docs: kernel_abi.py: use --enable-lineno for get_abi.pl

Just like kernel-doc extension, we need to be able to identify
what part of an imported document has issues, as reporting them
as:

	get_abi.pl rest --dir $srctree/Documentation/ABI/obsolete --rst-source:1689: ERROR: Unexpected indentation.

Makes a lot harder for someone to fix.

It should be noticed that it the line which will be reported is
the line where the "What:" definition is, and not the line
with actually has an error.
Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/d6155ab16fb7631f2fa8e7a770eae72f24bf7cc5.1604042072.git.mchehab+huawei@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/sphinx/kernel_abi.py

@@ -36,6 +36,7 @@ import codecs
 import os
 import subprocess
 import sys
+import re
 
 from os import path
 
@@ -93,7 +94,7 @@ class KernelCmd(Directive):
 
         env = doc.settings.env
         cwd = path.dirname(doc.current_source)
-        cmd = "get_abi.pl rest --dir "
+        cmd = "get_abi.pl rest --enable-lineno --dir "
         cmd += self.arguments[0]
 
         srctree = path.abspath(os.environ["srctree"])
@@ -137,7 +138,7 @@ class KernelCmd(Directive):
                               % (self.name, ErrorString(exc)))
         return out
 
-    def nestedParse(self, lines, fname):
+    def nestedParse(self, lines, f):
         content = ViewList()
         node    = nodes.section()
 
@@ -147,8 +148,17 @@ class KernelCmd(Directive):
                 code_block += "\n    " + l
             lines = code_block + "\n\n"
 
-        for c, l in enumerate(lines.split("\n")):
-            content.append(l, fname, c)
+        line_regex = re.compile("^#define LINENO (\S+)\#([0-9]+)$")
+        ln = 0
+
+        for line in lines.split("\n"):
+            match = line_regex.search(line)
+            if match:
+                f = match.group(1)
+                # sphinx counts lines from 0
+                ln = int(match.group(2)) - 1
+            else:
+                content.append(line, f, ln)
 
         buf  = self.state.memo.title_styles, self.state.memo.section_level, self.state.memo.reporter