1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/kernel.h>
3 #include <linux/errno.h>
4 #include <linux/file.h>
6 #include <linux/slab.h>
7 #include <linux/nospec.h>
8 #include <linux/io_uring.h>
10 #include <uapi/linux/io_uring.h>
12 #include "io_uring_types.h"
16 static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx,
17 struct task_struct *task)
19 struct io_wq_hash *hash;
20 struct io_wq_data data;
21 unsigned int concurrency;
23 mutex_lock(&ctx->uring_lock);
26 hash = kzalloc(sizeof(*hash), GFP_KERNEL);
28 mutex_unlock(&ctx->uring_lock);
29 return ERR_PTR(-ENOMEM);
31 refcount_set(&hash->refs, 1);
32 init_waitqueue_head(&hash->wait);
35 mutex_unlock(&ctx->uring_lock);
39 data.free_work = io_wq_free_work;
40 data.do_work = io_wq_submit_work;
42 /* Do QD, or 4 * CPUS, whatever is smallest */
43 concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
45 return io_wq_create(concurrency, &data);
48 void __io_uring_free(struct task_struct *tsk)
50 struct io_uring_task *tctx = tsk->io_uring;
52 WARN_ON_ONCE(!xa_empty(&tctx->xa));
53 WARN_ON_ONCE(tctx->io_wq);
54 WARN_ON_ONCE(tctx->cached_refs);
56 percpu_counter_destroy(&tctx->inflight);
61 __cold int io_uring_alloc_task_context(struct task_struct *task,
62 struct io_ring_ctx *ctx)
64 struct io_uring_task *tctx;
67 tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
71 ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
77 tctx->io_wq = io_init_wq_offload(ctx, task);
78 if (IS_ERR(tctx->io_wq)) {
79 ret = PTR_ERR(tctx->io_wq);
80 percpu_counter_destroy(&tctx->inflight);
86 init_waitqueue_head(&tctx->wait);
87 atomic_set(&tctx->in_idle, 0);
88 atomic_set(&tctx->inflight_tracked, 0);
89 task->io_uring = tctx;
90 spin_lock_init(&tctx->task_lock);
91 INIT_WQ_LIST(&tctx->task_list);
92 INIT_WQ_LIST(&tctx->prio_task_list);
93 init_task_work(&tctx->task_work, tctx_task_work);
97 static int io_register_submitter(struct io_ring_ctx *ctx)
101 mutex_lock(&ctx->uring_lock);
102 if (!ctx->submitter_task)
103 ctx->submitter_task = get_task_struct(current);
104 else if (ctx->submitter_task != current)
106 mutex_unlock(&ctx->uring_lock);
111 int __io_uring_add_tctx_node(struct io_ring_ctx *ctx, bool submitter)
113 struct io_uring_task *tctx = current->io_uring;
114 struct io_tctx_node *node;
117 if ((ctx->flags & IORING_SETUP_SINGLE_ISSUER) && submitter) {
118 ret = io_register_submitter(ctx);
123 if (unlikely(!tctx)) {
124 ret = io_uring_alloc_task_context(current, ctx);
128 tctx = current->io_uring;
129 if (ctx->iowq_limits_set) {
130 unsigned int limits[2] = { ctx->iowq_limits[0],
131 ctx->iowq_limits[1], };
133 ret = io_wq_max_workers(tctx->io_wq, limits);
138 if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
139 node = kmalloc(sizeof(*node), GFP_KERNEL);
143 node->task = current;
145 ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,
152 mutex_lock(&ctx->uring_lock);
153 list_add(&node->ctx_node, &ctx->tctx_list);
154 mutex_unlock(&ctx->uring_lock);
162 * Remove this io_uring_file -> task mapping.
164 __cold void io_uring_del_tctx_node(unsigned long index)
166 struct io_uring_task *tctx = current->io_uring;
167 struct io_tctx_node *node;
171 node = xa_erase(&tctx->xa, index);
175 WARN_ON_ONCE(current != node->task);
176 WARN_ON_ONCE(list_empty(&node->ctx_node));
178 mutex_lock(&node->ctx->uring_lock);
179 list_del(&node->ctx_node);
180 mutex_unlock(&node->ctx->uring_lock);
182 if (tctx->last == node->ctx)
187 __cold void io_uring_clean_tctx(struct io_uring_task *tctx)
189 struct io_wq *wq = tctx->io_wq;
190 struct io_tctx_node *node;
193 xa_for_each(&tctx->xa, index, node) {
194 io_uring_del_tctx_node(index);
199 * Must be after io_uring_del_tctx_node() (removes nodes under
200 * uring_lock) to avoid race with io_uring_try_cancel_iowq().
202 io_wq_put_and_exit(wq);
207 void io_uring_unreg_ringfd(void)
209 struct io_uring_task *tctx = current->io_uring;
212 for (i = 0; i < IO_RINGFD_REG_MAX; i++) {
213 if (tctx->registered_rings[i]) {
214 fput(tctx->registered_rings[i]);
215 tctx->registered_rings[i] = NULL;
220 static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd,
226 for (offset = start; offset < end; offset++) {
227 offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
228 if (tctx->registered_rings[offset])
234 } else if (!io_is_uring_fops(file)) {
238 tctx->registered_rings[offset] = file;
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.
253 int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
256 struct io_uring_rsrc_update __user *arg = __arg;
257 struct io_uring_rsrc_update reg;
258 struct io_uring_task *tctx;
261 if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
264 mutex_unlock(&ctx->uring_lock);
265 ret = __io_uring_add_tctx_node(ctx, false);
266 mutex_lock(&ctx->uring_lock);
270 tctx = current->io_uring;
271 for (i = 0; i < nr_args; i++) {
274 if (copy_from_user(®, &arg[i], sizeof(reg))) {
284 if (reg.offset == -1U) {
286 end = IO_RINGFD_REG_MAX;
288 if (reg.offset >= IO_RINGFD_REG_MAX) {
296 ret = io_ring_add_registered_fd(tctx, reg.data, start, end);
301 if (copy_to_user(&arg[i], ®, sizeof(reg))) {
302 fput(tctx->registered_rings[reg.offset]);
303 tctx->registered_rings[reg.offset] = NULL;
312 int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
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;
320 if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
325 for (i = 0; i < nr_args; i++) {
326 if (copy_from_user(®, &arg[i], sizeof(reg))) {
330 if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) {
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;