[PATCH] io_uring: use blk_queue_nowait() to check if NOWAIT supported

[Jeffle Xu <jefflexu@linux.alibaba.com>]

commit 021a24460dc2 ("block: add QUEUE_FLAG_NOWAIT") add a new helper
function blk_queue_nowait() to check if the bdev supports handling of
REQ_NOWAIT or not. Since then bio-based dm device can also support
REQ_NOWAIT, and currently only dm-linear supports that since
commit 6abc49468eea ("dm: add support for REQ_NOWAIT and enable it for
linear target").

Fixes: 4503b7676a2e ("io_uring: catch -EIO from buffered issue request failure")
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
---
 fs/io_uring.c         |   2 +-
 scripts/checkpatch.pl | 313 ++++++++++++------------------------------
 2 files changed, 85 insertions(+), 230 deletions(-)

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 2e1dc354cd08..7d8615df3c01 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2601,7 +2601,7 @@ static struct file *__io_file_get(struct io_submit_state *state, int fd)
 static bool io_bdev_nowait(struct block_device *bdev)
 {
 #ifdef CONFIG_BLOCK
-	return !bdev || queue_is_mq(bdev_get_queue(bdev));
+	return !bdev || blk_queue_nowait(bdev_get_queue(bdev));
 #else
 	return true;
 #endif
diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 4223a9ac7059..4c820607540b 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -59,13 +59,12 @@ my $spelling_file = "$D/spelling.txt";
 my $codespell = 0;
 my $codespellfile = "/usr/share/codespell/dictionary.txt";
 my $conststructsfile = "$D/const_structs.checkpatch";
-my $typedefsfile;
+my $typedefsfile = "";
 my $color = "auto";
 my $allow_c99_comments = 1; # Can be overridden by --ignore C99_COMMENT_TOLERANCE
 # git output parsing needs US English output, so first set backtick child process LANGUAGE
 my $git_command ='export LANGUAGE=en_US.UTF-8; git';
 my $tabsize = 8;
-my ${CONFIG_} = "CONFIG_";
 
 sub help {
 	my ($exitcode) = @_;
@@ -128,8 +127,6 @@ Options:
   --typedefsfile             Read additional types from this file
   --color[=WHEN]             Use colors 'always', 'never', or only when output
                              is a terminal ('auto'). Default is 'auto'.
-  --kconfig-prefix=WORD      use WORD as a prefix for Kconfig symbols (default
-                             ${CONFIG_})
   -h, --help, --version      display this help and exit
 
 When FILE is - read standard input.
@@ -238,7 +235,6 @@ GetOptions(
 	'color=s'	=> \$color,
 	'no-color'	=> \$color,	#keep old behaviors of -nocolor
 	'nocolor'	=> \$color,	#keep old behaviors of -nocolor
-	'kconfig-prefix=s'	=> \${CONFIG_},
 	'h|help'	=> \$help,
 	'version'	=> \$help
 ) or help(1);
@@ -592,8 +588,6 @@ our @mode_permission_funcs = (
 	["__ATTR", 2],
 );
 
-my $word_pattern = '\b[A-Z]?[a-z]{2,}\b';
-
 #Create a search pattern for all these functions to speed up a loop below
 our $mode_perms_search = "";
 foreach my $entry (@mode_permission_funcs) {
@@ -762,7 +756,7 @@ sub read_words {
 				next;
 			}
 
-			$$wordsRef .= '|' if (defined $$wordsRef);
+			$$wordsRef .= '|' if ($$wordsRef ne "");
 			$$wordsRef .= $line;
 		}
 		close($file);
@@ -772,18 +766,16 @@ sub read_words {
 	return 0;
 }
 
-my $const_structs;
-if (show_type("CONST_STRUCT")) {
-	read_words(\$const_structs, $conststructsfile)
-	    or warn "No structs that should be const will be found - file '$conststructsfile': $!\n";
-}
+my $const_structs = "";
+read_words(\$const_structs, $conststructsfile)
+    or warn "No structs that should be const will be found - file '$conststructsfile': $!\n";
 
