From f94934472f6325db33a45ca5a3a29e371085e507 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Sat, 21 Aug 2021 21:47:19 +0200
Subject: [PATCH] Linux: rework disk-io parsing

Generalize sub-diskname handling, like sdb1/sdb2, to not count the
usage twice with the aggregate top-diskname, like sdb.
Rely on /proc/diskstats being ordered, e.g. no sub-diskname precedes its
top-diskname.

Closes: #675
---
 linux/Platform.c | 19 +++++--------------
 1 file changed, 5 insertions(+), 14 deletions(-)

diff --git a/linux/Platform.c b/linux/Platform.c
index 7d1c190a..05023d50 100644
--- a/linux/Platform.c
+++ b/linux/Platform.c
@@ -543,6 +543,8 @@ bool Platform_getDiskIO(DiskIOData* data) {
    if (!fd)
       return false;
 
+   char lastTopDisk[32] = { '\0' };
+
    unsigned long long int read_sum = 0, write_sum = 0, timeSpend_sum = 0;
    char lineBuffer[256];
    while (fgets(lineBuffer, sizeof(lineBuffer), fd)) {
@@ -556,22 +558,11 @@ bool Platform_getDiskIO(DiskIOData* data) {
             continue;
 
          /* only count root disks, e.g. do not count IO from sda and sda1 twice */
-         if ((diskname[0] == 's' || diskname[0] == 'h')
-             && diskname[1] == 'd'
-             && isalpha((unsigned char)diskname[2])
-             && isdigit((unsigned char)diskname[3]))
+         if (lastTopDisk[0] && String_startsWith(diskname, lastTopDisk))
             continue;
 
-         /* only count root disks, e.g. do not count IO from mmcblk0 and mmcblk0p1 twice */
-         if (diskname[0] == 'm'
-             && diskname[1] == 'm'
-             && diskname[2] == 'c'
-             && diskname[3] == 'b'
-             && diskname[4] == 'l'
-             && diskname[5] == 'k'
-             && isdigit((unsigned char)diskname[6])
-             && diskname[7] == 'p')
-            continue;
+         /* This assumes disks are listed directly before any of their partitions */
+         String_safeStrncpy(lastTopDisk, diskname, sizeof(lastTopDisk));
 
          read_sum += read_tmp;
          write_sum += write_tmp;