[PATCH v4 2/9] xen/grant-table: Make set/clear page private code shared

From: Oleksandr Andrushchenko
Date: Fri Jun 15 2018 - 02:28:18 EST


From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>

Make set/clear page private code shared and accessible to
other kernel modules which can re-use these instead of open-coding.

Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
drivers/xen/grant-table.c | 54 +++++++++++++++++++++++++--------------
include/xen/grant_table.h | 3 +++
2 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/drivers/xen/grant-table.c b/drivers/xen/grant-table.c
index ba36ff3e4903..dbb48a89e987 100644
--- a/drivers/xen/grant-table.c
+++ b/drivers/xen/grant-table.c
@@ -769,29 +769,18 @@ void gnttab_free_auto_xlat_frames(void)
}
EXPORT_SYMBOL_GPL(gnttab_free_auto_xlat_frames);

-/**
- * gnttab_alloc_pages - alloc pages suitable for grant mapping into
- * @nr_pages: number of pages to alloc
- * @pages: returns the pages
- */
-int gnttab_alloc_pages(int nr_pages, struct page **pages)
+int gnttab_pages_set_private(int nr_pages, struct page **pages)
{
int i;
- int ret;
-
- ret = alloc_xenballooned_pages(nr_pages, pages);
- 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_free_pages(nr_pages, pages);
+ if (!foreign)
return -ENOMEM;
- }
+
set_page_private(pages[i], (unsigned long)foreign);
#endif
SetPagePrivate(pages[i]);
@@ -799,14 +788,30 @@ int gnttab_alloc_pages(int nr_pages, struct page **pages)

return 0;
}
-EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
+EXPORT_SYMBOL_GPL(gnttab_pages_set_private);

/**
- * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
- * @nr_pages; number of pages to free
- * @pages: the pages
+ * gnttab_alloc_pages - alloc pages suitable for grant mapping into
+ * @nr_pages: number of pages to alloc
+ * @pages: returns the pages
*/
-void gnttab_free_pages(int nr_pages, struct page **pages)
+int gnttab_alloc_pages(int nr_pages, struct page **pages)
+{
+ int ret;
+
+ ret = alloc_xenballooned_pages(nr_pages, pages);
+ if (ret < 0)
+ return ret;
+
+ ret = gnttab_pages_set_private(nr_pages, pages);
+ if (ret < 0)
+ gnttab_free_pages(nr_pages, pages);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(gnttab_alloc_pages);
+
+void gnttab_pages_clear_private(int nr_pages, struct page **pages)
{
int i;

@@ -818,6 +823,17 @@ void gnttab_free_pages(int nr_pages, struct page **pages)
ClearPagePrivate(pages[i]);
}
}
+}
+EXPORT_SYMBOL_GPL(gnttab_pages_clear_private);
+
+/**
+ * gnttab_free_pages - free pages allocated by gnttab_alloc_pages()
+ * @nr_pages; number of pages to free
+ * @pages: the pages
+ */
+void gnttab_free_pages(int nr_pages, struct page **pages)
+{
+ gnttab_pages_clear_private(nr_pages, pages);
free_xenballooned_pages(nr_pages, pages);
}
EXPORT_SYMBOL_GPL(gnttab_free_pages);
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 2e37741f6b8d..de03f2542bb7 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -198,6 +198,9 @@ 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_pages_set_private(int nr_pages, struct page **pages);
+void gnttab_pages_clear_private(int nr_pages, struct page **pages);
+
int gnttab_map_refs(struct gnttab_map_grant_ref *map_ops,
struct gnttab_map_grant_ref *kmap_ops,
struct page **pages, unsigned int count);
--
2.17.1