341 lines
7.4 KiB
C
341 lines
7.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/file.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/nospec.h>
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#include <linux/io_uring.h>
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#include <uapi/linux/io_uring.h>
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#include "io_uring.h"
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#include "tctx.h"
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static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx,
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struct task_struct *task)
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{
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struct io_wq_hash *hash;
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struct io_wq_data data;
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unsigned int concurrency;
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mutex_lock(&ctx->uring_lock);
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hash = ctx->hash_map;
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if (!hash) {
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hash = kzalloc(sizeof(*hash), GFP_KERNEL);
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if (!hash) {
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mutex_unlock(&ctx->uring_lock);
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return ERR_PTR(-ENOMEM);
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}
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refcount_set(&hash->refs, 1);
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init_waitqueue_head(&hash->wait);
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ctx->hash_map = hash;
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}
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mutex_unlock(&ctx->uring_lock);
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data.hash = hash;
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data.task = task;
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data.free_work = io_wq_free_work;
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data.do_work = io_wq_submit_work;
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/* Do QD, or 4 * CPUS, whatever is smallest */
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concurrency = min(ctx->sq_entries, 4 * num_online_cpus());
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return io_wq_create(concurrency, &data);
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}
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void __io_uring_free(struct task_struct *tsk)
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{
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struct io_uring_task *tctx = tsk->io_uring;
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WARN_ON_ONCE(!xa_empty(&tctx->xa));
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WARN_ON_ONCE(tctx->io_wq);
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WARN_ON_ONCE(tctx->cached_refs);
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percpu_counter_destroy(&tctx->inflight);
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kfree(tctx);
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tsk->io_uring = NULL;
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}
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__cold int io_uring_alloc_task_context(struct task_struct *task,
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struct io_ring_ctx *ctx)
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{
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struct io_uring_task *tctx;
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int ret;
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tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
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if (unlikely(!tctx))
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return -ENOMEM;
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ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
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if (unlikely(ret)) {
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kfree(tctx);
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return ret;
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}
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tctx->io_wq = io_init_wq_offload(ctx, task);
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if (IS_ERR(tctx->io_wq)) {
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ret = PTR_ERR(tctx->io_wq);
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percpu_counter_destroy(&tctx->inflight);
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kfree(tctx);
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return ret;
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}
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xa_init(&tctx->xa);
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init_waitqueue_head(&tctx->wait);
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atomic_set(&tctx->in_idle, 0);
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atomic_set(&tctx->inflight_tracked, 0);
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task->io_uring = tctx;
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init_llist_head(&tctx->task_list);
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init_task_work(&tctx->task_work, tctx_task_work);
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return 0;
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}
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static int io_register_submitter(struct io_ring_ctx *ctx)
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{
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int ret = 0;
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mutex_lock(&ctx->uring_lock);
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if (!ctx->submitter_task)
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ctx->submitter_task = get_task_struct(current);
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else if (ctx->submitter_task != current)
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ret = -EEXIST;
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mutex_unlock(&ctx->uring_lock);
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return ret;
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}
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int __io_uring_add_tctx_node(struct io_ring_ctx *ctx, bool submitter)
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{
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struct io_uring_task *tctx = current->io_uring;
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struct io_tctx_node *node;
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int ret;
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if ((ctx->flags & IORING_SETUP_SINGLE_ISSUER) && submitter) {
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ret = io_register_submitter(ctx);
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if (ret)
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return ret;
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}
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if (unlikely(!tctx)) {
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ret = io_uring_alloc_task_context(current, ctx);
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if (unlikely(ret))
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return ret;
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tctx = current->io_uring;
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if (ctx->iowq_limits_set) {
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unsigned int limits[2] = { ctx->iowq_limits[0],
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ctx->iowq_limits[1], };
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ret = io_wq_max_workers(tctx->io_wq, limits);
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if (ret)
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return ret;
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}
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}
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if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
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node = kmalloc(sizeof(*node), GFP_KERNEL);
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if (!node)
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return -ENOMEM;
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node->ctx = ctx;
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node->task = current;
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ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx,
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node, GFP_KERNEL));
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if (ret) {
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kfree(node);
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return ret;
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}
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mutex_lock(&ctx->uring_lock);
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list_add(&node->ctx_node, &ctx->tctx_list);
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mutex_unlock(&ctx->uring_lock);
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}
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if (submitter)
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tctx->last = ctx;
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return 0;
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}
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/*
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* Remove this io_uring_file -> task mapping.
