Revision 30f92d62e5b41a94de2d0bbd677a6ea2fcfed74f authored by Akinobu Mita on 06 September 2017, 10:15:31 UTC, committed by Christoph Hellwig on 11 September 2017, 16:29:38 UTC
The initial chunk size for host memory buffer allocation is currently PAGE_SIZE << MAX_ORDER. MAX_ORDER order allocation is usually failed without CONFIG_DMA_CMA. So the HMB allocation is retried with chunk size PAGE_SIZE << (MAX_ORDER - 1) in general, but there is no problem if the retry allocation works correctly. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> [hch: rebased] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Keith Busch <keith.busch@intel.com> Cc: stable@vger.kernel.org
1 parent 92dc689
dma-virt.c
/*
* lib/dma-virt.c
*
* DMA operations that map to virtual addresses without flushing memory.
*/
#include <linux/export.h>
#include <linux/mm.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
static void *dma_virt_alloc(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t gfp,
unsigned long attrs)
{
void *ret;
ret = (void *)__get_free_pages(gfp, get_order(size));
if (ret)
*dma_handle = (uintptr_t)ret;
return ret;
}
static void dma_virt_free(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_addr,
unsigned long attrs)
{
free_pages((unsigned long)cpu_addr, get_order(size));
}
static dma_addr_t dma_virt_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs)
{
return (uintptr_t)(page_address(page) + offset);
}
static int dma_virt_map_sg(struct device *dev, struct scatterlist *sgl,
int nents, enum dma_data_direction dir,
unsigned long attrs)
{
int i;
struct scatterlist *sg;
for_each_sg(sgl, sg, nents, i) {
BUG_ON(!sg_page(sg));
sg_dma_address(sg) = (uintptr_t)sg_virt(sg);
sg_dma_len(sg) = sg->length;
}
return nents;
}
const struct dma_map_ops dma_virt_ops = {
.alloc = dma_virt_alloc,
.free = dma_virt_free,
.map_page = dma_virt_map_page,
.map_sg = dma_virt_map_sg,
};
EXPORT_SYMBOL(dma_virt_ops);
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