From: Keith Busch <kbusch@kernel.org>

When a registered resource is about to be freed, check if it has
registered a release function, and call it if so. This is preparing for
resources that are related to an external component.

Signed-off-by: Keith Busch <kbusch@kernel.org>
---
  io_uring/rsrc.c | 2 ++
  io_uring/rsrc.h | 3 +++
  2 files changed, 5 insertions(+)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index 4d0e1c06c8bc6..30f08cf13ef60 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c

@@ -455,6 +455,8 @@ void io_free_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
  	case IORING_RSRC_BUFFER:
  		if (node->buf)
  			io_buffer_unmap(ctx, node);
+		if (node->release)
+			node->release(node->priv);
  		break;
  	default:
  		WARN_ON_ONCE(1);

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index abd0d5d42c3e1..a3826ab84e666 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h

@@ -24,6 +24,9 @@ struct io_rsrc_node {
  		unsigned long file_ptr;
  		struct io_mapped_ubuf *buf;
  	};
+
+	void (*release)(void *);
+	void *priv;