io_uring/rsrc: use io_cache_free() to free node

Replace kfree(node) with io_cache_free() in io_buffer_register_bvec()
to match all other error paths that free nodes allocated via
io_rsrc_node_alloc(). The node is allocated through io_cache_alloc()
internally, so it should be returned to the cache via io_cache_free()
for proper object reuse.

Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
Link: https://patch.msgid.link/20260331104509.7055-1-liu.yun@linux.dev
[axboe: remove fixes tag, it's not a fix, it's a cleanup]
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: JackieLiu1

io_uring/rsrc.c

@@ -961,7 +961,7 @@ int io_buffer_register_bvec(struct io_uring_cmd *cmd, struct request *rq,
 	 */
 	imu = io_alloc_imu(ctx, blk_rq_nr_phys_segments(rq));
 	if (!imu) {
-		kfree(node);
+		io_cache_free(&ctx->node_cache, node);
 		ret = -ENOMEM;
 		goto unlock;
 	}