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.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

include/sound/memalloc.h

@@ -9,9 +9,8 @@
 #ifndef __SOUND_MEMALLOC_H
 #define __SOUND_MEMALLOC_H
 
-#include <asm/page.h>
-
 struct device;
+struct page;
 
 /*
  * buffer device info
@@ -64,59 +63,6 @@ static inline unsigned int snd_sgbuf_aligned_pages(size_t size)
 	return (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
 }
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * Scatter-Gather generic device pages
- */
-void *snd_malloc_sgbuf_pages(struct device *device,
-			     size_t size, struct snd_dma_buffer *dmab,
-			     size_t *res_size);
-int snd_free_sgbuf_pages(struct snd_dma_buffer *dmab);
-
-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;
-};
-
-/*
- * return the physical address at the corresponding offset
- */
-static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab,
-					   size_t offset)
-{
-	struct snd_sg_buf *sgbuf = dmab->private_data;
-	dma_addr_t addr;
-
-	if (!sgbuf)
-		return dmab->addr + offset;
-	addr = sgbuf->table[offset >> PAGE_SHIFT].addr;
-	addr &= ~((dma_addr_t)PAGE_SIZE - 1);
-	return addr + offset % PAGE_SIZE;
-}
-
-unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
-				      unsigned int ofs, unsigned int size);
-#else
-/* non-SG versions */
-static inline dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab,
-					    size_t offset)
-{
-	return dmab->addr + offset;
-}
-
-#define snd_sgbuf_get_chunk_size(dmab, ofs, size)	(size)
-
-#endif /* CONFIG_SND_DMA_SGBUF */
-
 /* allocate/release a buffer */
 int snd_dma_alloc_pages(int type, struct device *dev, size_t size,
 			struct snd_dma_buffer *dmab);
@@ -124,5 +70,10 @@ int snd_dma_alloc_pages_fallback(int type, struct device *dev, size_t size,
                                  struct snd_dma_buffer *dmab);
 void snd_dma_free_pages(struct snd_dma_buffer *dmab);
 
+dma_addr_t snd_sgbuf_get_addr(struct snd_dma_buffer *dmab, size_t offset);
+struct page *snd_sgbuf_get_page(struct snd_dma_buffer *dmab, size_t offset);
+unsigned int snd_sgbuf_get_chunk_size(struct snd_dma_buffer *dmab,
+				      unsigned int ofs, unsigned int size);
+
 #endif /* __SOUND_MEMALLOC_H */
 

include/sound/pcm.h

@@ -1254,14 +1254,6 @@ static inline int snd_pcm_lib_alloc_vmalloc_32_buffer
 
 #define snd_pcm_get_dma_buf(substream) ((substream)->runtime->dma_buffer_p)
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * SG-buffer handling
- */
-#define snd_pcm_substream_sgbuf(substream) \
-	snd_pcm_get_dma_buf(substream)->private_data
-#endif /* SND_DMA_SGBUF */
-
 /**
  * snd_pcm_sgbuf_get_addr - Get the DMA address at the corresponding offset
  * @substream: PCM substream

sound/core/memalloc_local.h

+// SPDX-License-Identifier: GPL-2.0-only
+#ifndef __MEMALLOC_LOCAL_H
+#define __MEMALLOC_LOCAL_H
+
+struct snd_malloc_ops {
+	int (*alloc)(struct snd_dma_buffer *dmab, size_t size);
+	void (*free)(struct snd_dma_buffer *dmab);
+	dma_addr_t (*get_addr)(struct snd_dma_buffer *dmab, size_t offset);
+	struct page *(*get_page)(struct snd_dma_buffer *dmab, size_t offset);
+	unsigned int (*get_chunk_size)(struct snd_dma_buffer *dmab,
+				       unsigned int ofs, unsigned int size);
+};
+
+#ifdef CONFIG_SND_DMA_SGBUF
+extern const struct snd_malloc_ops snd_dma_sg_ops;
+#endif
+
+#endif /* __MEMALLOC_LOCAL_H */

sound/core/pcm_local.h

@@ -65,11 +65,6 @@ void __snd_pcm_xrun(struct snd_pcm_substream *substream);
 void snd_pcm_group_init(struct snd_pcm_group *group);
 void snd_pcm_sync_stop(struct snd_pcm_substream *substream, bool sync_irq);
 
-#ifdef CONFIG_SND_DMA_SGBUF
-struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream,
-				    unsigned long offset);
-#endif
-
 #define PCM_RUNTIME_CHECK(sub) snd_BUG_ON(!(sub) || !(sub)->runtime)
 
 /* loop over all PCM substreams */

sound/core/pcm_memory.c

@@ -337,27 +337,6 @@ void snd_pcm_set_managed_buffer_all(struct snd_pcm *pcm, int type,
 }
 EXPORT_SYMBOL(snd_pcm_set_managed_buffer_all);
 
-#ifdef CONFIG_SND_DMA_SGBUF
-/*
- * snd_pcm_sgbuf_ops_page - get the page struct at the given offset
- * @substream: the pcm substream instance
- * @offset: the buffer offset
- *
- * Used as the page callback of PCM ops.
- *
- * Return: The page struct at the given buffer offset. %NULL on failure.
- */
-struct page *snd_pcm_sgbuf_ops_page(struct snd_pcm_substream *substream, unsigned long offset)
-{
-	struct snd_sg_buf *sgbuf = snd_pcm_substream_sgbuf(substream);
-
-	unsigned int idx = offset >> PAGE_SHIFT;
-	if (idx >= (unsigned int)sgbuf->pages)
-		return NULL;
-	return sgbuf->page_table[idx];
-}
-#endif /* CONFIG_SND_DMA_SGBUF */
-
 /**
  * snd_pcm_lib_malloc_pages - allocate the DMA buffer
  * @substream: the substream to allocate the DMA buffer to

sound/core/pcm_native.c

@@ -3644,24 +3644,6 @@ static int snd_pcm_mmap_control(struct snd_pcm_substream *substream, struct file
 }
 #endif /* coherent mmap */
 
-static inline struct page *
-snd_pcm_default_page_ops(struct snd_pcm_substream *substream, unsigned long ofs)
-{
-	void *vaddr = substream->runtime->dma_area + ofs;
-
-	switch (substream->dma_buffer.dev.type) {
-#ifdef CONFIG_SND_DMA_SGBUF
-	case SNDRV_DMA_TYPE_DEV_SG:
-	case SNDRV_DMA_TYPE_DEV_UC_SG:
-		return snd_pcm_sgbuf_ops_page(substream, ofs);
-#endif /* CONFIG_SND_DMA_SGBUF */
-	case SNDRV_DMA_TYPE_VMALLOC:
-		return vmalloc_to_page(vaddr);
-	default:
-		return virt_to_page(vaddr);
-	}
-}
-
 /*
  * fault callback for mmapping a RAM page
  */
@@ -3683,7 +3665,7 @@ static vm_fault_t snd_pcm_mmap_data_fault(struct vm_fault *vmf)
 	if (substream->ops->page)
 		page = substream->ops->page(substream, offset);
 	else
-		page = snd_pcm_default_page_ops(substream, offset);
+		page = snd_sgbuf_get_page(snd_pcm_get_dma_buf(substream), offset);
 	if (!page)
 		return VM_FAULT_SIGBUS;
 	get_page(page);

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,
+};