Re: [Linaro-mm-sig] [PATCHv22 13/16] drivers: add Contiguous Memory Allocator

Hello,

On Tuesday, February 21, 2012 10:30 PM Aaro Koskinen wrote:

On Fri, 17 Feb 2012, Marek Szyprowski wrote:

...

+/**

• • dma_release_from_contiguous() - release allocated pages
• • @dev: Pointer to device for which the pages were allocated.
• • @pages: Allocated pages.
• • @count: Number of allocated pages.
• • This function releases memory allocated by dma_alloc_from_contiguous().
• • It returns false when provided pages do not belong to contiguous area and
• • true otherwise.
• */

+bool dma_release_from_contiguous(struct device *dev, struct page *pages,

• 		 int count)
  

+{

• struct cma *cma = dev_get_cma_area(dev);
• unsigned long pfn;
• if (!cma || !pages)

• return false;
  

• pr_debug("%s(page %p)\n", __func__, (void *)pages);
• pfn = page_to_pfn(pages);
• if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)

• return false;
  

• VM_BUG_ON(pfn + count > cma->base_pfn);

Are you sure the VM_BUG_ON() condition is correct here?

Thanks for pointing this bug. '+ cma->count' is missing in the second part.

Best regards