[PATCH 09/10] io_uring: drop registered files and buffers at release time

[Jens Axboe <axboe@kernel.dk>]

Registered file and buffer tables are only torn down from
io_ring_ctx_free(), which only runs when all requests have completed and
the ctx refs have hit zero. Before this, every registered file remains
open.

The resource nodes are reference counted and any request using a
registered file or buffer holds its own reference to the node, so this
only releases what is actually unused. The rest follow as those requests
complete or get canceled.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 io_uring/io_uring.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index eb8a3626c684..977c8c510b85 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2196,8 +2196,6 @@ static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
 	io_sq_thread_finish(ctx);
 
 	mutex_lock(&ctx->uring_lock);
-	io_sqe_buffers_unregister(ctx);
-	io_sqe_files_unregister(ctx);
 	io_unregister_zcrx(ctx);
 	io_cqring_overflow_kill(ctx);
 	io_eventfd_unregister(ctx);
@@ -2463,6 +2461,9 @@ static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
 	xa_for_each(&ctx->personalities, index, creds)
 		io_unregister_personality(ctx, index);
 	io_terminate_zcrx(ctx);
+	/* Drop these now, rather than async, to unpin the files */
+	io_sqe_buffers_unregister(ctx);
+	io_sqe_files_unregister(ctx);
 	mutex_unlock(&ctx->uring_lock);
 
 	/*
-- 
2.55.0