ARM: 9480/1: entry: expand comment in __switch_tografted

As per discussion between the developers in the mail thread
linked, expand the comment in __switch_to so that readers
of the code understand what is going on.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

1 files changed, 33 insertions, 0 deletions

diff --git a/io_uring/tctx.h b/io_uring/tctx.h
new file mode 100644
index 000000000..2310d2a0c
--- /dev/null
+++ b/io_uring/tctx.h
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+struct io_tctx_node {
+	struct list_head	ctx_node;
+	struct task_struct	*task;
+	struct io_ring_ctx	*ctx;
+};
+
+struct io_uring_task *io_uring_alloc_task_context(struct task_struct *task,
+						  struct io_ring_ctx *ctx);
+void io_uring_del_tctx_node(unsigned long index);
+int __io_uring_add_tctx_node(struct io_ring_ctx *ctx);
+int __io_uring_add_tctx_node_from_submit(struct io_ring_ctx *ctx);
+void io_uring_clean_tctx(struct io_uring_task *tctx);
+
+void io_uring_unreg_ringfd(void);
+int io_ringfd_register(struct io_ring_ctx *ctx, void __user *__arg,
+		       unsigned nr_args);
+int io_ringfd_unregister(struct io_ring_ctx *ctx, void __user *__arg,
+			 unsigned nr_args);
+
+/*
+ * Note that this task has used io_uring. We use it for cancelation purposes.
+ */
+static inline int io_uring_add_tctx_node(struct io_ring_ctx *ctx)
+{
+	struct io_uring_task *tctx = current->io_uring;
+
+	if (likely(tctx && tctx->last == ctx))
+		return 0;
+
+	return __io_uring_add_tctx_node_from_submit(ctx);
+}