ALSA: memalloc: Drop special handling of GFP for CONTINUOUS allocation

Now that all users of snd_dma_continuous_data() is gone, let's drop
this ugly (and dangerous) way.

After this commit, SNDRV_DMA_TYPE_CONTINUOUS may take the standard
device pointer instead of the hacked pointer by the macro above, and
the memalloc core refers to the coherent_dma_mask of the given
device like other SNDRV_DMA_TYPE.  It's still allowed to pass NULL
there, and in that case, the allocation is performed always in the
normal zone.

For SNDRV_DMA_TYPE_VMALLOC, the device pointer is simply ignored.

Link: https://lore.kernel.org/r/20220823115740.14123-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/memalloc.h

@@ -26,9 +26,6 @@ struct snd_dma_device {
 	struct device *dev;		/* generic device */
 };
 
-#define snd_dma_continuous_data(x)	((struct device *)(__force unsigned long)(x))
-
-
 /*
  * buffer types
  */

sound/core/memalloc.c

@@ -18,25 +18,18 @@
 #include <sound/memalloc.h>
 #include "memalloc_local.h"
 
+#define DEFAULT_GFP \
+	(GFP_KERNEL | \
+	 __GFP_COMP |    /* compound page lets parts be mapped */ \
+	 __GFP_NORETRY | /* don't trigger OOM-killer */ \
+	 __GFP_NOWARN)   /* no stack trace print - this call is non-critical */
+
 static const struct snd_malloc_ops *snd_dma_get_ops(struct snd_dma_buffer *dmab);
 
 #ifdef CONFIG_SND_DMA_SGBUF
-static void *do_alloc_fallback_pages(struct device *dev, size_t size,
-				     dma_addr_t *addr, bool wc);
-static void do_free_fallback_pages(void *p, size_t size, bool wc);
 static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size);
 #endif
 
-/* a cast to gfp flag from the dev pointer; for CONTINUOUS and VMALLOC types */
-static inline gfp_t snd_mem_get_gfp_flags(const struct snd_dma_buffer *dmab,
-					  gfp_t default_gfp)
-{
-	if (!dmab->dev.dev)
-		return default_gfp;
-	else
-		return (__force gfp_t)(unsigned long)dmab->dev.dev;
-}
-
 static void *__snd_dma_alloc_pages(struct snd_dma_buffer *dmab, size_t size)
 {
 	const struct snd_malloc_ops *ops = snd_dma_get_ops(dmab);
@@ -284,24 +277,54 @@ EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
 /*
  * Continuous pages allocator
  */
-static void *do_alloc_pages(size_t size, dma_addr_t *addr, gfp_t gfp)
+static void *do_alloc_pages(struct device *dev, size_t size, dma_addr_t *addr,
+			    bool wc)
 {
-	void *p = alloc_pages_exact(size, gfp);
+	void *p;
+	gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
 
-	if (p)
+ again:
+	p = alloc_pages_exact(size, gfp);
+	if (!p)
+		return NULL;
 	*addr = page_to_phys(virt_to_page(p));
+	if (!dev)
+		return p;
+	if ((*addr + size - 1) & ~dev->coherent_dma_mask) {
+		if (IS_ENABLED(CONFIG_ZONE_DMA32) && !(gfp & GFP_DMA32)) {
+			gfp |= GFP_DMA32;
+			goto again;
+		}
+		if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
+			gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
+			goto again;
+		}
+	}
+#ifdef CONFIG_X86
+	if (wc)
+		set_memory_wc((unsigned long)(p), size >> PAGE_SHIFT);
+#endif
 	return p;
 }
 
+static void do_free_pages(void *p, size_t size, bool wc)
+{
+#ifdef CONFIG_X86
+	if (wc)
+		set_memory_wb((unsigned long)(p), size >> PAGE_SHIFT);
+#endif
+	free_pages_exact(p, size);
+}
+
+
 static void *snd_dma_continuous_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
-	return do_alloc_pages(size, &dmab->addr,
+	return do_alloc_pages(dmab->dev.dev, size, &dmab->addr, false);
-			      snd_mem_get_gfp_flags(dmab, GFP_KERNEL));
 }
 
