1 files changed, 21 insertions, 0 deletions

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 847eabe4824c..4967fb176e53 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -55,6 +55,24 @@ static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
 BDI_SHOW(dirty_kb, K(get_dirty(bdi, 1)))
 BDI_SHOW(bdi_dirty_kb, K(get_dirty(bdi, 2)))
 
+static ssize_t min_ratio_store(struct device *dev,
+                struct device_attribute *attr, const char *buf, size_t count)
+{
+        struct backing_dev_info *bdi = dev_get_drvdata(dev);
+        char *end;
+        unsigned int ratio;
+        ssize_t ret = -EINVAL;
+
+        ratio = simple_strtoul(buf, &end, 10);
+        if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
+                ret = bdi_set_min_ratio(bdi, ratio);
+                if (!ret)
+                        ret = count;
+        }
+        return ret;
+}
+BDI_SHOW(min_ratio, bdi->min_ratio)
+
 #define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
 
 static struct device_attribute bdi_dev_attrs[] = {
@@ -63,6 +81,7 @@ static struct device_attribute bdi_dev_attrs[] = {
         __ATTR_RO(writeback_kb),
         __ATTR_RO(dirty_kb),
         __ATTR_RO(bdi_dirty_kb),
+        __ATTR_RW(min_ratio),
         __ATTR_NULL,
 };
 
@@ -127,6 +146,8 @@ int bdi_init(struct backing_dev_info *bdi)
 
         bdi->dev = NULL;
 
+        bdi->min_ratio = 0;
+
         for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
                 err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
                 if (err)