s390/cio: fix a memleak in css_alloc_subchannel

When dma_set_coherent_mask() fails, sch->lock has not been
freed, which is allocated in css_sch_create_locks(), leading
to a memleak.

Fixes: 4520a91 ("s390/cio: use dma helpers for setting masks")
Signed-off-by: Dinghao Liu <dinghao.liu@zju.edu.cn>
Message-Id: <20230921071412.13806-1-dinghao.liu@zju.edu.cn>
Link: https://lore.kernel.org/linux-s390/bd38baa8-7b9d-4d89-9422-7e943d626d6e@linux.ibm.com/
Reviewed-by: Halil Pasic <pasic@linux.ibm.com>
Reviewed-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

drivers/s390/cio/css.c

@@ -233,17 +233,19 @@ struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
 	 */
 	ret = dma_set_coherent_mask(&sch->dev, DMA_BIT_MASK(31));
 	if (ret)
-		goto err;
+		goto err_lock;
 	/*
 	 * But we don't have such restrictions imposed on the stuff that
 	 * is handled by the streaming API.
 	 */
 	ret = dma_set_mask(&sch->dev, DMA_BIT_MASK(64));
 	if (ret)
-		goto err;
+		goto err_lock;
 
 	return sch;
 
+err_lock:
+	kfree(sch->lock);
 err:
 	kfree(sch);
 	return ERR_PTR(ret);