-if (defined($typedefsfile)) {
-	my $typeOtherTypedefs;
+my $typeOtherTypedefs = "";
+if (length($typedefsfile)) {
 	read_words(\$typeOtherTypedefs, $typedefsfile)
 	    or warn "No additional types will be considered - file '$typedefsfile': $!\n";
-	$typeTypedefs .= '|' . $typeOtherTypedefs if (defined $typeOtherTypedefs);
 }
+$typeTypedefs .= '|' . $typeOtherTypedefs if ($typeOtherTypedefs ne "");
 
 sub build_types {
 	my $mods = "(?x:  \n" . join("|\n  ", (@modifierList, @modifierListFile)) . "\n)";
@@ -848,6 +840,7 @@ our $FuncArg = qr{$Typecast{0,1}($LvalOrFunc|$Constant|$String)};
 our $declaration_macros = qr{(?x:
 	(?:$Storage\s+)?(?:[A-Z_][A-Z0-9]*_){0,2}(?:DEFINE|DECLARE)(?:_[A-Z0-9]+){1,6}\s*\(|
 	(?:$Storage\s+)?[HLP]?LIST_HEAD\s*\(|
+	(?:$Storage\s+)?${Type}\s+uninitialized_var\s*\(|
 	(?:SKCIPHER_REQUEST|SHASH_DESC|AHASH_REQUEST)_ON_STACK\s*\(
 )};
 
@@ -974,16 +967,6 @@ sub seed_camelcase_includes {
 	}
 }
 
-sub git_is_single_file {
-	my ($filename) = @_;
-
-	return 0 if ((which("git") eq "") || !(-e "$gitroot"));
-
-	my $output = `${git_command} ls-files -- $filename 2>/dev/null`;
-	my $count = $output =~ tr/\n//;
-	return $count eq 1 && $output =~ m{^${filename}$};
-}
-
 sub git_commit_info {
 	my ($commit, $id, $desc) = @_;
 
@@ -1057,9 +1040,6 @@ my $vname;
 $allow_c99_comments = !defined $ignore_type{"C99_COMMENT_TOLERANCE"};
 for my $filename (@ARGV) {
 	my $FILE;
-	my $is_git_file = git_is_single_file($filename);
-	my $oldfile = $file;
-	$file = 1 if ($is_git_file);
 	if ($git) {
 		open($FILE, '-|', "git format-patch -M --stdout -1 $filename") ||
 			die "$P: $filename: git format-patch failed - $!\n";
@@ -1104,7 +1084,6 @@ for my $filename (@ARGV) {
 	@modifierListFile = ();
 	@typeListFile = ();
 	build_types();
-	$file = $oldfile if ($is_git_file);
 }
 
 if (!$quiet) {
@@ -1181,10 +1160,10 @@ sub parse_email {
 		}
 	}
 
-	$comment = trim($comment);
 	$name = trim($name);
 	$name =~ s/^\"|\"$//g;
-	if ($name =~ s/(\s*\([^\)]+\))\s*//) {
+	$name =~ s/(\s*\([^\)]+\))\s*//;
+	if (defined($1)) {
 		$name_comment = trim($1);
 	}
 	$address = trim($address);
@@ -1199,12 +1178,10 @@ sub parse_email {
 }
 
 sub format_email {
-	my ($name, $name_comment, $address, $comment) = @_;
+	my ($name, $address) = @_;
 
 	my $formatted_email;
 
-	$name_comment = trim($name_comment);
-	$comment = trim($comment);
 	$name = trim($name);
 	$name =~ s/^\"|\"$//g;
 	$address = trim($address);
@@ -1217,9 +1194,9 @@ sub format_email {
 	if ("$name" eq "") {
 		$formatted_email = "$address";
 	} else {
-		$formatted_email = "$name$name_comment <$address>";
+		$formatted_email = "$name <$address>";
 	}
-	$formatted_email .= "$comment";
+
 	return $formatted_email;
 }
 
@@ -1227,23 +1204,17 @@ sub reformat_email {
 	my ($email) = @_;
 
 	my ($email_name, $name_comment, $email_address, $comment) = parse_email($email);
-	return format_email($email_name, $name_comment, $email_address, $comment);
+	return format_email($email_name, $email_address);
 }
 
 sub same_email_addresses {
-	my ($email1, $email2, $match_comment) = @_;
+	my ($email1, $email2) = @_;
 
 	my ($email1_name, $name1_comment, $email1_address, $comment1) = parse_email($email1);
 	my ($email2_name, $name2_comment, $email2_address, $comment2) = parse_email($email2);
 
