1 files changed, 30 insertions, 0 deletions
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
new file mode 100644
index 000000000000..075cacc389e1
--- /dev/null
+++ b/include/linux/backing-dev.h
@@ -0,0 +1,30 @@
+/*
+ * include/linux/backing-dev.h
+ *
+ * low-level device information and state which is propagated up through
+ * to high-level code.
+ */
+
+#ifndef _LINUX_BACKING_DEV_H
+#define _LINUX_BACKING_DEV_H
+
+/*
+ * Bits in backing_dev_info.state
+ */
+enum bdi_state {
+	BDI_pdflush,		/* A pdflush thread is working this device */
+	BDI_unused,		/* Available bits start here */
+};
+
+struct backing_dev_info {
+	unsigned long ra_pages;	/* max readahead in PAGE_CACHE_SIZE units */
+	unsigned long state;	/* Always use atomic bitops on this */
+};
+
+extern struct backing_dev_info default_backing_dev_info;
+
+int writeback_acquire(struct backing_dev_info *bdi);
+int writeback_in_progress(struct backing_dev_info *bdi);
+void writeback_release(struct backing_dev_info *bdi);
+
+#endif		/* _LINUX_BACKING_DEV_H */