Commit a8d302a0 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: memalloc: Revive x86-specific WC page allocations again 

We dropped the x86-specific hack for WC-page allocations with a hope
that the standard dma_alloc_wc() works nowadays.  Alas, it doesn't,
and we need to take back some workaround again, but in a different
form, as the previous one was broken for some platforms.

This patch re-introduces the x86-specific WC-page allocations, but it
uses rather the manual page allocations instead of
dma_alloc_coherent().  The use of dma_alloc_coherent() was also a
potential problem in the recent addition of the fallback allocation
for noncontig pages, and this patch eliminates both at once.

Fixes: 9882d63b ("ALSA: memalloc: Drop x86-specific hack for WC allocations")
Cc: <stable@vger.kernel.org>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=216363
Link: https://lore.kernel.org/r/20220821155911.10715-1-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 1c23f9e6

sound/core/memalloc.c

+71 −16
Original line number Diff line number Diff line
@@ -20,6 +20,13 @@ 


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)
@@ -277,16 +284,21 @@ EXPORT_SYMBOL(snd_sgbuf_get_chunk_size); 
/*

 * Continuous pages allocator

 */

static void *snd_dma_continuous_alloc(struct snd_dma_buffer *dmab, size_t size)

static void *do_alloc_pages(size_t size, dma_addr_t *addr, gfp_t gfp)

{

	gfp_t gfp = snd_mem_get_gfp_flags(dmab, GFP_KERNEL);

	void *p = alloc_pages_exact(size, gfp);



	if (p)

		dmab->addr = page_to_phys(virt_to_page(p));

		*addr = page_to_phys(virt_to_page(p));

	return p;

}



static void *snd_dma_continuous_alloc(struct snd_dma_buffer *dmab, size_t size)

{

	return do_alloc_pages(size, &dmab->addr,

			      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);
@@ -463,6 +475,25 @@ static const struct snd_malloc_ops snd_dma_dev_ops = { 
/*

 * Write-combined pages

 */

/* x86-specific allocations */

#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);

}



static void snd_dma_wc_free(struct snd_dma_buffer *dmab)

{

	do_free_fallback_pages(dmab->area, dmab->bytes, true);

}



static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab,

			   struct vm_area_struct *area)

{

	area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);

	return snd_dma_continuous_mmap(dmab, area);

}

#else

static void *snd_dma_wc_alloc(struct snd_dma_buffer *dmab, size_t size)

{

	return dma_alloc_wc(dmab->dev.dev, size, &dmab->addr, DEFAULT_GFP);
@@ -479,6 +510,7 @@ static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab, 
	return dma_mmap_wc(dmab->dev.dev, area,

			   dmab->area, dmab->addr, dmab->bytes);

}

#endif /* CONFIG_SND_DMA_SGBUF */



static const struct snd_malloc_ops snd_dma_wc_ops = {

	.alloc = snd_dma_wc_alloc,
@@ -486,10 +518,6 @@ static const struct snd_malloc_ops snd_dma_wc_ops = { 
	.mmap = snd_dma_wc_mmap,

};



#ifdef CONFIG_SND_DMA_SGBUF

static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size);

#endif



/*

 * Non-contiguous pages allocator

 */
@@ -669,6 +697,37 @@ 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;
@@ -679,14 +738,11 @@ struct snd_dma_sg_fallback { 
static void __snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab,

				       struct snd_dma_sg_fallback *sgbuf)

{

	bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;

	size_t i;



	if (sgbuf->count && dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)

		set_pages_array_wb(sgbuf->pages, sgbuf->count);

	for (i = 0; i < sgbuf->count && sgbuf->pages[i]; i++)

		dma_free_coherent(dmab->dev.dev, PAGE_SIZE,

				  page_address(sgbuf->pages[i]),

				  sgbuf->addrs[i]);

		do_free_fallback_pages(page_address(sgbuf->pages[i]), PAGE_SIZE, wc);

	kvfree(sgbuf->pages);

	kvfree(sgbuf->addrs);

	kfree(sgbuf);
@@ -698,6 +754,7 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size) 
	struct page **pages;

	size_t i, count;

	void *p;

	bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK;



	sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);

	if (!sgbuf)
@@ -712,15 +769,13 @@ 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 = dma_alloc_coherent(dmab->dev.dev, PAGE_SIZE,

				       &sgbuf->addrs[i], DEFAULT_GFP);

		p = do_alloc_fallback_pages(dmab->dev.dev, PAGE_SIZE,

					    &sgbuf->addrs[i], wc);

		if (!p)

			goto error;

		sgbuf->pages[i] = virt_to_page(p);

	}



	if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG_FALLBACK)

		set_pages_array_wc(pages, count);

	p = vmap(pages, count, VM_MAP, PAGE_KERNEL);

	if (!p)

		goto error;