diff options
Diffstat (limited to 'io_uring/tctx.c')
| -rw-r--r-- | io_uring/tctx.c | 424 |
1 files changed, 424 insertions, 0 deletions
diff --git a/io_uring/tctx.c b/io_uring/tctx.c new file mode 100644 index 000000000..466b7300e --- /dev/null +++ b/io_uring/tctx.c @@ -0,0 +1,424 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/file.h> +#include <linux/mm.h> +#include <linux/slab.h> +#include <linux/nospec.h> +#include <linux/io_uring.h> + +#include <uapi/linux/io_uring.h> + +#include "io_uring.h" +#include "tctx.h" +#include "bpf_filter.h" + +static struct io_wq *io_init_wq_offload(struct io_ring_ctx *ctx, + struct task_struct *task) +{ + struct io_wq_hash *hash; + struct io_wq_data data; + unsigned int concurrency; + + mutex_lock(&ctx->uring_lock); + hash = ctx->hash_map; + if (!hash) { + hash = kzalloc_obj(*hash); + if (!hash) { + mutex_unlock(&ctx->uring_lock); + return ERR_PTR(-ENOMEM); + } + refcount_set(&hash->refs, 1); + init_waitqueue_head(&hash->wait); + ctx->hash_map = hash; + } + mutex_unlock(&ctx->uring_lock); + + data.hash = hash; + data.task = task; + + /* Do QD, or 4 * CPUS, whatever is smallest */ + concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); + + return io_wq_create(concurrency, &data); +} + +void io_uring_free_tctx(struct task_struct *tsk) +{ + struct io_uring_task *tctx = tsk->io_uring; + struct io_tctx_node *node; + unsigned long index; + + /* + * Fault injection forcing allocation errors in the xa_store() path + * can lead to xa_empty() returning false, even though no actual + * node is stored in the xarray. Until that gets sorted out, attempt + * an iteration here and warn if any entries are found. + */ + if (tctx) { + xa_for_each(&tctx->xa, index, node) { + WARN_ON_ONCE(1); + break; + } + WARN_ON_ONCE(tctx->io_wq); + WARN_ON_ONCE(tctx->cached_refs); + + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + tsk->io_uring = NULL; + } +} + +void __io_uring_free(struct task_struct *tsk) +{ + io_uring_free_tctx(tsk); + if (tsk->io_uring_restrict) { + io_put_bpf_filters(tsk->io_uring_restrict); + kfree(tsk->io_uring_restrict); + tsk->io_uring_restrict = NULL; + } +} + +__cold struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task, + struct io_ring_ctx *ctx) +{ + struct io_uring_task *tctx; + int ret; + + tctx = kzalloc_obj(*tctx); + if (unlikely(!tctx)) + return ERR_PTR(-ENOMEM); + + ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL); + if (unlikely(ret)) { + kfree(tctx); + return ERR_PTR(ret); + } + + tctx->io_wq = io_init_wq_offload(ctx, task); + if (IS_ERR(tctx->io_wq)) { + ret = PTR_ERR(tctx->io_wq); + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + return ERR_PTR(ret); + } + + tctx->task = task; + xa_init(&tctx->xa); + init_waitqueue_head(&tctx->wait); + atomic_set(&tctx->in_cancel, 0); + atomic_set(&tctx->inflight_tracked, 0); + mpscq_init(&tctx->task_list, &tctx->task_head); + INIT_WORK(&tctx->fallback_work, io_tctx_fallback_work); + init_task_work(&tctx->task_work, tctx_task_work); + return tctx; +} + +static int io_tctx_install_node(struct io_ring_ctx *ctx, + struct io_uring_task *tctx) +{ + struct io_tctx_node *node; + int ret; + + if (xa_load(&tctx->xa, (unsigned long)ctx)) + return 0; + + node = kmalloc_obj(*node); + if (!node) + return -ENOMEM; + node->ctx = ctx; + node->task = current; + + ret = xa_err(xa_store(&tctx->xa, (unsigned long)ctx, + node, GFP_KERNEL)); + if (ret) { + kfree(node); + return ret; + } + + mutex_lock(&ctx->tctx_lock); + list_add(&node->ctx_node, &ctx->tctx_list); + mutex_unlock(&ctx->tctx_lock); + return 0; +} + +int __io_uring_add_tctx_node(struct io_ring_ctx *ctx) +{ + struct io_uring_task *tctx = current->io_uring; + bool new_tctx = false; + int ret; + + if (unlikely(!tctx)) { + tctx = io_uring_alloc_task_context(current, ctx); + if (IS_ERR(tctx)) + return PTR_ERR(tctx); + new_tctx = true; + + if (data_race(ctx->int_flags) & IO_RING_F_IOWQ_LIMITS_SET) { + unsigned int limits[2]; + + mutex_lock(&ctx->uring_lock); + limits[0] = ctx->iowq_limits[0]; + limits[1] = ctx->iowq_limits[1]; + mutex_unlock(&ctx->uring_lock); + + ret = io_wq_max_workers(tctx->io_wq, limits); + if (ret) + goto err_free; + } + } + + /* + * Re-activate io-wq keepalive on any new io_uring usage. The wq may have + * been marked for idle-exit when the task temporarily had no active + * io_uring instances. + */ + if (tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, false); + + if (new_tctx) + current->io_uring = tctx; + + ret = io_tctx_install_node(ctx, tctx); + if (!ret) + return 0; +err_free: + if (new_tctx) { + current->io_uring = NULL; + if (tctx->io_wq) { + io_wq_exit_start(tctx->io_wq); + io_wq_put_and_exit(tctx->io_wq); + } + percpu_counter_destroy(&tctx->inflight); + kfree(tctx); + } + return ret; +} + +int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx) +{ + int ret; + + if (ctx->flags & IORING_SETUP_SINGLE_ISSUER + && ctx->submitter_task != current) + return -EEXIST; + + ret = __io_uring_add_tctx_node(ctx); + if (ret) + return ret; + + current->io_uring->last = ctx; + return 0; +} + +/* + * Remove this io_uring_file -> task mapping. + */ +__cold void io_uring_del_tctx_node(unsigned long index) +{ + struct io_uring_task *tctx = current->io_uring; + struct io_tctx_node *node; + + if (!tctx) + return; + node = xa_erase(&tctx->xa, index); + if (!node) + return; + + WARN_ON_ONCE(current != node->task); + WARN_ON_ONCE(list_empty(&node->ctx_node)); + + mutex_lock(&node->ctx->tctx_lock); + list_del(&node->ctx_node); + mutex_unlock(&node->ctx->tctx_lock); + + if (tctx->last == node->ctx) + tctx->last = NULL; + kfree(node); + + if (xa_empty(&tctx->xa) && tctx->io_wq) + io_wq_set_exit_on_idle(tctx->io_wq, true); +} + +__cold void io_uring_clean_tctx(struct io_uring_task *tctx) +{ + struct io_wq *wq = tctx->io_wq; + struct io_tctx_node *node; + unsigned long index; + + xa_for_each(&tctx->xa, index, node) { + io_uring_del_tctx_node(index); + cond_resched(); + } + if (wq) { + /* + * Must be after io_uring_del_tctx_node() (removes nodes under + * uring_lock) to avoid race with io_uring_try_cancel_iowq(). + */ + io_wq_put_and_exit(wq); + tctx->io_wq = NULL; + } +} + +void io_uring_unreg_ringfd(void) +{ + struct io_uring_task *tctx = current->io_uring; + int i; + + for (i = 0; i < IO_RINGFD_REG_MAX; i++) { + if (tctx->registered_rings[i]) { + fput(tctx->registered_rings[i]); + tctx->registered_rings[i] = NULL; + } + } +} + +int io_ring_add_registered_file(struct io_uring_task *tctx, struct file *file, + int start, int end) +{ + int offset, idx; + for (offset = start; offset < end; offset++) { + idx = array_index_nospec(offset, IO_RINGFD_REG_MAX); + if (tctx->registered_rings[idx]) + continue; + + tctx->registered_rings[idx] = file; + return idx; + } + return -EBUSY; +} + +static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd, + int start, int end) +{ + struct file *file; + int offset; + + file = fget(fd); + if (!file) { + return -EBADF; + } else if (!io_is_uring_fops(file)) { + fput(file); + return -EOPNOTSUPP; + } + offset = io_ring_add_registered_file(tctx, file, start, end); + if (offset < 0) + fput(file); + return offset; +} + +/* + * Register a ring fd to avoid fdget/fdput for each io_uring_enter() + * invocation. User passes in an array of struct io_uring_rsrc_update + * with ->data set to the ring_fd, and ->offset given for the desired + * index. If no index is desired, application may set ->offset == -1U + * and we'll find an available index. Returns number of entries + * successfully processed, or < 0 on error if none were processed. + */ +int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args) +{ + struct io_uring_rsrc_update __user *arg = __arg; + struct io_uring_rsrc_update reg; + struct io_uring_task *tctx; + int ret, i; + + if (!nr_args || nr_args > IO_RINGFD_REG_MAX) + return -EINVAL; + + mutex_unlock(&ctx->uring_lock); + ret = __io_uring_add_tctx_node(ctx); + mutex_lock(&ctx->uring_lock); + if (ret) + return ret; + + tctx = current->io_uring; + for (i = 0; i < nr_args; i++) { + int start, end; + + if (copy_from_user(®, &arg[i], sizeof(reg))) { + ret = -EFAULT; + break; + } + + if (reg.resv) { + ret = -EINVAL; + break; + } + + if (reg.offset == -1U) { + start = 0; + end = IO_RINGFD_REG_MAX; + } else { + if (reg.offset >= IO_RINGFD_REG_MAX) { + ret = -EINVAL; + break; + } + start = reg.offset; + end = start + 1; + } + + ret = io_ring_add_registered_fd(tctx, reg.data, start, end); + if (ret < 0) + break; + + reg.offset = ret; + if (copy_to_user(&arg[i], ®, sizeof(reg))) { + fput(tctx->registered_rings[reg.offset]); + tctx->registered_rings[reg.offset] = NULL; + ret = -EFAULT; + break; + } + } + + return i ? i : ret; +} + +int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg, + unsigned nr_args) +{ + struct io_uring_rsrc_update __user *arg = __arg; + struct io_uring_task *tctx = current->io_uring; + struct io_uring_rsrc_update reg; + int ret = 0, i; + + if (!nr_args || nr_args > IO_RINGFD_REG_MAX) + return -EINVAL; + if (!tctx) + return 0; + + for (i = 0; i < nr_args; i++) { + if (copy_from_user(®, &arg[i], sizeof(reg))) { + ret = -EFAULT; + break; + } + if (reg.resv || reg.data || reg.offset >= IO_RINGFD_REG_MAX) { + ret = -EINVAL; + break; + } + + reg.offset = array_index_nospec(reg.offset, IO_RINGFD_REG_MAX); + if (tctx->registered_rings[reg.offset]) { + fput(tctx->registered_rings[reg.offset]); + tctx->registered_rings[reg.offset] = NULL; + } + } + + return i ? i : ret; +} + +int __io_uring_fork(struct task_struct *tsk) +{ + struct io_restriction *res, *src = tsk->io_uring_restrict; + + /* Don't leave it dangling on error */ + tsk->io_uring_restrict = NULL; + + res = kzalloc_obj(*res, GFP_KERNEL_ACCOUNT); + if (!res) + return -ENOMEM; + + tsk->io_uring_restrict = res; + io_restriction_clone(res, src); + return 0; +} |