-	if ($match_comment != 1) {
-		return $email1_name eq $email2_name &&
-		       $email1_address eq $email2_address;
-	}
 	return $email1_name eq $email2_name &&
-	       $email1_address eq $email2_address &&
-	       $name1_comment eq $name2_comment &&
-	       $comment1 eq $comment2;
+	       $email1_address eq $email2_address;
 }
 
 sub which {
@@ -2373,7 +2344,6 @@ sub process {
 	my $signoff = 0;
 	my $author = '';
 	my $authorsignoff = 0;
-	my $author_sob = '';
 	my $is_patch = 0;
 	my $is_binding_patch = -1;
 	my $in_header_lines = $file ? 0 : 1;
@@ -2666,8 +2636,8 @@ sub process {
 
 # Check if the commit log has what seems like a diff which can confuse patch
 		if ($in_commit_log && !$commit_log_has_diff &&
-		    (($line =~ m@^\s+diff\b.*a/([\w/]+)@ &&
-		      $line =~ m@^\s+diff\b.*a/[\w/]+\s+b/$1\b@) ||
+		    (($line =~ m@^\s+diff\b.*a/[\w/]+@ &&
+		      $line =~ m@^\s+diff\b.*a/([\w/]+)\s+b/$1\b@) ||
 		     $line =~ m@^\s*(?:\-\-\-\s+a/|\+\+\+\s+b/)@ ||
 		     $line =~ m/^\s*\@\@ \-\d+,\d+ \+\d+,\d+ \@\@/)) {
 			ERROR("DIFF_IN_COMMIT_MSG",
@@ -2688,10 +2658,6 @@ sub process {
 # Check the patch for a From:
 		if (decode("MIME-Header", $line) =~ /^From:\s*(.*)/) {
 			$author = $1;
-			my $curline = $linenr;
-			while(defined($rawlines[$curline]) && ($rawlines[$curline++] =~ /^[ \t]\s*(.*)/)) {
-				$author .= $1;
-			}
 			$author = encode("utf8", $author) if ($line =~ /=\?utf-8\?/i);
 			$author =~ s/"//g;
 			$author = reformat_email($author);
@@ -2701,37 +2667,9 @@ sub process {
 		if ($line =~ /^\s*signed-off-by:\s*(.*)/i) {
 			$signoff++;
 			$in_commit_log = 0;
-			if ($author ne ''  && $authorsignoff != 1) {
-				if (same_email_addresses($1, $author, 1)) {
+			if ($author ne '') {
+				if (same_email_addresses($1, $author)) {
 					$authorsignoff = 1;
-				} else {
-					my $ctx = $1;
-					my ($email_name, $email_comment, $email_address, $comment1) = parse_email($ctx);
-					my ($author_name, $author_comment, $author_address, $comment2) = parse_email($author);
-
-					if ($email_address eq $author_address && $email_name eq $author_name) {
-						$author_sob = $ctx;
-						$authorsignoff = 2;
-					} elsif ($email_address eq $author_address) {
-						$author_sob = $ctx;
-						$authorsignoff = 3;
-					} elsif ($email_name eq $author_name) {
-						$author_sob = $ctx;
-						$authorsignoff = 4;
-
-						my $address1 = $email_address;
-						my $address2 = $author_address;
-
-						if ($address1 =~ /(\S+)\+\S+(\@.*)/) {
-							$address1 = "$1$2";
-						}
-						if ($address2 =~ /(\S+)\+\S+(\@.*)/) {
-							$address2 = "$1$2";
-						}
-						if ($address1 eq $address2) {
-							$authorsignoff = 5;
-						}
-					}
 				}
 			}
 		}
@@ -2788,7 +2726,7 @@ sub process {
 			}
 
 			my ($email_name, $name_comment, $email_address, $comment) = parse_email($email);
-			my $suggested_email = format_email(($email_name, $name_comment, $email_address, $comment));
+			my $suggested_email = format_email(($email_name, $email_address));
 			if ($suggested_email eq "") {
 				ERROR("BAD_SIGN_OFF",
 				      "Unrecognized email address: '$email'\n" . $herecurr);
@@ -2798,9 +2736,9 @@ sub process {
 				$dequoted =~ s/" </ </;
 				# Don't force email to have quotes
 				# Allow just an angle bracketed address
-				if (!same_email_addresses($email, $suggested_email, 0)) {
+				if (!same_email_addresses($email, $suggested_email)) {
 					WARN("BAD_SIGN_OFF",
-					     "email address '$email' might be better as '$suggested_email'\n" . $herecurr);
+					     "email address '$email' might be better as '$suggested_email$comment'\n" . $herecurr);
 				}
 			}
 
