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@@ -4,12 +4,129 @@
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#include <linux/fs.h>
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#include <linux/sched.h>
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#include <linux/module.h>
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+#include <linux/writeback.h>
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+#include <linux/device.h>
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+
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+
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+static struct class *bdi_class;
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+
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+static ssize_t read_ahead_kb_store(struct device *dev,
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+ struct device_attribute *attr,
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+ const char *buf, size_t count)
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+{
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+ struct backing_dev_info *bdi = dev_get_drvdata(dev);
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+ char *end;
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+ unsigned long read_ahead_kb;
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+ ssize_t ret = -EINVAL;
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+
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+ read_ahead_kb = simple_strtoul(buf, &end, 10);
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+ if (*buf && (end[0] == '\0' || (end[0] == '\n' && end[1] == '\0'))) {
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+ bdi->ra_pages = read_ahead_kb >> (PAGE_SHIFT - 10);
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+ ret = count;
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+ }
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+ return ret;
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+}
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+
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+#define K(pages) ((pages) << (PAGE_SHIFT - 10))
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+
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+#define BDI_SHOW(name, expr) \
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+static ssize_t name##_show(struct device *dev, \
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+ struct device_attribute *attr, char *page) \
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+{ \
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+ struct backing_dev_info *bdi = dev_get_drvdata(dev); \
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+ \
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+ return snprintf(page, PAGE_SIZE-1, "%lld\n", (long long)expr); \
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+}
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+
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+BDI_SHOW(read_ahead_kb, K(bdi->ra_pages))
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+
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+BDI_SHOW(reclaimable_kb, K(bdi_stat(bdi, BDI_RECLAIMABLE)))
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+BDI_SHOW(writeback_kb, K(bdi_stat(bdi, BDI_WRITEBACK)))
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+
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+static inline unsigned long get_dirty(struct backing_dev_info *bdi, int i)
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+{
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+ unsigned long thresh[3];
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+
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+ get_dirty_limits(&thresh[0], &thresh[1], &thresh[2], bdi);
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+
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+ return thresh[i];
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+}
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+
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+BDI_SHOW(dirty_kb, K(get_dirty(bdi, 1)))
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+BDI_SHOW(bdi_dirty_kb, K(get_dirty(bdi, 2)))
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+
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+#define __ATTR_RW(attr) __ATTR(attr, 0644, attr##_show, attr##_store)
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+
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+static struct device_attribute bdi_dev_attrs[] = {
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+ __ATTR_RW(read_ahead_kb),
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+ __ATTR_RO(reclaimable_kb),
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+ __ATTR_RO(writeback_kb),
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+ __ATTR_RO(dirty_kb),
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+ __ATTR_RO(bdi_dirty_kb),
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+ __ATTR_NULL,
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+};
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+
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+static __init int bdi_class_init(void)
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+{
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+ bdi_class = class_create(THIS_MODULE, "bdi");
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+ bdi_class->dev_attrs = bdi_dev_attrs;
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+ return 0;
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+}
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+
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+core_initcall(bdi_class_init);
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+
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+int bdi_register(struct backing_dev_info *bdi, struct device *parent,
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+ const char *fmt, ...)
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+{
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+ char *name;
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+ va_list args;
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+ int ret = 0;
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+ struct device *dev;
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+
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+ va_start(args, fmt);
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+ name = kvasprintf(GFP_KERNEL, fmt, args);
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+ va_end(args);
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+
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+ if (!name)
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+ return -ENOMEM;
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+
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+ dev = device_create(bdi_class, parent, MKDEV(0, 0), name);
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+ if (IS_ERR(dev)) {
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+ ret = PTR_ERR(dev);
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+ goto exit;
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+ }
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+
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+ bdi->dev = dev;
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+ dev_set_drvdata(bdi->dev, bdi);
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+
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+exit:
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+ kfree(name);
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+ return ret;
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+}
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+EXPORT_SYMBOL(bdi_register);
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+
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+int bdi_register_dev(struct backing_dev_info *bdi, dev_t dev)
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+{
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+ return bdi_register(bdi, NULL, "%u:%u", MAJOR(dev), MINOR(dev));
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+}
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+EXPORT_SYMBOL(bdi_register_dev);
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+
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+void bdi_unregister(struct backing_dev_info *bdi)
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+{
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+ if (bdi->dev) {
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+ device_unregister(bdi->dev);
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+ bdi->dev = NULL;
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+ }
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+}
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+EXPORT_SYMBOL(bdi_unregister);
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int bdi_init(struct backing_dev_info *bdi)
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{
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int i;
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int err;
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+ bdi->dev = NULL;
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+
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for (i = 0; i < NR_BDI_STAT_ITEMS; i++) {
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err = percpu_counter_init_irq(&bdi->bdi_stat[i], 0);
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if (err)
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@@ -33,6 +150,8 @@ void bdi_destroy(struct backing_dev_info *bdi)
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{
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int i;
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+ bdi_unregister(bdi);
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+
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for (i = 0; i < NR_BDI_STAT_ITEMS; i++)
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percpu_counter_destroy(&bdi->bdi_stat[i]);
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