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-rw-r--r--mm/backing-dev.c37
1 files changed, 37 insertions, 0 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 0e8ca03..707d0dc 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -11,6 +11,8 @@
#include <linux/writeback.h>
#include <linux/device.h>
+static atomic_long_t bdi_seq = ATOMIC_LONG_INIT(0);
+
void default_unplug_io_fn(struct backing_dev_info *bdi, struct page *page)
{
}
@@ -25,6 +27,11 @@ struct backing_dev_info default_backing_dev_info = {
};
EXPORT_SYMBOL_GPL(default_backing_dev_info);
+struct backing_dev_info noop_backing_dev_info = {
+ .name = "noop",
+};
+EXPORT_SYMBOL_GPL(noop_backing_dev_info);
+
static struct class *bdi_class;
/*
@@ -227,6 +234,9 @@ static struct device_attribute bdi_dev_attrs[] = {
static __init int bdi_class_init(void)
{
bdi_class = class_create(THIS_MODULE, "bdi");
+ if (IS_ERR(bdi_class))
+ return PTR_ERR(bdi_class);
+
bdi_class->dev_attrs = bdi_dev_attrs;
bdi_debug_init();
return 0;
@@ -712,6 +722,33 @@ void bdi_destroy(struct backing_dev_info *bdi)
}
EXPORT_SYMBOL(bdi_destroy);
+/*
+ * For use from filesystems to quickly init and register a bdi associated
+ * with dirty writeback
+ */
+int bdi_setup_and_register(struct backing_dev_info *bdi, char *name,
+ unsigned int cap)
+{
+ char tmp[32];
+ int err;
+
+ bdi->name = name;
+ bdi->capabilities = cap;
+ err = bdi_init(bdi);
+ if (err)
+ return err;
+
+ sprintf(tmp, "%.28s%s", name, "-%d");
+ err = bdi_register(bdi, NULL, tmp, atomic_long_inc_return(&bdi_seq));
+ if (err) {
+ bdi_destroy(bdi);
+ return err;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(bdi_setup_and_register);
+
static wait_queue_head_t congestion_wqh[2] = {
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[1])