@@ -74,6 +74,8 @@ my $git_command ='export LANGUAGE=en_US.UTF-8; git';
my $tabsize = 8;
my ${CONFIG_} = "CONFIG_";
+my %maybe_linker_symbol; # for externs in c exceptions, when seen in *vmlinux.lds.h
+
sub help {
my ($exitcode) = @_;
@@ -6051,6 +6053,9 @@ sub process {
# check for line continuations outside of #defines, preprocessor #, and asm
+ } elsif ($realfile =~ m@/vmlinux.lds.h$@) {
+ $line =~ s/(\w+)/$maybe_linker_symbol{$1}++/ge;
+ #print "REAL: $realfile\nln: $line\nkeys:", sort keys %maybe_linker_symbol;
} else {
if ($prevline !~ /^..*\\$/ &&
$line !~ /^\+\s*\#.*\\$/ && # preprocessor
@@ -7107,6 +7112,21 @@ sub process {
"arguments for function declarations should follow identifier\n" . $herecurr);
}
+ } elsif ($realfile =~ /\.c$/ && defined $stat &&
+ $stat =~ /^\+extern struct\s+(\w+)\s+(\w+)\[\];/)
+ {
+ my ($st_type, $st_name) = ($1, $2);
+
+ for my $s (keys %maybe_linker_symbol) {
+ #print "Linker symbol? $st_name : $s\n";
+ goto LIKELY_LINKER_SYMBOL
+ if $st_name =~ /$s/;
+ }
+ WARN("AVOID_EXTERNS",
+ "found a file-scoped extern type:$st_type name:$st_name in .c file\n"
+ . "is this a linker symbol ?\n" . $herecurr);
+ LIKELY_LINKER_SYMBOL:
+
} elsif ($realfile =~ /\.c$/ && defined $stat &&
$stat =~ /^.\s*extern\s+/)
{
"externs should be avoided in .c files" needs an exception for linker symbols, like those that mark the start, stop of many kernel sections. Since code already checks REALNAME to avoid linker-scripts entirely, add a new else-if block to look at them instead. As a simple heuristic, treat all words (in the patch-line) as possible symbols, and save them to screen the WARN quoted above. For my test case, this included BOUNDED_BY (a macro), which is extra, but not troublesome. Where the WARN is issued, precede it with an else-if block to catch one common extern-in-c use case: "extern struct foo bar[]". Here we can at least issue a softer warning, after checking for a match with a maybe-linker-symbol parsed earlier from the patch. Though heuristic, it worked for my test-case, allowing both (start|stop)$symbol's, matched by $symbol, it wasn't thrown by noise (BOUNDED_BY) in the maybe-linker-symbols. NB: git diff ordering dependence on vmlinux.lds.h before c files ? Cc: apw@canonical.com Cc: joe@perches.com Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- scripts/checkpatch.pl | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+)