collectd: add percent calculation of bad block to ubi plugin

This patche adds the percent evaluation for the bad blocks.

Signed-off-by: Florian Eckert <fe@dev.tdt.de>
(cherry picked from commit b4e24c12)

utils/collectd/patches/935-ubi-add-percent.patch

+--- a/src/ubi.c
++++ b/src/ubi.c
+@@ -35,6 +35,9 @@
+ #define DEV_BAD_COUNT                                                          \
+   "bad_peb_count" // Count of bad physical eraseblocks on the underlying MTD
+                   // device.
++// Value reserved for bad block
++#define DEV_RESERVED_BAD_BLOCK "reserved_for_bad"
++
+ #define MAXIMUM_ERASE "max_ec" // Current maximum erase counter value
+ 
+ /*
+@@ -140,6 +143,35 @@ static inline int ubi_read_max_ec(const
+   return 0;
+ } /* int ubi_read_max_ec */
+ 
++static inline int ubi_read_percent(const char *dev_name) {
++  int ret;
++  int bcount;
++  int bblock;
++
++  ret = ubi_read_dev_attr(dev_name, DEV_BAD_COUNT, &bcount);
++
++  if (ret != 0) {
++    ERROR(PLUGIN_NAME " : Unable to read bad_peb_count");
++    return -1;
++  }
++
++  ret = ubi_read_dev_attr(dev_name, DEV_RESERVED_BAD_BLOCK, &bblock);
++
++  if (ret != 0) {
++    ERROR(PLUGIN_NAME " : Unable to read reserved_for_bad");
++    return -1;
++  }
++
++  if (bblock == 0) {
++    ERROR(PLUGIN_NAME " : Percentage value cannot be determined (reserved_for_bad = 0)");
++    return -2;
++  }
++
++  ubi_submit(dev_name, "percent", (gauge_t)((float_t)bcount / (float_t)bblock * 100.0));
++
++  return 0;
++} /* int ubi_read_percent */
++
+ static int ubi_read(void) {
+   DIR *dir;
+   struct dirent *dirent;
+@@ -155,6 +187,7 @@ static int ubi_read(void) {
+ 
+     ubi_read_dev_bad_count(dirent->d_name);
+     ubi_read_max_ec(dirent->d_name);
++    ubi_read_percent(dirent->d_name);
+   }
+ 
+   closedir(dir);