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authorDwaipayan Ray <dwaipayanray1@gmail.com>2020-12-15 20:45:15 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-12-15 22:46:17 -0800
commit70eb2275ff8e0b4cafe67176674d580c987c071d (patch)
tree2e5107d68fa302b6831300b85474c164aef25c06 /scripts/checkpatch.pl
parent831242ab8dffab4cf2f89c597d5902ac86caeefe (diff)
checkpatch: add warning for unnecessary use of %h[xudi] and %hh[xudi]
Modifiers %h and %hh should never be used. Commit cbacb5ab0aa0 ("docs: printk-formats: Stop encouraging use of unnecessary %h[xudi] and %hh[xudi]") specifies that: "Standard integer promotion is already done and %hx and %hhx is useless so do not encourage the use of %hh[xudi] or %h[xudi]." "The "h" and "hh" things should never be used. The only reason for them being used if you have an "int", but you want to print it out as a "char" (and honestly, that is a really bad reason, you'd be better off just using a proper cast to make the code more obvious)." Add a new check to emit a warning on finding an unneeded use of %h or %hh modifier. Also add a fix option to the check. Link: https://lore.kernel.org/lkml/4910042649a4f3ab22fac93191b8c1fa0a2e17c3.camel@perches.com/ Link: https://lkml.kernel.org/r/20201128200046.78739-1-dwaipayanray1@gmail.com Signed-off-by: Dwaipayan Ray <dwaipayanray1@gmail.com> Suggested-by: Joe Perches <joe@perches.com> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Acked-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'scripts/checkpatch.pl')
-rwxr-xr-xscripts/checkpatch.pl22
1 files changed, 22 insertions, 0 deletions
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index d7616a6f1436..2716b9bfc0c2 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -6102,6 +6102,28 @@ sub process {
"Avoid logging continuation uses where feasible\n" . $herecurr);
}
+# check for unnecessary use of %h[xudi] and %hh[xudi] in logging functions
+ if (defined $stat &&
+ $line =~ /\b$logFunctions\s*\(/ &&
+ index($stat, '"') >= 0) {
+ my $lc = $stat =~ tr@\n@@;
+ $lc = $lc + $linenr;
+ my $stat_real = get_stat_real($linenr, $lc);
+ pos($stat_real) = index($stat_real, '"');
+ while ($stat_real =~ /[^\"%]*(%[\#\d\.\*\-]*(h+)[idux])/g) {
+ my $pspec = $1;
+ my $h = $2;
+ my $lineoff = substr($stat_real, 0, $-[1]) =~ tr@\n@@;
+ if (WARN("UNNECESSARY_MODIFIER",
+ "Integer promotion: Using '$h' in '$pspec' is unnecessary\n" . "$here\n$stat_real\n") &&
+ $fix && $fixed[$fixlinenr + $lineoff] =~ /^\+/) {
+ my $nspec = $pspec;
+ $nspec =~ s/h//g;
+ $fixed[$fixlinenr + $lineoff] =~ s/\Q$pspec\E/$nspec/;
+ }
+ }
+ }
+
# check for mask then right shift without a parentheses
if ($perl_version_ok &&
$line =~ /$LvalOrFunc\s*\&\s*($LvalOrFunc)\s*>>/ &&