io_uring: fix resource leak in io_import_dmabuf()

Replace the return statement with setting ret = -EINVAL and jumping to
the err label to ensure resources are released via io_release_dmabuf.

Fixes: a5c98e9 ("io_uring/zcrx: dmabuf backed zerocopy receive")
Signed-off-by: Penglei Jiang <superman.xpt@gmail.com>
Link: https://lore.kernel.org/r/20250625102703.68336-1-superman.xpt@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: superman-xpt

io_uring/zcrx.c

@@ -106,8 +106,10 @@ static int io_import_dmabuf(struct io_zcrx_ifq *ifq,
 	for_each_sgtable_dma_sg(mem->sgt, sg, i)
 		total_size += sg_dma_len(sg);
 
-	if (total_size < off + len)
-		return -EINVAL;
+	if (total_size < off + len) {
+		ret = -EINVAL;
+		goto err;
+	}
 
 	mem->dmabuf_offset = off;
 	mem->size = len;