Merge tag 'docs-4.18' of git://git.lwn.net/linux

Pull documentation updates from Jonathan Corbet:
 "There's been a fair amount of work in the docs tree this time around,
  including:

   - Extensive RST conversions and organizational work in the
     memory-management docs thanks to Mike Rapoport.

   - An update of Documentation/features from Andrea Parri and a script
     to keep it updated.

   - Various LICENSES updates from Thomas, along with a script to check
     SPDX tags.

   - Work to fix dangling references to documentation files; this
     involved a fair number of one-liner comment changes outside of
     Documentation/

  ... and the usual list of documentation improvements, typo fixes, etc"

* tag 'docs-4.18' of git://git.lwn.net/linux: (103 commits)
  Documentation: document hung_task_panic kernel parameter
  docs/admin-guide/mm: add high level concepts overview
  docs/vm: move ksm and transhuge from "user" to "internals" section.
  docs: Use the kerneldoc comments for memalloc_no*()
  doc: document scope NOFS, NOIO APIs
  docs: update kernel versions and dates in tables
  docs/vm: transhuge: split userspace bits to admin-guide/mm/transhuge
  docs/vm: transhuge: minor updates
  docs/vm: transhuge: change sections order
  Documentation: arm: clean up Marvell Berlin family info
  Documentation: gpio: driver: Fix a typo and some odd grammar
  docs: ranoops.rst: fix location of ramoops.txt
  scripts/documentation-file-ref-check: rewrite it in perl with auto-fix mode
  docs: uio-howto.rst: use a code block to solve a warning
  mm, THP, doc: Add document for thp_swpout/thp_swpout_fallback
  w1: w1_io.c: fix a kernel-doc warning
  Documentation/process/posting: wrap text at 80 cols
  docs: admin-guide: add cgroup-v2 documentation
  Revert "Documentation/features/vm: Remove arch support status file for 'pte_special'"
  Documentation: refcount-vs-atomic: Update reference to LKMM doc.
  ...

2 files changed, 397 insertions, 12 deletions

diff --git a/scripts/documentation-file-ref-check b/scripts/documentation-file-ref-check
index bc1659900e89..2520bc14ffac 100755
--- a/scripts/documentation-file-ref-check
+++ b/scripts/documentation-file-ref-check
@@ -1,15 +1,116 @@
-#!/bin/sh
+#!/usr/bin/env perl
+# SPDX-License-Identifier: GPL-2.0
+#
 # Treewide grep for references to files under Documentation, and report
 # non-existing files in stderr.
 
