ALSA: memalloc: Use DMA API for x86 WC page allocations, too

The memalloc helper used a house-made code for allocation of WC pages
on x86, since the standard DMA API doesn't cover it well.  Meanwhile,
the manually allocated pages won't work together with IOMMU, resulting
in faults, so we should switch to the DMA API in that case, instead.

This patch tries to switch back to DMA API for WC pages on x86, but
with some additional tweaks that are missing.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219087
Link: https://patch.msgid.link/20240801064808.31205-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/core/memalloc.c b/sound/core/memalloc.c
index f901504b5afc17aef00a1bf1dafb277098624e1a..428652fda926202cd0f4a856a7d59492754843f8 100644 (file)
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -492,40 +492,39 @@ static const struct snd_malloc_ops snd_dma_dev_ops = {
  */
 /* 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_pages(dmab->dev.dev, size, &dmab->addr, true);
-}
-
-static void snd_dma_wc_free(struct snd_dma_buffer *dmab)
-{
-       do_free_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);
-}
+#define x86_fallback(dmab)     (!get_dma_ops(dmab->dev.dev))
 #else
+#define x86_fallback(dmab)     false
+#endif
+
 static void *snd_dma_wc_alloc(struct snd_dma_buffer *dmab, size_t size)
 {
+       if (x86_fallback(dmab))
+               return do_alloc_pages(dmab->dev.dev, size, &dmab->addr, true);
        return dma_alloc_wc(dmab->dev.dev, size, &dmab->addr, DEFAULT_GFP);
 }
 
 static void snd_dma_wc_free(struct snd_dma_buffer *dmab)
 {
+       if (x86_fallback(dmab)) {
+               do_free_pages(dmab->area, dmab->bytes, true);
+               return;
+       }
        dma_free_wc(dmab->dev.dev, dmab->bytes, dmab->area, dmab->addr);
 }
 
 static int snd_dma_wc_mmap(struct snd_dma_buffer *dmab,
                           struct vm_area_struct *area)
 {
+#ifdef CONFIG_SND_DMA_SGBUF
+       if (x86_fallback(dmab)) {
+               area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
+               return snd_dma_continuous_mmap(dmab, area);
+       }
+#endif
        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,
@@ -548,7 +547,7 @@ static void *snd_dma_noncontig_alloc(struct snd_dma_buffer *dmab, size_t size)
        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 && x86_fallback(dmab))
                return snd_dma_sg_fallback_alloc(dmab, size);
 #endif
        if (!sgt)