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Subject[PATCH v3 4/5] ALSA: emu10k1: make sure synth DMA pages are allocated with DMA functions
Date
Commit a5003fc04113 ("[ALSA] emu10k1 - simplify page allocation for synth")
switched from using the DMA allocator for synth DMA pages to manually
calling alloc_page().
However, this usage has an implicit assumption that the DMA address space
for the emu10k1-family chip is the same as the CPU physical address space
which is not true for a system with a IOMMU.

Since this made the synth part of the driver non-functional on such systems
let's effectively revert that commit (while keeping the
__synth_free_pages() simplification).

Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name>
---
Changes from v1: None in this patch.

Changes from v2: Keep the __synth_free_pages() simplification.

sound/pci/emu10k1/memory.c | 44 +++++++++++++++++++++++++++-----------------
1 file changed, 27 insertions(+), 17 deletions(-)

diff --git a/sound/pci/emu10k1/memory.c b/sound/pci/emu10k1/memory.c
index fcb04cbbc9ab..1d0ce7356bbd 100644
--- a/sound/pci/emu10k1/memory.c
+++ b/sound/pci/emu10k1/memory.c
@@ -461,10 +461,19 @@ static void get_single_page_range(struct snd_util_memhdr *hdr,
static void __synth_free_pages(struct snd_emu10k1 *emu, int first_page,
int last_page)
{
+ struct snd_dma_buffer dmab;
int page;

+ dmab.dev.type = SNDRV_DMA_TYPE_DEV;
+ dmab.dev.dev = snd_dma_pci_data(emu->pci);
+
for (page = first_page; page <= last_page; page++) {
- free_page((unsigned long)emu->page_ptr_table[page]);
+ if (emu->page_ptr_table[page] == NULL)
+ continue;
+ dmab.area = emu->page_ptr_table[page];
+ dmab.addr = emu->page_addr_table[page];
+ dmab.bytes = PAGE_SIZE;
+ snd_dma_free_pages(&dmab);
emu->page_addr_table[page] = 0;
emu->page_ptr_table[page] = NULL;
}
@@ -476,30 +485,31 @@ static void __synth_free_pages(struct snd_emu10k1 *emu, int first_page,
static int synth_alloc_pages(struct snd_emu10k1 *emu, struct snd_emu10k1_memblk *blk)
{
int page, first_page, last_page;
+ struct snd_dma_buffer dmab;

emu10k1_memblk_init(blk);
get_single_page_range(emu->memhdr, blk, &first_page, &last_page);
/* allocate kernel pages */
for (page = first_page; page <= last_page; page++) {
- /* first try to allocate from <4GB zone */
- struct page *p = alloc_page(GFP_KERNEL | GFP_DMA32 |
- __GFP_NOWARN);
- if (!p || (page_to_pfn(p) & ~(emu->dma_mask >> PAGE_SHIFT))) {
- if (p)
- __free_page(p);
- /* try to allocate from <16MB zone */
- p = alloc_page(GFP_ATOMIC | GFP_DMA |
- __GFP_NORETRY | /* no OOM-killer */
- __GFP_NOWARN);
- }
- if (!p) {
- __synth_free_pages(emu, first_page, page - 1);
- return -ENOMEM;
+ if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV,
+ snd_dma_pci_data(emu->pci),
+ PAGE_SIZE, &dmab) < 0)
+ goto __fail;
+ if (!is_valid_page(emu, dmab.addr)) {
+ snd_dma_free_pages(&dmab);
+ goto __fail;
}
- emu->page_addr_table[page] = page_to_phys(p);
- emu->page_ptr_table[page] = page_address(p);
+ emu->page_addr_table[page] = dmab.addr;
+ emu->page_ptr_table[page] = dmab.area;
}
return 0;
+
+__fail:
+ /* release allocated pages */
+ last_page = page - 1;
+ __synth_free_pages(emu, first_page, last_page);
+
+ return -ENOMEM;
}

/*
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