Hi,
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?
+ mutex_lock(&cma_mutex);
+ bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
+ free_contig_range(pfn, count);
+ mutex_unlock(&cma_mutex);
+
+ return true;
+}
A.
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