@@ -3046,42 +2984,6 @@ sub process {
 			}
 		}
 
-# check for repeated words separated by a single space
-		if ($rawline =~ /^\+/ || $in_commit_log) {
-			while ($rawline =~ /\b($word_pattern) (?=($word_pattern))/g) {
-
-				my $first = $1;
-				my $second = $2;
-
-				if ($first =~ /(?:struct|union|enum)/) {
-					pos($rawline) += length($first) + length($second) + 1;
-					next;
-				}
-
-				next if ($first ne $second);
-				next if ($first eq 'long');
-
-				if (WARN("REPEATED_WORD",
-					 "Possible repeated word: '$first'\n" . $herecurr) &&
-				    $fix) {
-					$fixed[$fixlinenr] =~ s/\b$first $second\b/$first/;
-				}
-			}
-
-			# if it's a repeated word on consecutive lines in a comment block
-			if ($prevline =~ /$;+\s*$/ &&
-			    $prevrawline =~ /($word_pattern)\s*$/) {
-				my $last_word = $1;
-				if ($rawline =~ /^\+\s*\*\s*$last_word /) {
-					if (WARN("REPEATED_WORD",
-						 "Possible repeated word: '$last_word'\n" . $hereprev) &&
-					    $fix) {
-						$fixed[$fixlinenr] =~ s/(\+\s*\*\s*)$last_word /$1/;
-					}
-				}
-			}
-		}
-
 # ignore non-hunk lines and lines being removed
 		next if (!$hunk_line || $line =~ /^-/);
 
@@ -3140,7 +3042,11 @@ sub process {
 
 				if ($lines[$ln - 1] =~ /^\+\s*(?:bool|tristate|prompt)\s*["']/) {
 					$is_start = 1;
-				} elsif ($lines[$ln - 1] =~ /^\+\s*(?:---)?help(?:---)?$/) {
+				} elsif ($lines[$ln - 1] =~ /^\+\s*(?:help|---help---)\s*$/) {
+					if ($lines[$ln - 1] =~ "---help---") {
+						WARN("CONFIG_DESCRIPTION",
+						     "prefer 'help' over '---help---' for new help texts\n" . $herecurr);
+					}
 					$length = -1;
 				}
 
@@ -3308,12 +3214,6 @@ sub process {
 			}
 		}
 
-# check for embedded filenames
-		if ($rawline =~ /^\+.*\Q$realfile\E/) {
-			WARN("EMBEDDED_FILENAME",
-			     "It's generally not useful to have the filename in the file\n" . $herecurr);
-		}
-
 # check we are in a valid source file if not then ignore this hunk
 		next if ($realfile !~ /\.(h|c|s|S|sh|dtsi|dts)$/);
 
@@ -3501,7 +3401,7 @@ sub process {
 		if ($realfile =~ m@^(drivers/net/|net/)@ &&
 		    $prevrawline =~ /^\+[ \t]*\/\*[ \t]*$/ &&
 		    $rawline =~ /^\+[ \t]*\*/ &&
-		    $realline > 3) { # Do not warn about the initial copyright comment block after SPDX-License-Identifier
+		    $realline > 2) {
 			WARN("NETWORKING_BLOCK_COMMENT_STYLE",
 			     "networking block comments don't use an empty /* line, use /* Comment...\n" . $hereprev);
 		}
@@ -3960,17 +3860,6 @@ sub process {
 #ignore lines not being added
 		next if ($line =~ /^[^\+]/);
 
-# check for self assignments used to avoid compiler warnings
-# e.g.:	int foo = foo, *bar = NULL;
-#	struct foo bar = *(&(bar));
-		if ($line =~ /^\+\s*(?:$Declare)?([A-Za-z_][A-Za-z\d_]*)\s*=/) {
-			my $var = $1;
-			if ($line =~ /^\+\s*(?:$Declare)?$var\s*=\s*(?:$var|\*\s*\(?\s*&\s*\(?\s*$var\s*\)?\s*\)?)\s*[;,]/) {
-				WARN("SELF_ASSIGNMENT",
-				     "Do not use self-assignments to avoid compiler warnings\n" . $herecurr);
-			}
-		}
-
 # check for dereferences that span multiple lines
 		if ($prevline =~ /^\+.*$Lval\s*(?:\.|->)\s*$/ &&
 		    $line =~ /^\+\s*(?!\#\s*(?!define\s+|if))\s*$Lval/) {
@@ -4346,12 +4235,6 @@ sub process {
 			     "Prefer dev_$level(... to dev_printk(KERN_$orig, ...\n" . $herecurr);
 		}
 
