xen: make sysfs files behave as their names suggest
1: make "target_kb" only accept and produce a memory size in kilobytes.
2: add a second "target" file which produces output in bytes, and will accept
memparse input (scaled bytes)
This fixes the rather irritating problem that writing the same value
read back into target_kb would end up shrinking the domain by a factor
of 1024, with generally bad results.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Stable Kernel <stable@kernel.org>
Cc: "dan.magenheimer@oracle.com" <dan.magenheimer@oracle.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 2ba8f95..efa4b36 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -498,7 +498,7 @@
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
- target_bytes = memparse(buf, &endchar);
+ target_bytes = simple_strtoull(buf, &endchar, 0) * 1024;
balloon_set_new_target(target_bytes >> PAGE_SHIFT);
@@ -508,8 +508,39 @@
static SYSDEV_ATTR(target_kb, S_IRUGO | S_IWUSR,
show_target_kb, store_target_kb);
+
+static ssize_t show_target(struct sys_device *dev, struct sysdev_attribute *attr,
+ char *buf)
+{
+ return sprintf(buf, "%llu\n",
+ (u64)balloon_stats.target_pages << PAGE_SHIFT);
+}
+
+static ssize_t store_target(struct sys_device *dev,
+ struct sysdev_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ char *endchar;
+ unsigned long long target_bytes;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+
+ target_bytes = memparse(buf, &endchar);
+
+ balloon_set_new_target(target_bytes >> PAGE_SHIFT);
+
+ return count;
+}
+
+static SYSDEV_ATTR(target, S_IRUGO | S_IWUSR,
+ show_target, store_target);
+
+
static struct sysdev_attribute *balloon_attrs[] = {
&attr_target_kb,
+ &attr_target,
};
static struct attribute *balloon_info_attrs[] = {