-for f in $(git ls-files); do
-        for ref in $(grep -ho "Documentation/[A-Za-z0-9_.,~/*+-]*" "$f"); do
-                # presume trailing . and , are not part of the name
-                ref=${ref%%[.,]}
-
-                # use ls to handle wildcards
-                if ! ls $ref >/dev/null 2>&1; then
-                        echo "$f: $ref" >&2
-                fi
-        done
-done
+use warnings;
+use strict;
+use Getopt::Long qw(:config no_auto_abbrev);
+
+my $scriptname = $0;
+$scriptname =~ s,.*/([^/]+/),$1,;
+
+# Parse arguments
+my $help = 0;
+my $fix = 0;
+
+GetOptions(
+        'fix' => \$fix,
+        'h|help|usage' => \$help,
+);
+
+if ($help != 0) {
+    print "$scriptname [--help] [--fix-rst]\n";
+    exit -1;
+}
+
+# Step 1: find broken references
+print "Finding broken references. This may take a while...  " if ($fix);
+
+my %broken_ref;
+
+open IN, "git grep 'Documentation/'|"
+     or die "Failed to run git grep";
+while (<IN>) {
+        next if (!m/^([^:]+):(.*)/);
+
+        my $f = $1;
+        my $ln = $2;
+
+        # Makefiles contain nasty expressions to parse docs
+        next if ($f =~ m/Makefile/);
+        # Skip this script
+        next if ($f eq $scriptname);
+
+        if ($ln =~ m,\b(\S*)(Documentation/[A-Za-z0-9\_\.\,\~/\*+-]*),) {
+                my $prefix = $1;
+                my $ref = $2;
+                my $base = $2;
+
+                $ref =~ s/[\,\.]+$//;
+
+                my $fulref = "$prefix$ref";
+
+                $fulref =~ s/^(\<file|ref)://;
+                $fulref =~ s/^[\'\`]+//;
+                $fulref =~ s,^\$\(.*\)/,,;
+                $base =~ s,.*/,,;
+
+                # Remove URL false-positives
+                next if ($fulref =~ m/^http/);
+
+                # Check if exists, evaluating wildcards
+                next if (grep -e, glob("$ref $fulref"));
+
+                if ($fix) {
+                        if (!($ref =~ m/(devicetree|scripts|Kconfig|Kbuild)/)) {
+                                $broken_ref{$ref}++;
+                        }
+                } else {
+                        print STDERR "$f: $fulref\n";
+                }
+        }
+}
+
+exit 0 if (!$fix);
+
+# Step 2: Seek for file name alternatives
+print "Auto-fixing broken references. Please double-check the results\n";
+
+foreach my $ref (keys %broken_ref) {
+        my $new =$ref;
+
+        # get just the basename
+        $new =~ s,.*/,,;
+
+        # Seek for the same name on another place, as it may have been moved
+        my $f="";
+
+        $f = qx(find . -iname $new) if ($new);
+
+        # usual reason for breakage: file renamed to .rst
+        if (!$f) {
+                $new =~ s/\.txt$/.rst/;
+                $f=qx(find . -iname $new) if ($new);
+        }
+
+        my @find = split /\s+/, $f;
+
+        if (!$f) {
+                print STDERR "ERROR: Didn't find a replacement for $ref\n";
+        } elsif (scalar(@find) > 1) {
+                print STDERR "WARNING: Won't auto-replace, as found multiple files close to $ref:\n";
+                foreach my $j (@find) {
+                        $j =~ s,^./,,;
+                        print STDERR "    $j\n";
+                }
+        } else {
+                $f = $find[0];
+                $f =~ s,^./,,;
+                print "INFO: Replacing $ref to $f\n";
+                foreach my $j (qx(git grep -l $ref)) {
+                        qx(sed "s\@$ref\@$f\@g" -i $j);
+                }
+        }
+}
diff --git a/scripts/spdxcheck.py b/scripts/spdxcheck.py
new file mode 100755
index 000000000000..7deaef297f52
--- /dev/null
+++ b/scripts/spdxcheck.py
@@ -0,0 +1,284 @@
+#!/usr/bin/env python
+# SPDX-License-Identifier: GPL-2.0
+# Copyright Thomas Gleixner <tglx@linutronix.de>
+
+from argparse import ArgumentParser
+from ply import lex, yacc
+import traceback
+import sys
+import git
+import re
+import os
+
+class ParserException(Exception):
+    def __init__(self, tok, txt):
+        self.tok = tok
+        self.txt = txt
+
+class SPDXException(Exception):
+    def __init__(self, el, txt):
+        self.el = el
+        self.txt = txt
+
+class SPDXdata(object):
+    def __init__(self):
+        self.license_files = 0
+        self.exception_files = 0
+        self.licenses = [ ]
+        self.exceptions = { }
+
+# Read the spdx data from the LICENSES directory
+def read_spdxdata(repo):
+
+    # The subdirectories of LICENSES in the kernel source
+    license_dirs = [ "preferred", "other", "exceptions" ]