-# trace_printk should not be used in production code.
-		if ($line =~ /\b(trace_printk|trace_puts|ftrace_vprintk)\s*\(/) {
-			WARN("TRACE_PRINTK",
-			     "Do not use $1() in production code (this can be ignored if built only with a debug config option)\n" . $herecurr);
-		}
-
 # ENOSYS means "bad syscall nr" and nothing else.  This will have a small
 # number of false positives, but assembly files are not checked, so at
 # least the arch entry code will not trigger this warning.
@@ -5018,17 +4901,6 @@ sub process {
 			}
 		}
 
-# check if a statement with a comma should be two statements like:
-#	foo = bar(),	/* comma should be semicolon */
-#	bar = baz();
-		if (defined($stat) &&
-		    $stat =~ /^\+\s*(?:$Lval\s*$Assignment\s*)?$FuncArg\s*,\s*(?:$Lval\s*$Assignment\s*)?$FuncArg\s*;\s*$/) {
-			my $cnt = statement_rawlines($stat);
-			my $herectx = get_stat_here($linenr, $cnt, $here);
-			WARN("SUSPECT_COMMA_SEMICOLON",
-			     "Possible comma where semicolon could be used\n" . $herectx);
-		}
-
 # return is not a function
 		if (defined($stat) && $stat =~ /^.\s*return(\s*)\(/s) {
 			my $spacing = $1;
@@ -5149,30 +5021,8 @@ sub process {
 			my ($s, $c) = ($stat, $cond);
 
 			if ($c =~ /\bif\s*\(.*[^<>!=]=[^=].*/s) {
-				if (ERROR("ASSIGN_IN_IF",
-					  "do not use assignment in if condition\n" . $herecurr) &&
-				    $fix && $perl_version_ok) {
-					if ($rawline =~ /^\+(\s+)if\s*\(\s*(\!)?\s*\(\s*(($Lval)\s*=\s*$LvalOrFunc)\s*\)\s*(?:($Compare)\s*($FuncArg))?\s*\)\s*(\{)?\s*$/) {
-						my $space = $1;
-						my $not = $2;
-						my $statement = $3;
-						my $assigned = $4;
-						my $test = $8;
-						my $against = $9;
-						my $brace = $15;
-						fix_delete_line($fixlinenr, $rawline);
-						fix_insert_line($fixlinenr, "$space$statement;");
-						my $newline = "${space}if (";
-						$newline .= '!' if defined($not);
-						$newline .= '(' if (defined $not && defined($test) && defined($against));
-						$newline .= "$assigned";
-						$newline .= " $test $against" if (defined($test) && defined($against));
-						$newline .= ')' if (defined $not && defined($test) && defined($against));
-						$newline .= ')';
-						$newline .= " {" if (defined($brace));
-						fix_insert_line($fixlinenr + 1, $newline);
-					}
-				}
+				ERROR("ASSIGN_IN_IF",
+				      "do not use assignment in if condition\n" . $herecurr);
 			}
 
 			# Find out what is on the end of the line after the
@@ -5388,9 +5238,9 @@ sub process {
 			$dstat =~ s/\s*$//s;
 
 			# Flatten any parentheses and braces
-			while ($dstat =~ s/\([^\(\)]*\)/1u/ ||
-			       $dstat =~ s/\{[^\{\}]*\}/1u/ ||
-			       $dstat =~ s/.\[[^\[\]]*\]/1u/)
+			while ($dstat =~ s/\([^\(\)]*\)/1/ ||
+			       $dstat =~ s/\{[^\{\}]*\}/1/ ||
+			       $dstat =~ s/.\[[^\[\]]*\]/1/)
 			{
 			}
 
