xen: add helpers for caching grant mapping pages
Instead of having similar helpers in multiple backend drivers use
common helpers for caching pages allocated via gnttab_alloc_pages().
Make use of those helpers in blkback and scsiback.
Cc: <[email protected]> # 5.9
Signed-off-by: Juergen Gross <[email protected]>
Reviewed-by: Boris Ostrovsky <[email protected]>
Signed-off-by: Juergen Gross <[email protected]>
diff --git a/include/xen/grant_table.h b/include/xen/grant_table.h
index 9bc5bc0..c6ef8ff 100644
--- a/include/xen/grant_table.h
+++ b/include/xen/grant_table.h
@@ -198,6 +198,19 @@ 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);
+struct gnttab_page_cache {
+ spinlock_t lock;
+ struct list_head pages;
+ unsigned int num_pages;
+};
+
+void gnttab_page_cache_init(struct gnttab_page_cache *cache);
+int gnttab_page_cache_get(struct gnttab_page_cache *cache, struct page **page);
+void gnttab_page_cache_put(struct gnttab_page_cache *cache, struct page **page,
+ unsigned int num);
+void gnttab_page_cache_shrink(struct gnttab_page_cache *cache,
+ unsigned int num);
+
#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
struct gnttab_dma_alloc_args {
/* Device for which DMA memory will be/was allocated. */
