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firewire: core: use common kernel API to allocate and release a batch of pages 

The pair of alloc_pages_bulk() and release_pages() are convenient to
allocate and release a batch of pages.

This commit utilizes the pair to maintain pages for isochronous DMA
context.

Link: https://lore.kernel.org/r/20260110013911.19160-5-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
This commit is contained in:
Takashi Sakamoto 2026-01-10 10:39:07 +09:00
parent a69a9e630d
commit c2f60aa160
1 changed files with 12 additions and 14 deletions
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26
drivers/firewire/core-iso.c
View File

@ -31,22 +31,18 @@
int fw_iso_buffer_alloc(struct fw_iso_buffer *buffer, int page_count)
{
struct page **page_array __free(kfree) = kcalloc(page_count, sizeof(page_array[0]), GFP_KERNEL);
int i;
if (!page_array)
return -ENOMEM;
for (i = 0; i < page_count; ++i) {
struct page *page = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
if (!page)
break;
page_array[i] = page;
}
if (i < page_count) {
while (i-- > 0)
__free_page(page_array[i]);
// Retrieve noncontiguous pages. The descriptors for 1394 OHCI isochronous DMA contexts
// have a set of address and length per each, while the reason to use pages is the
// convenience to map them into virtual address space of user process.
unsigned long nr_populated = alloc_pages_bulk(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO,
page_count, page_array);
if (nr_populated != page_count) {
// Assuming the above call fills page_array sequentially from the beginning.
release_pages(page_array, nr_populated);
return -ENOMEM;
}
@ -64,7 +60,10 @@ int fw_iso_buffer_map_dma(struct fw_iso_buffer *buffer, struct fw_card *card,
buffer->direction = direction;
// Retrieve DMA mapping addresses for the pages. They are not contiguous. Maintain the cache
// coherency for the pages by hand.
for (i = 0; i < buffer->page_count; i++) {
// The dma_map_phys() with a physical address per page is available here, instead.
address = dma_map_page(card->device, buffer->pages[i],
0, PAGE_SIZE, direction);
if (dma_mapping_error(card->device, address))
@ -109,8 +108,7 @@ void fw_iso_buffer_destroy(struct fw_iso_buffer *buffer,
}
if (buffer->pages) {
for (int i = 0; i < buffer->page_count; ++i)
__free_page(buffer->pages[i]);
release_pages(buffer->pages, buffer->page_count);
kfree(buffer->pages);
buffer->pages = NULL;
}