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Subject[Xen-devel][RFC 2/3] xen/grant-table: Extend API to work with DMA buffers
Date
From: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
---
drivers/xen/grant-table.c | 49 +++++++++++++++++++++++++++++++++++++++
include/xen/grant_table.h | 7 ++++++
2 files changed, 56 insertions(+)

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index bb36b1e1dbcc..c27bcc420575 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -729,6 +729,55 @@ void gnttab_free_pages(int nr_pages, struct page **pages)
}
EXPORT_SYMBOL(gnttab_free_pages);

+int gnttab_dma_alloc_pages(struct device *dev, bool coherent,
+ int nr_pages, struct page **pages,
+ void **vaddr, dma_addr_t *dev_bus_addr)
+{
+ int i;
+ int ret;
+
+ ret = alloc_dma_xenballooned_pages(dev, coherent, nr_pages, pages,
+ vaddr, dev_bus_addr);
+ if (ret < 0)
+ return ret;
+
+ for (i = 0; i < nr_pages; i++) {
+#if BITS_PER_LONG < 64
+ struct xen_page_foreign *foreign;
+
+ foreign = kzalloc(sizeof(*foreign), GFP_KERNEL);
+ if (!foreign) {
+ gnttab_dma_free_pages(dev, flags, nr_pages, pages,
+ *vaddr, *dev_bus_addr);
+ return -ENOMEM;
+ }
+ set_page_private(pages[i], (unsigned long)foreign);
+#endif
+ SetPagePrivate(pages[i]);
+ }
+ return 0;
+}
+EXPORT_SYMBOL(gnttab_dma_alloc_pages);
+
+void gnttab_dma_free_pages(struct device *dev, bool coherent,
+ int nr_pages, struct page **pages,
+ void *vaddr, dma_addr_t dev_bus_addr)
+{
+ int i;
+
+ for (i = 0; i < nr_pages; i++) {
+ if (PagePrivate(pages[i])) {
+#if BITS_PER_LONG < 64
+ kfree((void *)page_private(pages[i]));
+#endif
+ ClearPagePrivate(pages[i]);
+ }
+ }
+ free_dma_xenballooned_pages(dev, coherent, nr_pages, pages,
+ vaddr, dev_bus_addr);
+}
+EXPORT_SYMBOL(gnttab_dma_free_pages);
+
/* Handling of paged out grant targets (GNTST_eagain) */
#define MAX_DELAY 256
static inline void
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 34b1379f9777..20ee2b5ba965 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -195,6 +195,13 @@ void gnttab_free_auto_xlat_frames(void);
int gnttab_alloc_pages(int nr_pages, struct page **pages);
void gnttab_free_pages(int nr_pages, struct page **pages);

+int gnttab_dma_alloc_pages(struct device *dev, bool coherent,
+ int nr_pages, struct page **pages,
+ void **vaddr, dma_addr_t *dev_bus_addr);
+void gnttab_dma_free_pages(struct device *dev, bool coherent,
+ int nr_pages, struct page **pages,
+ void *vaddr, dma_addr_t dev_bus_addr);
+
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count);
--
2.17.0
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