[PATCH v2] ALSA: hda/core: add cleanup in snd_hdac_bus_alloc_stream_pages()

[Zhao Dongdong]

From: Zhao Dongdong <zhaodongdong@xxxxxxxxxx>

The current error handling in snd_hdac_bus_alloc_stream_pages()
returns directly on failure without cleaning up already allocated
resources. While callers are supposed to release those via
snd_hdac_bus_free_stream_pages() at destructor, adding explicit
cleanup makes the function more self-contained and safer against
future misuse.

Add proper error cleanup path using goto labels to free previously
allocated BDL DMA buffers, position buffer, and ring buffer in
reverse allocation order.

Signed-off-by: Zhao Dongdong <zhaodongdong@xxxxxxxxxx>
---
v2: Update subject and description.
v1: https://lore.kernel.org/all/87pl108lp1.wl-tiwai@xxxxxxx/
---
 sound/hda/core/controller.c | 18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/sound/hda/core/controller.c b/sound/hda/core/controller.c
index 69e11d62bbfa..5d8731447ef6 100644
--- a/sound/hda/core/controller.c
+++ b/sound/hda/core/controller.c
@@ -713,7 +713,7 @@ int snd_hdac_bus_alloc_stream_pages(struct hdac_bus *bus)
 					  BDL_SIZE, &s->bdl);
 		num_streams++;
 		if (err < 0)
-			return -ENOMEM;
+			goto error_bdl;
 	}
 
 	if (WARN_ON(!num_streams))
@@ -722,12 +722,24 @@ int snd_hdac_bus_alloc_stream_pages(struct hdac_bus *bus)
 	err = snd_dma_alloc_pages(dma_type, bus->dev,
 				  num_streams * 8, &bus->posbuf);
 	if (err < 0)
-		return -ENOMEM;
+		goto error_bdl;
 	list_for_each_entry(s, &bus->stream_list, list)
 		s->posbuf = (__le32 *)(bus->posbuf.area + s->index * 8);
 
 	/* single page (at least 4096 bytes) must suffice for both ringbuffes */
-	return snd_dma_alloc_pages(dma_type, bus->dev, PAGE_SIZE, &bus->rb);
+	err = snd_dma_alloc_pages(dma_type, bus->dev, PAGE_SIZE, &bus->rb);
+	if (err < 0)
+		goto error_posbuf;
+	return 0;
+
+error_posbuf:
+	snd_dma_free_pages(&bus->posbuf);
+error_bdl:
+	list_for_each_entry(s, &bus->stream_list, list) {
+		if (s->bdl.area)
+			snd_dma_free_pages(&s->bdl);
+	}
+	return -ENOMEM;
 }
 EXPORT_SYMBOL_GPL(snd_hdac_bus_alloc_stream_pages);
 
-- 
2.25.1