#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/device.h>
+
+
+static struct class *bdi_class;
+
+static ssize_t read_ahead_kb_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 long read_ahead_kb;
+ ssize_t ret = -EINVAL;
+
+ read_ahead_kb = simple_strtoul(buf, &end, 10);
+ if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
+ bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
+ ret = count;
+ }
+ return ret;
+}
+
+#define K(pages) ((pages) << (PAGE_SHIFT - 10))
+
+#define BDI_SHOW(name, expr) \
+static ssize_t name##_show(struct device *dev, \
+ struct device_attribute *attr, char *page) \
+{ \
+ struct backing_dev_info *bdi = dev_get_drvdata(dev); \
+ \
+ return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \
+}
+
+BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
+
+BDI_SHOW(reclaimable_kb, K(bdi_stat(bdi, BDI_RECLAIMABLE)))
+BDI_SHOW(writeback_kb, K(bdi_stat(bdi, BDI_WRITEBACK)))
+
+static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
+{
+ unsigned long thresh[3];
+
+ get_dirty_limits(&thresh[0], &thresh[1], &thresh[2], bdi);
+
+ return thresh[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)
+
+static ssize_t max_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_max_ratio(bdi, ratio);
+ if (!ret)
+ ret = count;
+ }
+ return ret;
+}
+BDI_SHOW(max_ratio, bdi->max_ratio)
+
+#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
+
+static struct device_attribute bdi_dev_attrs[] = {
+ __ATTR_RW(read_ahead_kb),
+ __ATTR_RO(reclaimable_kb),
+ __ATTR_RO(writeback_kb),
+ __ATTR_RO(dirty_kb),
+ __ATTR_RO(bdi_dirty_kb),
+ __ATTR_RW(min_ratio),
+ __ATTR_RW(max_ratio),
+ __ATTR_NULL,
+};
+
+static __init int bdi_class_init(void)
+{
+ bdi_class = class_create(THIS_MODULE, "bdi");
+ bdi_class->dev_attrs = bdi_dev_attrs;
+ return 0;
+}
+
+core_initcall(bdi_class_init);
+
+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
+ const char *fmt, ...)
+{
+ char *name;
+ va_list args;
+ int ret = 0;
+ struct device *dev;
+
+ va_start(args, fmt);
+ name = kvasprintf(GFP_KERNEL, fmt, args);
+ va_end(args);
+
+ if (!name)
+ return -ENOMEM;
+
+ dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
+ if (IS_ERR(dev)) {
+ ret = PTR_ERR(dev);
+ goto exit;
+ }
+
+ bdi->dev = dev;
+ dev_set_drvdata(bdi->dev, bdi);
+
+exit:
+ kfree(name);
+ return ret;
+}
+EXPORT_SYMBOL(bdi_register);
+
+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
+{
+ return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
+}
+EXPORT_SYMBOL(bdi_register_dev);
+
+void bdi_unregister(struct backing_dev_info *bdi)
+{
+ if (bdi->dev) {
+ device_unregister(bdi->dev);
+ bdi->dev = NULL;
+ }
+}
+EXPORT_SYMBOL(bdi_unregister);
+
+int bdi_init(struct backing_dev_info *bdi)
+{
+ int i;
+ int err;
+
+ bdi->dev = NULL;
+
+ bdi->min_ratio = 0;
+ bdi->max_ratio = 100;
+ bdi->max_prop_frac = PROP_FRAC_BASE;
+
+ for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
+ err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
+ if (err)
+ goto err;
+ }
+
+ bdi->dirty_exceeded = 0;
+ err = prop_local_init_percpu(&bdi->completions);
+
+ if (err) {
+err:
+ while (i--)
+ percpu_counter_destroy(&bdi->bdi_stat[i]);
+ }
+
+ return err;
+}
+EXPORT_SYMBOL(bdi_init);
+
+void bdi_destroy(struct backing_dev_info *bdi)
+{
+ int i;
+
+ bdi_unregister(bdi);
+
+ for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
+ percpu_counter_destroy(&bdi->bdi_stat[i]);
+
+ prop_local_destroy_percpu(&bdi->completions);
+}
+EXPORT_SYMBOL(bdi_destroy);
static wait_queue_head_t congestion_wqh[2] = {
__WAIT_QUEUE_HEAD_INITIALIZER(congestion_wqh[0]),
}
EXPORT_SYMBOL(congestion_wait);
-/**
- * congestion_end - wake up sleepers on a congested backing_dev_info
- * @rw: READ or WRITE
- */
-void congestion_end(int rw)
-{
- wait_queue_head_t *wqh = &congestion_wqh[rw];
-
- if (waitqueue_active(wqh))
- wake_up(wqh);
-}
-EXPORT_SYMBOL(congestion_end);