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ALSA: memalloc: Use proper DMA mapping API for x86 S/G buffer allocations

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The fallback S/G buffer allocation for x86 used the addresses deduced
from the page allocations blindly.  It broke the allocations on IOMMU
and made us to work around with a hackish DMA ops check.

For cleaning up those messes, this patch switches to the proper DMA
mapping API usages with the standard sg-table instead.

By introducing the sg-table, the address table isn't needed, but for
keeping the original allocation sizes for freeing, replace it with the
array keeping the number of pages.

The get_addr callback is changed to use the existing one for
non-contiguous buffers.  (Also it's the reason sg_table is put at the
beginning of struct snd_dma_sg_fallback.)

And finally, the hackish workaround that checks the DMA ops is
dropped now.

Link: https://patch.msgid.link/20240912155227.4078-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2024-09-12 17:52:25 +02:00
parent c880a51466
commit 0b9f2bd00f
1 changed files with 36 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
sound/core/memalloc.c
View File

@ -680,43 +680,43 @@ static const struct snd_malloc_ops snd_dma_noncontig_ops = {
#ifdef CONFIG_SND_DMA_SGBUF
/* Fallback SG-buffer allocations for x86 */
struct snd_dma_sg_fallback {
struct sg_table sgt; /* used by get_addr - must be the first item */
size_t count;
struct page **pages;
/* DMA address array; the first page contains #pages in ~PAGE_MASK */
dma_addr_t *addrs;
unsigned int *npages;
};
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;
size_t i, size;
if (sgbuf->pages && sgbuf->addrs) {
if (sgbuf->pages && sgbuf->npages) {
i = 0;
while (i < sgbuf->count) {
if (!sgbuf->pages[i] || !sgbuf->addrs[i])
break;
size = sgbuf->addrs[i] & ~PAGE_MASK;
if (WARN_ON(!size))
size = sgbuf->npages[i];
if (!size)
break;
do_free_pages(page_address(sgbuf->pages[i]),
size << PAGE_SHIFT, false);
size << PAGE_SHIFT, wc);
i += size;
}
}
kvfree(sgbuf->pages);
kvfree(sgbuf->addrs);
kvfree(sgbuf->npages);
kfree(sgbuf);
}
/* fallback manual S/G buffer allocations */
static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
{
bool wc = dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG;
struct snd_dma_sg_fallback *sgbuf;
struct page **pagep, *curp;
size_t chunk, npages;
dma_addr_t *addrp;
size_t chunk;
dma_addr_t addr;
unsigned int idx, npages;
void *p;
sgbuf = kzalloc(sizeof(*sgbuf), GFP_KERNEL);
@ -725,16 +725,16 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
size = PAGE_ALIGN(size);
sgbuf->count = size >> PAGE_SHIFT;
sgbuf->pages = kvcalloc(sgbuf->count, sizeof(*sgbuf->pages), GFP_KERNEL);
sgbuf->addrs = kvcalloc(sgbuf->count, sizeof(*sgbuf->addrs), GFP_KERNEL);
if (!sgbuf->pages || !sgbuf->addrs)
sgbuf->npages = kvcalloc(sgbuf->count, sizeof(*sgbuf->npages), GFP_KERNEL);
if (!sgbuf->pages || !sgbuf->npages)
goto error;
pagep = sgbuf->pages;
addrp = sgbuf->addrs;
chunk = (PAGE_SIZE - 1) << PAGE_SHIFT; /* to fit in low bits in addrs */
chunk = size;
idx = 0;
while (size > 0) {
chunk = min(size, chunk);
p = do_alloc_pages(dmab->dev.dev, chunk, &addr, false);
p = do_alloc_pages(dmab->dev.dev, chunk, &addr, wc);
if (!p) {
if (chunk <= PAGE_SIZE)
goto error;
@ -746,27 +746,33 @@ static void *snd_dma_sg_fallback_alloc(struct snd_dma_buffer *dmab, size_t size)
size -= chunk;
/* fill pages */
npages = chunk >> PAGE_SHIFT;
*addrp = npages; /* store in lower bits */
sgbuf->npages[idx] = npages;
idx += npages;
curp = virt_to_page(p);
while (npages--) {
while (npages--)
*pagep++ = curp++;
*addrp++ |= addr;
addr += PAGE_SIZE;
}
}
if (sg_alloc_table_from_pages(&sgbuf->sgt, sgbuf->pages, sgbuf->count,
0, sgbuf->count << PAGE_SHIFT, GFP_KERNEL))
goto error;
if (dma_map_sgtable(dmab->dev.dev, &sgbuf->sgt, DMA_BIDIRECTIONAL, 0))
goto error_dma_map;
p = vmap(sgbuf->pages, sgbuf->count, VM_MAP, PAGE_KERNEL);
if (!p)
goto error;
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
set_pages_array_wc(sgbuf->pages, sgbuf->count);
goto error_vmap;
dmab->private_data = sgbuf;
/* store the first page address for convenience */
dmab->addr = sgbuf->addrs[0] & PAGE_MASK;
dmab->addr = snd_sgbuf_get_addr(dmab, 0);
return p;
error_vmap:
dma_unmap_sgtable(dmab->dev.dev, &sgbuf->sgt, DMA_BIDIRECTIONAL, 0);
error_dma_map:
sg_free_table(&sgbuf->sgt);
error:
__snd_dma_sg_fallback_free(dmab, sgbuf);
return NULL;
@ -776,21 +782,12 @@ static void snd_dma_sg_fallback_free(struct snd_dma_buffer *dmab)
{
struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
if (dmab->dev.type == SNDRV_DMA_TYPE_DEV_WC_SG)
set_pages_array_wb(sgbuf->pages, sgbuf->count);
vunmap(dmab->area);
dma_unmap_sgtable(dmab->dev.dev, &sgbuf->sgt, DMA_BIDIRECTIONAL, 0);
sg_free_table(&sgbuf->sgt);
__snd_dma_sg_fallback_free(dmab, dmab->private_data);
}
static dma_addr_t snd_dma_sg_fallback_get_addr(struct snd_dma_buffer *dmab,
size_t offset)
{
struct snd_dma_sg_fallback *sgbuf = dmab->private_data;
size_t index = offset >> PAGE_SHIFT;
return (sgbuf->addrs[index] & PAGE_MASK) | (offset & ~PAGE_MASK);
}
static int snd_dma_sg_fallback_mmap(struct snd_dma_buffer *dmab,
struct vm_area_struct *area)
{
@ -816,10 +813,6 @@ static void *snd_dma_sg_alloc(struct snd_dma_buffer *dmab, size_t size)
return p;
dmab->dev.type = type; /* restore the type */
/* if IOMMU is present but failed, give up */
if (get_dma_ops(dmab->dev.dev))
return NULL;
/* try fallback */
return snd_dma_sg_fallback_alloc(dmab, size);
}
@ -827,7 +820,8 @@ static const struct snd_malloc_ops snd_dma_sg_ops = {
.alloc = snd_dma_sg_alloc,
.free = snd_dma_sg_fallback_free,
.mmap = snd_dma_sg_fallback_mmap,
.get_addr = snd_dma_sg_fallback_get_addr,
/* reuse noncontig helper */
.get_addr = snd_dma_noncontig_get_addr,
/* reuse vmalloc helpers */
.get_page = snd_dma_vmalloc_get_page,
.get_chunk_size = snd_dma_vmalloc_get_chunk_size,