linux-kernel - [PATCH] io_uring/rsrc: avoid NULL check in io_put_rsrc

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Message-ID: <20250216225900.1075446-1-csander@purestorage.com>
Date: Sun, 16 Feb 2025 15:58:59 -0700
From: Caleb Sander Mateos <csander@...estorage.com>
To: Jens Axboe <axboe@...nel.dk>,
	Pavel Begunkov <asml.silence@...il.com>
Cc: Caleb Sander Mateos <csander@...estorage.com>,
	io-uring@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] io_uring/rsrc: avoid NULL check in io_put_rsrc_node()

Most callers of io_put_rsrc_node() already check that node is non-NULL:
- io_rsrc_data_free()
- io_sqe_buffer_register()
- io_reset_rsrc_node()
- io_req_put_rsrc_nodes() (REQ_F_BUF_NODE indicates non-NULL buf_node)

Only io_splice_cleanup() can call io_put_rsrc_node() with a NULL node.
So move the NULL check there.

Signed-off-by: Caleb Sander Mateos <csander@...estorage.com>
---
 io_uring/rsrc.h   | 2 +-
 io_uring/splice.c | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 190f7ee45de9..a6d883c62b22 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -81,11 +81,11 @@ static inline struct io_rsrc_node *io_rsrc_node_lookup(struct io_rsrc_data *data
 }
 
 static inline void io_put_rsrc_node(struct io_ring_ctx *ctx, struct io_rsrc_node *node)
 {
 	lockdep_assert_held(&ctx->uring_lock);
-	if (node && !--node->refs)
+	if (!--node->refs)
 		io_free_rsrc_node(ctx, node);
 }
 
 static inline bool io_reset_rsrc_node(struct io_ring_ctx *ctx,
 				      struct io_rsrc_data *data, int index)
diff --git a/io_uring/splice.c b/io_uring/splice.c
index 5b84f1630611..7b89bd84d486 100644
--- a/io_uring/splice.c
+++ b/io_uring/splice.c
@@ -49,11 +49,12 @@ int io_tee_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 
 void io_splice_cleanup(struct io_kiocb *req)
 {
 	struct io_splice *sp = io_kiocb_to_cmd(req, struct io_splice);
 
-	io_put_rsrc_node(req->ctx, sp->rsrc_node);
+	if (sp->rsrc_node)
+		io_put_rsrc_node(req->ctx, sp->rsrc_node);
 }
 
 static struct file *io_splice_get_file(struct io_kiocb *req,
 				       unsigned int issue_flags)
 {
-- 
2.45.2