summaryrefslogtreecommitdiff
path: root/io_uring/tctx.c
diff options
context:
space:
mode:
authorJens Axboe <axboe@kernel.dk>2022-05-25 11:01:04 -0600
committerJens Axboe <axboe@kernel.dk>2022-07-24 18:39:12 -0600
commitc9f06aa7de153cdbe424e7e38be39f2272cf78bc (patch)
treecd88c2b482d95378da7ed99ce691c722c37d8388 /io_uring/tctx.c
parenta4ad4f748ea96202451f88b6385d7283d0f2e513 (diff)
io_uring: move io_uring_task (tctx) helpers into its own file
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring/tctx.c')
-rw-r--r--io_uring/tctx.c332
1 files changed, 332 insertions, 0 deletions
diff --git a/io_uring/tctx.c b/io_uring/tctx.c
new file mode 100644
index 000000000000..3f7e9feb6ca2
--- /dev/null
+++ b/io_uring/tctx.c
@@ -0,0 +1,332 @@
+// 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_types.h"
+#include "io_uring.h"
+#include "tctx.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(sizeof(*hash), GFP_KERNEL);
+ 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;
+ data.free_work = io_wq_free_work;
+ data.do_work = io_wq_submit_work;
+
+ /* 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(struct task_struct *tsk)
+{
+ struct io_uring_task *tctx = tsk->io_uring;
+
+ WARN_ON_ONCE(!xa_empty(&tctx->xa));
+ WARN_ON_ONCE(tctx->io_wq);
+ WARN_ON_ONCE(tctx->cached_refs);
+
+ kfree(tctx->registered_rings);
+ percpu_counter_destroy(&tctx->inflight);
+ kfree(tctx);
+ tsk->io_uring = NULL;
+}
+
+__cold int io_uring_alloc_task_context(struct task_struct *task,
+ struct io_ring_ctx *ctx)
+{
+ struct io_uring_task *tctx;
+ int ret;
+
+ tctx = kzalloc(sizeof(*tctx), GFP_KERNEL);
+ if (unlikely(!tctx))
+ return -ENOMEM;
+
+ tctx->registered_rings = kcalloc(IO_RINGFD_REG_MAX,
+ sizeof(struct file *), GFP_KERNEL);
+ if (unlikely(!tctx->registered_rings)) {
+ kfree(tctx);
+ return -ENOMEM;
+ }
+
+ ret = percpu_counter_init(&tctx->inflight, 0, GFP_KERNEL);
+ if (unlikely(ret)) {
+ kfree(tctx->registered_rings);
+ kfree(tctx);
+ return 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->registered_rings);
+ kfree(tctx);
+ return ret;
+ }
+
+ xa_init(&tctx->xa);
+ init_waitqueue_head(&tctx->wait);
+ atomic_set(&tctx->in_idle, 0);
+ atomic_set(&tctx->inflight_tracked, 0);
+ task->io_uring = tctx;
+ spin_lock_init(&tctx->task_lock);
+ INIT_WQ_LIST(&tctx->task_list);
+ INIT_WQ_LIST(&tctx->prio_task_list);
+ init_task_work(&tctx->task_work, tctx_task_work);
+ return 0;
+}
+
+int __io_uring_add_tctx_node(struct io_ring_ctx *ctx)
+{
+ struct io_uring_task *tctx = current->io_uring;
+ struct io_tctx_node *node;
+ int ret;
+
+ if (unlikely(!tctx)) {
+ ret = io_uring_alloc_task_context(current, ctx);
+ if (unlikely(ret))
+ return ret;
+
+ tctx = current->io_uring;
+ if (ctx->iowq_limits_set) {
+ unsigned int limits[2] = { ctx->iowq_limits[0],
+ ctx->iowq_limits[1], };
+
+ ret = io_wq_max_workers(tctx->io_wq, limits);
+ if (ret)
+ return ret;
+ }
+ }
+ if (!xa_load(&tctx->xa, (unsigned long)ctx)) {
+ node = kmalloc(sizeof(*node), GFP_KERNEL);
+ 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->uring_lock);
+ list_add(&node->ctx_node, &ctx->tctx_list);
+ mutex_unlock(&ctx->uring_lock);
+ }
+ tctx->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->uring_lock);
+ list_del(&node->ctx_node);
+ mutex_unlock(&node->ctx->uring_lock);
+
+ if (tctx->last == node->ctx)
+ tctx->last = NULL;
+ kfree(node);
+}
+
+__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;
+ }
+ }
+}
+
+static int io_ring_add_registered_fd(struct io_uring_task *tctx, int fd,
+ int start, int end)
+{
+ struct file *file;
+ int offset;
+
+ for (offset = start; offset < end; offset++) {
+ offset = array_index_nospec(offset, IO_RINGFD_REG_MAX);
+ if (tctx->registered_rings[offset])
+ continue;
+
+ file = fget(fd);
+ if (!file) {
+ return -EBADF;
+ } else if (!io_is_uring_fops(file)) {
+ fput(file);
+ return -EOPNOTSUPP;
+ }
+ tctx->registered_rings[offset] = file;
+ return offset;
+ }
+
+ return -EBUSY;
+}
+
+/*
+ * 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(&reg, &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], &reg, 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(&reg, &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;
+}