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*/
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__cold void io_uring_del_tctx_node(unsigned long index)
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{
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struct io_uring_task *tctx = current->io_uring;
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struct io_tctx_node *node;
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if (!tctx)
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return;
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node = xa_erase(&tctx->xa, index);
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if (!node)
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return;
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WARN_ON_ONCE(current != node->task);
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WARN_ON_ONCE(list_empty(&node->ctx_node));
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mutex_lock(&node->ctx->uring_lock);
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list_del(&node->ctx_node);
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mutex_unlock(&node->ctx->uring_lock);
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if (tctx->last == node->ctx)
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tctx->last = NULL;
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kfree(node);
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}
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__cold void io_uring_clean_tctx(struct io_uring_task *tctx)
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{
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struct io_wq *wq = tctx->io_wq;
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struct io_tctx_node *node;
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unsigned long index;
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xa_for_each(&tctx->xa, index, node) {
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io_uring_del_tctx_node(index);
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cond_resched();
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}
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if (wq) {
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/*
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* Must be after io_uring_del_tctx_node() (removes nodes under
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* uring_lock) to avoid race with io_uring_try_cancel_iowq().
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*/
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io_wq_put_and_exit(wq);
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tctx->io_wq = NULL;
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}
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}
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void io_uring_unreg_ringfd(void)
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{
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struct io_uring_task *tctx = current->io_uring;
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int i;
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for (i = 0; i < IO_RINGFD_REG_MAX; i++) {
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if (tctx->registered_rings[i]) {
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fput(tctx->registered_rings[i]);
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tctx->registered_rings[i] = NULL;
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}
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}
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}
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static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd,
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int start, int end)
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{
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struct file *file;
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int offset;
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for (offset = start; offset < end; offset++) {
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offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
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if (tctx->registered_rings[offset])
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continue;
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file = fget(fd);
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if (!file) {
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return -EBADF;
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} else if (!io_is_uring_fops(file)) {
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fput(file);
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return -EOPNOTSUPP;
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}
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tctx->registered_rings[offset] = file;
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return offset;
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}
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return -EBUSY;
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}
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/*
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* Register a ring fd to avoid fdget/fdput for each io_uring_enter()
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* invocation. User passes in an array of struct io_uring_rsrc_update
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* with ->data set to the ring_fd, and ->offset given for the desired
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* index. If no index is desired, application may set ->offset == -1U
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* and we'll find an available index. Returns number of entries
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* successfully processed, or < 0 on error if none were processed.
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*/
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int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
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unsigned nr_args)
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{
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struct io_uring_rsrc_update __user *arg = __arg;
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struct io_uring_rsrc_update reg;
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struct io_uring_task *tctx;
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int ret, i;
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if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
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return -EINVAL;
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mutex_unlock(&ctx->uring_lock);
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ret = __io_uring_add_tctx_node(ctx, false);
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mutex_lock(&ctx->uring_lock);
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if (ret)
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return ret;
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tctx = current->io_uring;
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for (i = 0; i < nr_args; i++) {
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int start, end;
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if (copy_from_user(®, &arg[i], sizeof(reg))) {
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ret = -EFAULT;
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break;
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}
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if (reg.resv) {
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ret = -EINVAL;
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break;
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}
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if (reg.offset == -1U) {
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start = 0;
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end = IO_RINGFD_REG_MAX;
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} else {
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if (reg.offset >= IO_RINGFD_REG_MAX) {
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ret = -EINVAL;
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break;
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}
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start = reg.offset;
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end = start + 1;
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}
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ret = io_ring_add_registered_fd(tctx, reg.data, start, end);
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if (ret < 0)
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break;
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reg.offset = ret;
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if (copy_to_user(&arg[i], ®, sizeof(reg))) {
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fput(tctx->registered_rings[reg.offset]);
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tctx->registered_rings[reg.offset] = NULL;
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ret = -EFAULT;
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break;
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}
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}
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return i ? i : ret;
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}
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int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
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unsigned nr_args)
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{
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struct io_uring_rsrc_update __user *arg = __arg;
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struct io_uring_task *tctx = current->io_uring;
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struct io_uring_rsrc_update reg;
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int ret = 0, i;
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if (!nr_args || nr_args > IO_RINGFD_REG_MAX)
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return -EINVAL;
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if (!tctx)
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return 0;
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for (i = 0; i < nr_args; i++) {
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if (copy_from_user(®, &arg[i], sizeof(reg))) {
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ret = -EFAULT;
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break;
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}
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if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) {
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ret = -EINVAL;
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break;
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}
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reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX);
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if (tctx->registered_rings[reg.offset]) {
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fput(tctx->registered_rings[reg.offset]);
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tctx->registered_rings[reg.offset] = NULL;
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}
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}
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return i ? i : ret;
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}
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