+ return io_task_match(req, task);
+}
+
+static bool __io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
+ struct task_struct *task,
+ struct files_struct *files)
+{
+ bool ret;
+
+ ret = io_uring_cancel_files(ctx, files);
+ if (!files) {
+ enum io_wq_cancel cret;
+
+ cret = io_wq_cancel_cb(ctx->io_wq, io_cancel_task_cb, task, true);
+ if (cret != IO_WQ_CANCEL_NOTFOUND)
+ ret = true;
+
+ /* SQPOLL thread does its own polling */
+ if (!(ctx->flags & IORING_SETUP_SQPOLL)) {
+ while (!list_empty_careful(&ctx->iopoll_list)) {
+ io_iopoll_try_reap_events(ctx);
+ ret = true;
+ }
+ }
+
+ ret |= io_poll_remove_all(ctx, task);
+ ret |= io_kill_timeouts(ctx, task);
+ }
+
+ return ret;
+}
+
+/*
+ * We need to iteratively cancel requests, in case a request has dependent
+ * hard links. These persist even for failure of cancelations, hence keep
+ * looping until none are found.
+ */
+static void io_uring_cancel_task_requests(struct io_ring_ctx *ctx,
+ struct files_struct *files)
+{
+ struct task_struct *task = current;
+
+ if ((ctx->flags & IORING_SETUP_SQPOLL) && ctx->sq_data)
+ task = ctx->sq_data->thread;
+
+ io_cqring_overflow_flush(ctx, true, task, files);
+
+ while (__io_uring_cancel_task_requests(ctx, task, files)) {
+ io_run_task_work();
+ cond_resched();
+ }
+}
+
+/*
+ * Note that this task has used io_uring. We use it for cancelation purposes.
+ */
+static int io_uring_add_task_file(struct file *file)
+{
+ struct io_uring_task *tctx = current->io_uring;
+
+ if (unlikely(!tctx)) {
+ int ret;
+
+ ret = io_uring_alloc_task_context(current);
+ if (unlikely(ret))
+ return ret;
+ tctx = current->io_uring;
+ }
+ if (tctx->last != file) {
+ void *old = xa_load(&tctx->xa, (unsigned long)file);
+
+ if (!old) {
+ get_file(file);
+ xa_store(&tctx->xa, (unsigned long)file, file, GFP_KERNEL);
+ }
+ tctx->last = file;
+ }
+
+ return 0;
+}
+
+/*
+ * Remove this io_uring_file -> task mapping.
+ */
+static void io_uring_del_task_file(struct file *file)
+{
+ struct io_uring_task *tctx = current->io_uring;
+
+ if (tctx->last == file)
+ tctx->last = NULL;
+ file = xa_erase(&tctx->xa, (unsigned long)file);
+ if (file)
+ fput(file);
+}
+
+static void __io_uring_attempt_task_drop(struct file *file)
+{
+ struct file *old = xa_load(¤t->io_uring->xa, (unsigned long)file);
+
+ if (old == file)
+ io_uring_del_task_file(file);
+}
+
+/*
+ * Drop task note for this file if we're the only ones that hold it after
+ * pending fput()
+ */
+static void io_uring_attempt_task_drop(struct file *file, bool exiting)
+{
+ if (!current->io_uring)
+ return;
+ /*
+ * fput() is pending, will be 2 if the only other ref is our potential
+ * task file note. If the task is exiting, drop regardless of count.
+ */
+ if (!exiting && atomic_long_read(&file->f_count) != 2)
+ return;
+
+ __io_uring_attempt_task_drop(file);
+}
+
+void __io_uring_files_cancel(struct files_struct *files)
+{
+ struct io_uring_task *tctx = current->io_uring;
+ struct file *file;
+ unsigned long index;
+
+ /* make sure overflow events are dropped */
+ tctx->in_idle = true;
+
+ xa_for_each(&tctx->xa, index, file) {
+ struct io_ring_ctx *ctx = file->private_data;
+
+ io_uring_cancel_task_requests(ctx, files);
+ if (files)
+ io_uring_del_task_file(file);
+ }
+}
+
+static inline bool io_uring_task_idle(struct io_uring_task *tctx)
+{
+ return atomic_long_read(&tctx->req_issue) ==
+ atomic_long_read(&tctx->req_complete);
+}
+
+/*
+ * Find any io_uring fd that this task has registered or done IO on, and cancel
+ * requests.
+ */
+void __io_uring_task_cancel(void)
+{
+ struct io_uring_task *tctx = current->io_uring;
+ DEFINE_WAIT(wait);
+ long completions;
+
+ /* make sure overflow events are dropped */
+ tctx->in_idle = true;
+
+ while (!io_uring_task_idle(tctx)) {
+ /* read completions before cancelations */
+ completions = atomic_long_read(&tctx->req_complete);
+ __io_uring_files_cancel(NULL);
+
+ prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
+
+ /*
+ * If we've seen completions, retry. This avoids a race where
+ * a completion comes in before we did prepare_to_wait().
+ */
+ if (completions != atomic_long_read(&tctx->req_complete))
+ continue;
+ if (io_uring_task_idle(tctx))
+ break;
+ schedule();
+ }
+
+ finish_wait(&tctx->wait, &wait);
+ tctx->in_idle = false;