+    lictree = repo.heads.master.commit.tree['LICENSES']
+
+    spdx = SPDXdata()
+
+    for d in license_dirs:
+        for el in lictree[d].traverse():
+            if not os.path.isfile(el.path):
+                continue
+
+            exception = None
+            for l in open(el.path).readlines():
+                if l.startswith('Valid-License-Identifier:'):
+                    lid = l.split(':')[1].strip().upper()
+                    if lid in spdx.licenses:
+                        raise SPDXException(el, 'Duplicate License Identifier: %s' %lid)
+                    else:
+                        spdx.licenses.append(lid)
+
+                elif l.startswith('SPDX-Exception-Identifier:'):
+                    exception = l.split(':')[1].strip().upper()
+                    spdx.exceptions[exception] = []
+
+                elif l.startswith('SPDX-Licenses:'):
+                    for lic in l.split(':')[1].upper().strip().replace(' ', '').replace('\t', '').split(','):
+                        if not lic in spdx.licenses:
+                            raise SPDXException(None, 'Exception %s missing license %s' %(ex, lic))
+                        spdx.exceptions[exception].append(lic)
+
+                elif l.startswith("License-Text:"):
+                    if exception:
+                        if not len(spdx.exceptions[exception]):
+                            raise SPDXException(el, 'Exception %s is missing SPDX-Licenses' %excid)
+                        spdx.exception_files += 1
+                    else:
+                        spdx.license_files += 1
+                    break
+    return spdx
+
+class id_parser(object):
+
+    reserved = [ 'AND', 'OR', 'WITH' ]
+    tokens = [ 'LPAR', 'RPAR', 'ID', 'EXC' ] + reserved
+
+    precedence = ( ('nonassoc', 'AND', 'OR'), )
+
+    t_ignore = ' \t'
+
+    def __init__(self, spdx):
+        self.spdx = spdx
+        self.lasttok = None
+        self.lastid = None
+        self.lexer = lex.lex(module = self, reflags = re.UNICODE)
+        # Initialize the parser. No debug file and no parser rules stored on disk
+        # The rules are small enough to be generated on the fly
+        self.parser = yacc.yacc(module = self, write_tables = False, debug = False)
+        self.lines_checked = 0
+        self.checked = 0
+        self.spdx_valid = 0
+        self.spdx_errors = 0
+        self.curline = 0
+        self.deepest = 0
+
+    # Validate License and Exception IDs
+    def validate(self, tok):
+        id = tok.value.upper()
+        if tok.type == 'ID':
+            if not id in self.spdx.licenses:
+                raise ParserException(tok, 'Invalid License ID')
+            self.lastid = id
+        elif tok.type == 'EXC':
+            if not self.spdx.exceptions.has_key(id):
+                raise ParserException(tok, 'Invalid Exception ID')
+            if self.lastid not in self.spdx.exceptions[id]:
+                raise ParserException(tok, 'Exception not valid for license %s' %self.lastid)
+            self.lastid = None
+        elif tok.type != 'WITH':
+            self.lastid = None
+
+    # Lexer functions
+    def t_RPAR(self, tok):
+        r'\)'
+        self.lasttok = tok.type
+        return tok
+
+    def t_LPAR(self, tok):
+        r'\('
+        self.lasttok = tok.type
+        return tok
+
+    def t_ID(self, tok):
+        r'[A-Za-z.0-9\-+]+'
+
+        if self.lasttok == 'EXC':
+            print(tok)
+            raise ParserException(tok, 'Missing parentheses')
+
+        tok.value = tok.value.strip()
+        val = tok.value.upper()
+
+        if val in self.reserved:
+            tok.type = val
+        elif self.lasttok == 'WITH':
+            tok.type = 'EXC'
+
+        self.lasttok = tok.type
+        self.validate(tok)
+        return tok
+
+    def t_error(self, tok):
+        raise ParserException(tok, 'Invalid token')
+
+    def p_expr(self, p):
+        '''expr : ID
+                | ID WITH EXC
+                | expr AND expr
+                | expr OR expr
+                | LPAR expr RPAR'''
+        pass
+
+    def p_error(self, p):
+        if not p:
+            raise ParserException(None, 'Unfinished license expression')
+        else:
+            raise ParserException(p, 'Syntax error')
+
+    def parse(self, expr):
+        self.lasttok = None
+        self.lastid = None
+        self.parser.parse(expr, lexer = self.lexer)
+
+    def parse_lines(self, fd, maxlines, fname):
+        self.checked += 1
+        self.curline = 0
+        try:
+            for line in fd:
