Merge remote-tracking branch 'v4l-dvb/master'

1 files changed, 44 insertions, 0 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1171a292e06e..2c92ac098a93 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -20,6 +20,7 @@
 #include <linux/shrinker.h>
 #include <linux/resource.h>
 #include <linux/page_ext.h>
+#include <linux/err.h>
 
 struct mempolicy;
 struct anon_vma;
@@ -1236,6 +1237,49 @@ long get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,
 		    int write, int force, struct page **pages);
 int get_user_pages_fast(unsigned long start, int nr_pages, int write,
 			struct page **pages);
+
+/* Container for pinned pfns / pages */
+struct frame_vector {
+	unsigned int nr_allocated;	/* Number of frames we have space for */
+	unsigned int nr_frames;	/* Number of frames stored in ptrs array */
+	bool got_ref;		/* Did we pin pages by getting page ref? */
+	bool is_pfns;		/* Does array contain pages or pfns? */
+	void *ptrs[0];		/* Array of pinned pfns / pages. Use
+				 * pfns_vector_pages() or pfns_vector_pfns()
+				 * for access */
+};
+
+struct frame_vector *frame_vector_create(unsigned int nr_frames);
+void frame_vector_destroy(struct frame_vector *vec);
+int get_vaddr_frames(unsigned long start, unsigned int nr_pfns,
+		     bool write, bool force, struct frame_vector *vec);
+void put_vaddr_frames(struct frame_vector *vec);
+int frame_vector_to_pages(struct frame_vector *vec);
+void frame_vector_to_pfns(struct frame_vector *vec);
+
+static inline unsigned int frame_vector_count(struct frame_vector *vec)
+{
+	return vec->nr_frames;
+}
+
+static inline struct page **frame_vector_pages(struct frame_vector *vec)
+{
+	if (vec->is_pfns) {
+		int err = frame_vector_to_pages(vec);
+
+		if (err)
+			return ERR_PTR(err);
+	}
+	return (struct page **)(vec->ptrs);
+}
+
+static inline unsigned long *frame_vector_pfns(struct frame_vector *vec)
+{
+	if (!vec->is_pfns)
+		frame_vector_to_pfns(vec);
+	return (unsigned long *)(vec->ptrs);
+}
+
 struct kvec;
 int get_kernel_pages(const struct kvec *iov, int nr_pages, int write,
 			struct page **pages);