Revert "ALSA: memalloc: Workaround for Xen PV"

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index f901504b5afc..81025f50a542 100644
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -541,15 +541,16 @@  static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
 	struct sg_table *sgt;
 	void *p;
 
-#ifdef CONFIG_SND_DMA_SGBUF
-	if (cpu_feature_enabled(X86_FEATURE_XENPV))
-		return snd_dma_sg_fallback_alloc(dmab, size);
-#endif
 	sgt = dma_alloc_noncontiguous(dmab->dev.dev, size, dmab->dev.dir,
 				      DEFAULT_GFP, 0);
 #ifdef CONFIG_SND_DMA_SGBUF
-	if (!sgt && !get_dma_ops(dmab->dev.dev))
+	if (!sgt && !get_dma_ops(dmab->dev.dev)) {
+		if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
+			dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
+		else
+			dmab->dev.type = SNDRV_DMA_TYPE_DEV_SG_FALLBACK;
 		return snd_dma_sg_fallback_alloc(dmab, size);
+	}
 #endif
 	if (!sgt)
 		return NULL;
@@ -716,38 +717,19 @@  static const struct snd_malloc_ops snd_dma_sg_wc_ops = {
 
 /* Fallback SG-buffer allocations for x86 */
 struct snd_dma_sg_fallback {
-	bool use_dma_alloc_coherent;
 	size_t count;
 	struct page **pages;
-	/* DMA address array; the first page contains #pages in ~PAGE_MASK */
-	dma_addr_t *addrs;
 };
 
 static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab,
 				       struct snd_dma_sg_fallback *sgbuf)
 {
-	size_t i, size;
-
-	if (sgbuf->pages && sgbuf->addrs) {
-		i = 0;
-		while (i < sgbuf->count) {
-			if (!sgbuf->pages[i] || !sgbuf->addrs[i])
-				break;
-			size = sgbuf->addrs[i] & ~PAGE_MASK;
-			if (WARN_ON(!size))
-				break;
-			if (sgbuf->use_dma_alloc_coherent)
-				dma_free_coherent(dmab->dev.dev, size << PAGE_SHIFT,
-						  page_address(sgbuf->pages[i]),
-						  sgbuf->addrs[i] & PAGE_MASK);
-			else
-				do_free_pages(page_address(sgbuf->pages[i]),
-					      size << PAGE_SHIFT, false);
-			i += size;
-		}
-	}
+	bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
+	size_t i;
+
+	for (i = 0; i < sgbuf->count && sgbuf->pages[i]; i++)
+		do_free_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc);
 	kvfree(sgbuf->pages);
-	kvfree(sgbuf->addrs);
 	kfree(sgbuf);
 }
 
@@ -756,36 +738,24 @@  static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
 	struct snd_dma_sg_fallback *sgbuf;
 	struct page **pagep, *curp;
 	size_t chunk, npages;
-	dma_addr_t *addrp;
 	dma_addr_t addr;
 	void *p;
-
-	/* correct the type */
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_SG)
-		dmab->dev.type = SNDRV_DMA_TYPE_DEV_SG_FALLBACK;
-	else if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
-		dmab->dev.type = SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
+	bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;
 
 	sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
 	if (!sgbuf)
 		return NULL;
-	sgbuf->use_dma_alloc_coherent = cpu_feature_enabled(X86_FEATURE_XENPV);
 	size = PAGE_ALIGN(size);
 	sgbuf->count = size >> PAGE_SHIFT;
 	sgbuf->pages = kvcalloc(sgbuf->count, sizeof(*sgbuf->pages), GFP_KERNEL);
-	sgbuf->addrs = kvcalloc(sgbuf->count, sizeof(*sgbuf->addrs), GFP_KERNEL);
-	if (!sgbuf->pages || !sgbuf->addrs)
+	if (!sgbuf->pages)
 		goto error;
 
 	pagep = sgbuf->pages;
-	addrp = sgbuf->addrs;
-	chunk = (PAGE_SIZE - 1) << PAGE_SHIFT; /* to fit in low bits in addrs */
+	chunk = size;
 	while (size > 0) {
 		chunk = min(size, chunk);
-		if (sgbuf->use_dma_alloc_coherent)
-			p = dma_alloc_coherent(dmab->dev.dev, chunk, &addr, DEFAULT_GFP);
-		else
-			p = do_alloc_pages(dmab->dev.dev, chunk, &addr, false);
+		p = do_alloc_pages(dmab->dev.dev, chunk, &addr, wc);
 		if (!p) {
 			if (chunk <= PAGE_SIZE)
 				goto error;
@@ -797,25 +767,17 @@  static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
 		size -= chunk;
 		/* fill pages */
 		npages = chunk >> PAGE_SHIFT;
-		*addrp = npages; /* store in lower bits */
 		curp = virt_to_page(p);
-		while (npages--) {
+		while (npages--)
 			*pagep++ = curp++;
-			*addrp++ |= addr;
-			addr += PAGE_SIZE;
-		}
 	}
 
 	p = vmap(sgbuf->pages, sgbuf->count, VM_MAP, PAGE_KERNEL);
 	if (!p)
 		goto error;
-
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
-		set_pages_array_wc(sgbuf->pages, sgbuf->count);
-
 	dmab->private_data = sgbuf;
 	/* store the first page address for convenience */
-	dmab->addr = sgbuf->addrs[0] & PAGE_MASK;
+	dmab->addr = snd_sgbuf_get_addr(dmab, 0);
 	return p;
 
  error:
@@ -825,23 +787,10 @@  static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
 
 static void snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab)
 {
-	struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
-
-	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)
-		set_pages_array_wb(sgbuf->pages, sgbuf->count);
 	vunmap(dmab->area);
 	__snd_dma_sg_fallback_free(dmab, dmab->private_data);
 }
 
-static dma_addr_t snd_dma_sg_fallback_get_addr(struct snd_dma_buffer *dmab,
-					       size_t offset)
-{
-	struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
-	size_t index = offset >> PAGE_SHIFT;
-
-	return (sgbuf->addrs[index] & PAGE_MASK) | (offset & ~PAGE_MASK);
-}
-
 static int snd_dma_sg_fallback_mmap(struct snd_dma_buffer *dmab,
 				    struct vm_area_struct *area)
 {
@@ -856,8 +805,8 @@  static const struct snd_malloc_ops snd_dma_sg_fallback_ops = {
 	.alloc = snd_dma_sg_fallback_alloc,
 	.free = snd_dma_sg_fallback_free,
 	.mmap = snd_dma_sg_fallback_mmap,
-	.get_addr = snd_dma_sg_fallback_get_addr,
 	/* reuse vmalloc helpers */
+	.get_addr = snd_dma_vmalloc_get_addr,
 	.get_page = snd_dma_vmalloc_get_page,
 	.get_chunk_size = snd_dma_vmalloc_get_chunk_size,
 };