned nr_args) 305 { 306 struct io_uring_rsrc_update __user *arg = __arg; 307 struct io_uring_task *tctx = current->io_uring; 308 struct io_uring_rsrc_update reg; 309 int ret = 0, i; 310 311 if (!nr_args || nr_args > IO_RINGFD_REG_MAX) 312 return -EINVAL; 313 if (!tctx) 314 return 0; 315 316 for (i = 0; i < nr_args; i++) { 317 if (copy_from_user(®, &arg[i], sizeof(reg))) { 318 ret = -EFAULT; 319 break; 320 } 321 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { 322 ret = -EINVAL; 323 break; 324 } 325 326 reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); 327 if (tctx->registered_rings[reg.offset]) { 328 fput(tctx->registered_rings[reg.offset]); 329 tctx->registered_rings[reg.offset] = NULL; 330 } 331 } 332 333 return i ? i : ret; 334 } 335