ktest.pl: Add new PATCHCHECK_SKIP option to skip testing individual commits

When testing a series of commits that also includes changes to the Linux
tools directory, it is useless to test the changes in tools as they may
not affect the kernel itself. Doing tests on the kernel for changes that
do not affect the kernel is a waste of time.

Add a PATCHCHECK_SKIP that takes a series of shas that will be skipped
while doing the individual commit tests.

For example, the runtime verification may have a series of commits like:

$ git log --abbrev-commit --pretty=oneline fac5493~1..HEAD
3d3800b rv: Remove rv_reactor's reference counter
3d3c376 rv: Merge struct rv_reactor_def into struct rv_reactor
24cbfe1 rv: Merge struct rv_monitor_def into struct rv_monitor
b0c08dd rv: Remove unused field in struct rv_monitor_def
58d5f0d (debiantesting-x86-64/trace/rv/core) rv: Return init error when registering monitors
560473f verification/rvgen: Organise Kconfig entries for nested monitors
9efcf59 tools/dot2c: Fix generated files going over 100 column limit
1160cca tools/rv: Stop gracefully also on SIGTERM
f60227f tools/rv: Do not skip idle in trace
f3735df verification/rvgen: Do not generate unused variables
6fb37c2 verification/rvgen: Generate each variable definition only once
8cfcf9b verification/rvgen: Support the 'next' operator
fac5493 rv: Allow to configure the number of per-task monitor

Where the first commit touches the kernel followed by a series of commits
that do not, and ends with commits that do. Instead of having to add
multiple patchcheck tests to handle the gaps, just include the commits
that should not be tested:

$ git log --abbrev-commit --pretty=oneline fac5493~1..HEAD |
  grep -e verification -e tools/ | cut -d' ' -f1 |
  while read a ; do echo -n "$a "; done
560473f 9efcf59 1160cca f60227f f3735df 6fb37c2 8cfcf9b

Then set PATCHCHECK_SKIP to that, and those commits will be skipped.

 PATCHCHECK_SKIP = 560473f 9efcf59 1160cca f60227f f3735df 6fb37c2 8cfcf9b

Cc: John 'Warthog9' Hawley <warthog9@kernel.org>
Cc: Dhaval Giani <dhaval.giani@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://lore.kernel.org/20250725112153.1dd06b84@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

Author: rostedt

tools/testing/ktest/ktest.pl

@@ -218,6 +218,7 @@
 my $patchcheck_start;
 my $patchcheck_cherry;
 my $patchcheck_end;
+my $patchcheck_skip;
 
 my $build_time;
 my $install_time;
@@ -382,6 +383,7 @@
     "PATCHCHECK_START"		=> \$patchcheck_start,
     "PATCHCHECK_CHERRY"		=> \$patchcheck_cherry,
     "PATCHCHECK_END"		=> \$patchcheck_end,
+    "PATCHCHECK_SKIP"		=> \$patchcheck_skip,
 );
 
 # Options may be used by other options, record them.
@@ -3537,11 +3539,37 @@ sub patchcheck {
 	@list = reverse @list;
     }
 
+    my %skip_list;
+    my $will_skip = 0;
+
+    if (defined($patchcheck_skip)) {
+	foreach my $s (split /\s+/, $patchcheck_skip) {
+	    $s = `git log --pretty=oneline $s~1..$s`;
+	    $s =~ s/^(\S+).*/$1/;
+	    chomp $s;
+	    $skip_list{$s} = 1;
+	    $will_skip++;
+	}
+    }
+
     doprint("Going to test the following commits:\n");
     foreach my $l (@list) {
+	my $sha1 = $l;
+	$sha1 =~ s/^([[:xdigit:]]+).*/$1/;
+	next if (defined($skip_list{$sha1}));
 	doprint "$l\n";
     }
 
+    if ($will_skip) {
+	doprint("\nSkipping the following commits:\n");
+	foreach my $l (@list) {
+	    my $sha1 = $l;
+	    $sha1 =~ s/^([[:xdigit:]]+).*/$1/;
+	    next if (!defined($skip_list{$sha1}));
+	    doprint "$l\n";
+	}
+    }
+
     my $save_clean = $noclean;
     my %ignored_warnings;
 
@@ -3556,6 +3584,11 @@ sub patchcheck {
 	my $sha1 = $item;
 	$sha1 =~ s/^([[:xdigit:]]+).*/$1/;
 
+	if (defined($skip_list{$sha1})) {
+	    doprint "\nSkipping \"$item\"\n\n";
+	    next;
+	}
+
 	doprint "\nProcessing commit \"$item\"\n\n";
 
 	run_command "git checkout $sha1" or

tools/testing/ktest/sample.conf

@@ -1017,6 +1017,8 @@
 #      Note, PATCHCHECK_CHERRY requires PATCHCHECK_END to be defined.
 #      (default 0)
 #
+#  PATCHCHECK_SKIP is an optional list of shas to skip testing
+#
 #  PATCHCHECK_TYPE is required and is the type of test to run:
 #      build, boot, test.
 #