/**
* dma_contiguous_isolate() - isolate contiguous memory from the page allocator
* @dev: Pointer to device which owns the contiguous memory
*
* This function isolates contiguous memory from the page allocator. If some of
* the contiguous memory is allocated, it is reclaimed.
*/
int dma_contiguous_isolate(struct device *dev)
{
struct cma *cma = dev_get_cma_area(dev);
int ret;
int idx;
if (!cma)
return -ENODEV;
if (cma->count == 0)
return 0;
mutex_lock(&cma_mutex);
if (cma->isolated) {
mutex_unlock(&cma_mutex);
dev_err(dev, "Alread isolated!\n");
return 0;
}
idx = find_first_zero_bit(cma->bitmap, cma->count);
while (idx < cma->count) {
int idx_set;
idx_set = find_next_bit(cma->bitmap, cma->count, idx);
do {
ret = alloc_contig_range(cma->base_pfn + idx,
cma->base_pfn + idx_set,
MIGRATE_CMA);
} while (ret == -EBUSY);
if (ret < 0) {
mutex_unlock(&cma_mutex);
dma_contiguous_deisolate_until(dev, idx_set);
dev_err(dev, "Failed to isolate %#lx@%#010llx (%d).\n",
(idx_set - idx) * PAGE_SIZE,
PFN_PHYS(cma->base_pfn + idx), ret);
return ret;
}
idx = find_next_zero_bit(cma->bitmap, cma->count, idx_set);
}
cma->isolated = true;
mutex_unlock(&cma_mutex);
return 0;
}
/**
* dma_contiguous_deisolate() - return contiguous memory to the page allocator
* @dev: Pointer to device which owns the contiguous memory
*
* This function return the contiguous memory that is not allocated by CMA to
* the page allocator so that the kernel can allocate the contiguous memory.
*/
void dma_contiguous_deisolate(struct device *dev)
{
struct cma *cma = dev_get_cma_area(dev);
dma_contiguous_deisolate_until(dev, cma->count);
}