From 639cd4343310327dd1435ae66ddbe8352e07dddc Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@google.com>
Date: Thu, 31 Aug 2023 13:44:33 +0000
Subject: [PATCH] Revert "Revert "ALSA: pcm: Use SG-buffer only when direct DMA
 is available""

This reverts commit 456a7a73404c135fbd8f28baa98c9141eeb3e58d which is
commit 7d50b295c4af16f814ee82369c4a234df5228801 upstream.

It breaks the Android abi.  If it is required in the future, it can
come back in an abi-safe way.

Bug: 161946584
Change-Id: I517a84f35ae5d791dc6ad9bcdbe3296b9e28c2bd
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
---
 sound/core/pcm_memory.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/sound/core/pcm_memory.c b/sound/core/pcm_memory.c
index d360655e5deb..22055bb2eba2 100644
--- a/sound/core/pcm_memory.c
+++ b/sound/core/pcm_memory.c
@@ -11,6 +11,7 @@
 #include <linux/moduleparam.h>
 #include <linux/vmalloc.h>
 #include <linux/export.h>
+#include <linux/dma-mapping.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/info.h>
@@ -65,6 +66,19 @@ static int do_alloc_pages(struct snd_card *card, int type, struct device *dev,
 	__update_allocated_size(card, size);
 	mutex_unlock(&card->memory_mutex);
 
+
+#ifdef CONFIG_SND_DMA_SGBUF
+	if ((type == SNDRV_DMA_TYPE_DEV_SG || type == SNDRV_DMA_TYPE_DEV_UC_SG) &&
+	    !dma_is_direct(get_dma_ops(dev))) {
+		/* mutate to continuous page allocation */
+		dev_dbg(dev, "Use continuous page allocator\n");
+		if (type == SNDRV_DMA_TYPE_DEV_SG)
+			type = SNDRV_DMA_TYPE_DEV;
+		else
+			type = SNDRV_DMA_TYPE_DEV_UC;
+	}
+#endif /* CONFIG_SND_DMA_SGBUF */
+
 	err = snd_dma_alloc_pages(type, dev, size, dmab);
 	if (!err) {
 		/* the actual allocation size might be bigger than requested,