 static void snd_dma_continuous_free(struct snd_dma_buffer *dmab)
 {
-	free_pages_exact(dmab->area, dmab->bytes);
+	do_free_pages(dmab->area, dmab->bytes, false);
 }
 
 static int snd_dma_continuous_mmap(struct snd_dma_buffer *dmab,
@@ -324,9 +347,7 @@ static const struct snd_malloc_ops snd_dma_continuous_ops = {
  */
 static void *snd_dma_vmalloc_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
-	gfp_t gfp = snd_mem_get_gfp_flags(dmab, GFP_KERNEL | __GFP_HIGHMEM);
+	return vmalloc(size);
-
-	return __vmalloc(size, gfp);
 }
 
 static void snd_dma_vmalloc_free(struct snd_dma_buffer *dmab)
@@ -440,12 +461,6 @@ static const struct snd_malloc_ops snd_dma_iram_ops = {
 };
 #endif /* CONFIG_GENERIC_ALLOCATOR */
 
-#define DEFAULT_GFP \
-	(GFP_KERNEL | \
-	 __GFP_COMP |    /* compound page lets parts be mapped */ \
-	 __GFP_NORETRY | /* don't trigger OOM-killer */ \
-	 __GFP_NOWARN)   /* no stack trace print - this call is non-critical */
-
 /*
  * Coherent device pages allocator
  */
@@ -479,12 +494,12 @@ static const struct snd_malloc_ops snd_dma_dev_ops = {
 #ifdef CONFIG_SND_DMA_SGBUF
 static void *snd_dma_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
-	return do_alloc_fallback_pages(dmab->dev.dev, size, &dmab->addr, true);
+	return do_alloc_pages(dmab->dev.dev, size, &dmab->addr, true);
 }
 
 static void snd_dma_wc_free(struct snd_dma_buffer *dmab)
 {
-	do_free_fallback_pages(dmab->area, dmab->bytes, true);
+	do_free_pages(dmab->area, dmab->bytes, true);
 }
 
 static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab,
@@ -697,37 +712,6 @@ static const struct snd_malloc_ops snd_dma_sg_wc_ops = {
 	.get_chunk_size = snd_dma_noncontig_get_chunk_size,
 };
 
-/* manual page allocations with wc setup */
-static void *do_alloc_fallback_pages(struct device *dev, size_t size,
-				     dma_addr_t *addr, bool wc)
-{
-	gfp_t gfp = GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN;
-	void *p;
-
- again:
-	p = do_alloc_pages(size, addr, gfp);
-	if (!p || (*addr + size - 1) & ~dev->coherent_dma_mask) {
-		if (IS_ENABLED(CONFIG_ZONE_DMA32) && !(gfp & GFP_DMA32)) {
-			gfp |= GFP_DMA32;
-			goto again;
-		}
-		if (IS_ENABLED(CONFIG_ZONE_DMA) && !(gfp & GFP_DMA)) {
-			gfp = (gfp & ~GFP_DMA32) | GFP_DMA;
-			goto again;
-		}
-	}
-	if (p && wc)
-		set_memory_wc((unsigned long)(p), size >> PAGE_SHIFT);
-	return p;
-}
-
-static void do_free_fallback_pages(void *p, size_t size, bool wc)
-{
-	if (wc)
-		set_memory_wb((unsigned long)(p), size >> PAGE_SHIFT);
-	free_pages_exact(p, size);
-}
-
 /* Fallback SG-buffer allocations for x86 */
 struct snd_dma_sg_fallback {
 	size_t count;
@@ -742,7 +726,7 @@ static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab,
 	size_t i;
 
 	for (i = 0; i < sgbuf->count && sgbuf->pages[i]; i++)
-		do_free_fallback_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc);
+		do_free_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc);
 	kvfree(sgbuf->pages);
 	kvfree(sgbuf->addrs);
 	kfree(sgbuf);
@@ -769,8 +753,7 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
 		goto error;
 
 	for (i = 0; i < count; sgbuf->count++, i++) {
-		p = do_alloc_fallback_pages(dmab->dev.dev, PAGE_SIZE,
+		p = do_alloc_pages(dmab->dev.dev, PAGE_SIZE, &sgbuf->addrs[i], wc);
-					    &sgbuf->addrs[i], wc);
 		if (!p)
 			goto error;
 		sgbuf->pages[i] = virt_to_page(p);