@@ -5431,7 +5281,6 @@ sub process {
 			    $dstat !~ /^\.$Ident\s*=/ &&				# .foo =
 			    $dstat !~ /^(?:\#\s*$Ident|\#\s*$Constant)\s*$/ &&		# stringification #foo
 			    $dstat !~ /^do\s*$Constant\s*while\s*$Constant;?$/ &&	# do {...} while (...); // do {...} while (...)
-			    $dstat !~ /^while\s*$Constant\s*$Constant\s*$/ &&		# while (...) {...}
 			    $dstat !~ /^for\s*$Constant$/ &&				# for (...)
 			    $dstat !~ /^for\s*$Constant\s+(?:$Ident|-?$Constant)$/ &&	# for (...) bar()
 			    $dstat !~ /^do\s*{/ &&					# do {...
@@ -6054,7 +5903,8 @@ sub process {
 		my $barriers = qr{
 			mb|
 			rmb|
-			wmb
+			wmb|
+			read_barrier_depends
 		}x;
 		my $barrier_stems = qr{
 			mb__before_atomic|
@@ -6103,6 +5953,12 @@ sub process {
 			}
 		}
 
+# check for smp_read_barrier_depends and read_barrier_depends
+		if (!$file && $line =~ /\b(smp_|)read_barrier_depends\s*\(/) {
+			WARN("READ_BARRIER_DEPENDS",
+			     "$1read_barrier_depends should only be used in READ_ONCE or DEC Alpha code\n" . $herecurr);
+		}
+
 # check of hardware specific defines
 		if ($line =~ m@^.\s*\#\s*if.*\b(__i386__|__powerpc64__|__sun__|__s390x__)\b@ && $realfile !~ m@include/asm-@) {
 			CHK("ARCH_DEFINES",
@@ -6474,7 +6330,8 @@ sub process {
 			if (defined $cond) {
 				substr($s, 0, length($cond), '');
 			}
-			if ($s =~ /^\s*;/)
+			if ($s =~ /^\s*;/ &&
+			    $function_name ne 'uninitialized_var')
 			{
 				WARN("AVOID_EXTERNS",
 				     "externs should be avoided in .c files\n" .  $herecurr);
@@ -6493,13 +6350,17 @@ sub process {
 		}
 
 # check for function declarations that have arguments without identifier names
+# while avoiding uninitialized_var(x)
 		if (defined $stat &&
-		    $stat =~ /^.\s*(?:extern\s+)?$Type\s*(?:$Ident|\(\s*\*\s*$Ident\s*\))\s*\(\s*([^{]+)\s*\)\s*;/s &&
-		    $1 ne "void") {
-			my $args = trim($1);
+		    $stat =~ /^.\s*(?:extern\s+)?$Type\s*(?:($Ident)|\(\s*\*\s*$Ident\s*\))\s*\(\s*([^{]+)\s*\)\s*;/s &&
+		    (!defined($1) ||
+		     (defined($1) && $1 ne "uninitialized_var")) &&
+		     $2 ne "void") {
+			my $args = trim($2);
 			while ($args =~ m/\s*($Type\s*(?:$Ident|\(\s*\*\s*$Ident?\s*\)\s*$balanced_parens)?)/g) {
 				my $arg = trim($1);
-				if ($arg =~ /^$Type$/ && $arg !~ /enum\s+$Ident$/) {
+				if ($arg =~ /^$Type$/ &&
+					$arg !~ /enum\s+$Ident$/) {
 					WARN("FUNCTION_ARGUMENTS",
 					     "function definition argument '$arg' should also have an identifier name\n" . $herecurr);
 				}
@@ -6617,22 +6478,41 @@ sub process {
 			}
 		}
 
-# check for IS_ENABLED() without CONFIG_<FOO> ($rawline for comments too)
-		if ($rawline =~ /\bIS_ENABLED\s*\(\s*(\w+)\s*\)/ && $1 !~ /^${CONFIG_}/) {
-			WARN("IS_ENABLED_CONFIG",
-			     "IS_ENABLED($1) is normally used as IS_ENABLED(${CONFIG_}$1)\n" . $herecurr);
-		}
-
 # check for #if defined CONFIG_<FOO> || defined CONFIG_<FOO>_MODULE
-		if ($line =~ /^\+\s*#\s*if\s+defined(?:\s*\(?\s*|\s+)(${CONFIG_}[A-Z_]+)\s*\)?\s*\|\|\s*defined(?:\s*\(?\s*|\s+)\1_MODULE\s*\)?\s*$/) {
+		if ($line =~ /^\+\s*#\s*if\s+defined(?:\s*\(?\s*|\s+)(CONFIG_[A-Z_]+)\s*\)?\s*\|\|\s*defined(?:\s*\(?\s*|\s+)\1_MODULE\s*\)?\s*$/) {
 			my $config = $1;
 			if (WARN("PREFER_IS_ENABLED",
-				 "Prefer IS_ENABLED(<FOO>) to ${CONFIG_}<FOO> || ${CONFIG_}<FOO>_MODULE\n" . $herecurr) &&
+				 "Prefer IS_ENABLED(<FOO>) to CONFIG_<FOO> || CONFIG_<FOO>_MODULE\n" . $herecurr) &&
 			    $fix) {
 				$fixed[$fixlinenr] = "\+#if IS_ENABLED($config)";
 			}
 		}
 