+                self.curline += 1
+                if self.curline > maxlines:
+                    break
+                self.lines_checked += 1
+                if line.find("SPDX-License-Identifier:") < 0:
+                    continue
+                expr = line.split(':')[1].replace('*/', '').strip()
+                self.parse(expr)
+                self.spdx_valid += 1
+                #
+                # Should we check for more SPDX ids in the same file and
+                # complain if there are any?
+                #
+                break
+
+        except ParserException as pe:
+            if pe.tok:
+                col = line.find(expr) + pe.tok.lexpos
+                tok = pe.tok.value
+                sys.stdout.write('%s: %d:%d %s: %s\n' %(fname, self.curline, col, pe.txt, tok))
+            else:
+                sys.stdout.write('%s: %d:0 %s\n' %(fname, self.curline, col, pe.txt))
+            self.spdx_errors += 1
+
+def scan_git_tree(tree):
+    for el in tree.traverse():
+        # Exclude stuff which would make pointless noise
+        # FIXME: Put this somewhere more sensible
+        if el.path.startswith("LICENSES"):
+            continue
+        if el.path.find("license-rules.rst") >= 0:
+            continue
+        if el.path == 'scripts/checkpatch.pl':
+            continue
+        if not os.path.isfile(el.path):
+            continue
+        parser.parse_lines(open(el.path), args.maxlines, el.path)
+
+def scan_git_subtree(tree, path):
+    for p in path.strip('/').split('/'):
+        tree = tree[p]
+    scan_git_tree(tree)
+
+if __name__ == '__main__':
+
+    ap = ArgumentParser(description='SPDX expression checker')
+    ap.add_argument('path', nargs='*', help='Check path or file. If not given full git tree scan. For stdin use "-"')
+    ap.add_argument('-m', '--maxlines', type=int, default=15,
+                    help='Maximum number of lines to scan in a file. Default 15')
+    ap.add_argument('-v', '--verbose', action='store_true', help='Verbose statistics output')
+    args = ap.parse_args()
+
+    # Sanity check path arguments
+    if '-' in args.path and len(args.path) > 1:
+        sys.stderr.write('stdin input "-" must be the only path argument\n')
+        sys.exit(1)
+
+    try:
+        # Use git to get the valid license expressions
+        repo = git.Repo(os.getcwd())
+        assert not repo.bare
+
+        # Initialize SPDX data
+        spdx = read_spdxdata(repo)
+
+        # Initilize the parser
+        parser = id_parser(spdx)
+
+    except SPDXException as se:
+        if se.el:
+            sys.stderr.write('%s: %s\n' %(se.el.path, se.txt))
+        else:
+            sys.stderr.write('%s\n' %se.txt)
+        sys.exit(1)
+
+    except Exception as ex:
+        sys.stderr.write('FAIL: %s\n' %ex)
+        sys.stderr.write('%s\n' %traceback.format_exc())
+        sys.exit(1)
+
+    try:
+        if len(args.path) and args.path[0] == '-':
+            parser.parse_lines(sys.stdin, args.maxlines, '-')
+        else:
+            if args.path:
+                for p in args.path:
+                    if os.path.isfile(p):
+                        parser.parse_lines(open(p), args.maxlines, p)
+                    elif os.path.isdir(p):
+                        scan_git_subtree(repo.head.reference.commit.tree, p)
+                    else:
+                        sys.stderr.write('path %s does not exist\n' %p)
+                        sys.exit(1)
+            else:
+                # Full git tree scan
+                scan_git_tree(repo.head.commit.tree)
+
+            if args.verbose:
+                sys.stderr.write('\n')
+                sys.stderr.write('License files:     %12d\n' %spdx.license_files)
+                sys.stderr.write('Exception files:   %12d\n' %spdx.exception_files)
+                sys.stderr.write('License IDs        %12d\n' %len(spdx.licenses))
+                sys.stderr.write('Exception IDs      %12d\n' %len(spdx.exceptions))
+                sys.stderr.write('\n')
+                sys.stderr.write('Files checked:     %12d\n' %parser.checked)
+                sys.stderr.write('Lines checked:     %12d\n' %parser.lines_checked)
+                sys.stderr.write('Files with SPDX:   %12d\n' %parser.spdx_valid)
+                sys.stderr.write('Files with errors: %12d\n' %parser.spdx_errors)
+
+            sys.exit(0)
+
+    except Exception as ex:
+        sys.stderr.write('FAIL: %s\n' %ex)
+        sys.stderr.write('%s\n' %traceback.format_exc())
+        sys.exit(1)