ALSA: core: Abstract memory alloc helpers

This patch introduces the ops table to each memory allocation type
(SNDRV_DMA_TYPE_XXX) and abstract the handling for the better code
management.  Then we get separate the page allocation, release and
other tasks for each type, especially for the SG buffer.

Each buffer type has now callbacks in the struct snd_malloc_ops, and
the common helper functions call those ops accordingly.  The former
inline code that is specific to SG-buffer is moved into the local
sgbuf.c, and we can simplify the PCM code without details of memory
handling.

Link: https://lore.kernel.org/r/20210609162551.7842-4-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 59 insertions, 31 deletions

diff --git a/sound/core/sgbuf.c b/sound/core/sgbuf.c
index 29ddb76187e5..232cf3f1bcb3 100644
--- a/sound/core/sgbuf.c
+++ b/sound/core/sgbuf.c
@@ -10,20 +10,34 @@
 #include <linux/vmalloc.h>
 #include <linux/export.h>
 #include <sound/memalloc.h>
-
+#include "memalloc_local.h"
+
+struct snd_sg_page {
+	void *buf;
+	dma_addr_t addr;
+};
+
+struct snd_sg_buf {
+	int size;	/* allocated byte size */
+	int pages;	/* allocated pages */
+	int tblsize;	/* allocated table size */
+	struct snd_sg_page *table;	/* address table */
+	struct page **page_table;	/* page table (for vmap/vunmap) */
+	struct device *dev;
+};
 
 /* table entries are align to 32 */
 #define SGBUF_TBL_ALIGN		32
 #define sgbuf_align_table(tbl)	ALIGN((tbl), SGBUF_TBL_ALIGN)
 
-int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
+static void snd_dma_sg_free(struct snd_dma_buffer *dmab)
 {
 	struct snd_sg_buf *sgbuf = dmab->private_data;
 	struct snd_dma_buffer tmpb;
 	int i;
 
-	if (! sgbuf)
-		return -EINVAL;
+	if (!sgbuf)
+		return;
 
 	vunmap(dmab->area);
 	dmab->area = NULL;
@@ -45,15 +59,11 @@ int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab)
 	kfree(sgbuf->page_table);
 	kfree(sgbuf);
 	dmab->private_data = NULL;
-	
-	return 0;
 }
 
 #define MAX_ALLOC_PAGES		32
 
-void *snd_malloc_sgbuf_pages(struct device *device,
-			     size_t size, struct snd_dma_buffer *dmab,
-			     size_t *res_size)
+static int snd_dma_sg_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
 	struct snd_sg_buf *sgbuf;
 	unsigned int i, pages, chunk, maxpages;
@@ -63,18 +73,16 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 	int type = SNDRV_DMA_TYPE_DEV;
 	pgprot_t prot = PAGE_KERNEL;
 
-	dmab->area = NULL;
-	dmab->addr = 0;
 	dmab->private_data = sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
-	if (! sgbuf)
-		return NULL;
+	if (!sgbuf)
+		return -ENOMEM;
 	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_UC_SG) {
 		type = SNDRV_DMA_TYPE_DEV_UC;
 #ifdef pgprot_noncached
 		prot = pgprot_noncached(PAGE_KERNEL);
 #endif
 	}
-	sgbuf->dev = device;
+	sgbuf->dev = dmab->dev.dev;
 	pages = snd_sgbuf_aligned_pages(size);
 	sgbuf->tblsize = sgbuf_align_table(pages);
 	table = kcalloc(sgbuf->tblsize, sizeof(*table), GFP_KERNEL);
@@ -94,12 +102,10 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 		if (chunk > maxpages)
 			chunk = maxpages;
 		chunk <<= PAGE_SHIFT;
-		if (snd_dma_alloc_pages_fallback(type, device,
+		if (snd_dma_alloc_pages_fallback(type, dmab->dev.dev,
 						 chunk, &tmpb) < 0) {
 			if (!sgbuf->pages)
 				goto _failed;
-			if (!res_size)
-				goto _failed;
 			size = sgbuf->pages * PAGE_SIZE;
 			break;
 		}
@@ -124,27 +130,42 @@ void *snd_malloc_sgbuf_pages(struct device *device,
 	dmab->area = vmap(sgbuf->page_table, sgbuf->pages, VM_MAP, prot);
 	if (! dmab->area)
 		goto _failed;
-	if (res_size)
-		*res_size = sgbuf->size;
-	return dmab->area;
+	return 0;
 
  _failed:
-	snd_free_sgbuf_pages(dmab); /* free the table */
-	return NULL;
+	snd_dma_sg_free(dmab); /* free the table */
+	return -ENOMEM;
 }
 
-/*
- * compute the max chunk size with continuous pages on sg-buffer
- */
-unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
-				      unsigned int ofs, unsigned int size)
+static dma_addr_t snd_dma_sg_get_addr(struct snd_dma_buffer *dmab,
+				      size_t offset)
+{
+	struct snd_sg_buf *sgbuf = dmab->private_data;
+	dma_addr_t addr;
+
+	addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
+	addr &= ~((dma_addr_t)PAGE_SIZE - 1);
+	return addr + offset % PAGE_SIZE;
+}
+
+static struct page *snd_dma_sg_get_page(struct snd_dma_buffer *dmab,
+					size_t offset)
+{
+	struct snd_sg_buf *sgbuf = dmab->private_data;
+	unsigned int idx = offset >> PAGE_SHIFT;
+
+	if (idx >= (unsigned int)sgbuf->pages)
+		return NULL;
+	return sgbuf->page_table[idx];
+}
+
+static unsigned int snd_dma_sg_get_chunk_size(struct snd_dma_buffer *dmab,
+					      unsigned int ofs,
+					      unsigned int size)
 {
 	struct snd_sg_buf *sg = dmab->private_data;
 	unsigned int start, end, pg;
 
-	if (!sg)
-		return size;
-
 	start = ofs >> PAGE_SHIFT;
 	end = (ofs + size - 1) >> PAGE_SHIFT;
 	/* check page continuity */
@@ -160,4 +181,11 @@ unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
 	/* ok, all on continuous pages */
 	return size;
 }
-EXPORT_SYMBOL(snd_sgbuf_get_chunk_size);
+
+const struct snd_malloc_ops snd_dma_sg_ops = {
+	.alloc = snd_dma_sg_alloc,
+	.free = snd_dma_sg_free,
+	.get_addr = snd_dma_sg_get_addr,
+	.get_page = snd_dma_sg_get_page,
+	.get_chunk_size = snd_dma_sg_get_chunk_size,
+};