+# check for case / default statements not preceded by break/fallthrough/switch
+		if ($line =~ /^.\s*(?:case\s+(?:$Ident|$Constant)\s*|default):/) {
+			my $has_break = 0;
+			my $has_statement = 0;
+			my $count = 0;
+			my $prevline = $linenr;
+			while ($prevline > 1 && ($file || $count < 3) && !$has_break) {
+				$prevline--;
+				my $rline = $rawlines[$prevline - 1];
+				my $fline = $lines[$prevline - 1];
+				last if ($fline =~ /^\@\@/);
+				next if ($fline =~ /^\-/);
+				next if ($fline =~ /^.(?:\s*(?:case\s+(?:$Ident|$Constant)[\s$;]*|default):[\s$;]*)*$/);
+				$has_break = 1 if ($rline =~ /fall[\s_-]*(through|thru)/i);
+				next if ($fline =~ /^.[\s$;]*$/);
+				$has_statement = 1;
+				$count++;
+				$has_break = 1 if ($fline =~ /\bswitch\b|\b(?:break\s*;[\s$;]*$|exit\s*\(\b|return\b|goto\b|continue\b)/);
+			}
+			if (!$has_break && $has_statement) {
+				WARN("MISSING_BREAK",
+				     "Possible switch case/default not preceded by break or fallthrough comment\n" . $herecurr);
+			}
+		}
+
 # check for /* fallthrough */ like comment, prefer fallthrough;
 		my @fallthroughs = (
 			'fallthrough',
@@ -6748,8 +6628,7 @@ sub process {
 
 # check for various structs that are normally const (ops, kgdb, device_tree)
 # and avoid what seem like struct definitions 'struct foo {'
-		if (defined($const_structs) &&
-		    $line !~ /\bconst\b/ &&
+		if ($line !~ /\bconst\b/ &&
 		    $line =~ /\bstruct\s+($const_structs)\b(?!\s*\{)/) {
 			WARN("CONST_STRUCT",
 			     "struct $1 should normally be const\n" . $herecurr);
@@ -6980,33 +6859,9 @@ sub process {
 		if ($signoff == 0) {
 			ERROR("MISSING_SIGN_OFF",
 			      "Missing Signed-off-by: line(s)\n");
-		} elsif ($authorsignoff != 1) {
-			# authorsignoff values:
-			# 0 -> missing sign off
-			# 1 -> sign off identical
-			# 2 -> names and addresses match, comments mismatch
-			# 3 -> addresses match, names different
-			# 4 -> names match, addresses different
-			# 5 -> names match, addresses excluding subaddress details (refer RFC 5233) match
-
-			my $sob_msg = "'From: $author' != 'Signed-off-by: $author_sob'";
-
-			if ($authorsignoff == 0) {
-				ERROR("NO_AUTHOR_SIGN_OFF",
-				      "Missing Signed-off-by: line by nominal patch author '$author'\n");
-			} elsif ($authorsignoff == 2) {
-				CHK("FROM_SIGN_OFF_MISMATCH",
-				    "From:/Signed-off-by: email comments mismatch: $sob_msg\n");
-			} elsif ($authorsignoff == 3) {
-				WARN("FROM_SIGN_OFF_MISMATCH",
-				     "From:/Signed-off-by: email name mismatch: $sob_msg\n");
-			} elsif ($authorsignoff == 4) {
-				WARN("FROM_SIGN_OFF_MISMATCH",
-				     "From:/Signed-off-by: email address mismatch: $sob_msg\n");
-			} elsif ($authorsignoff == 5) {
-				WARN("FROM_SIGN_OFF_MISMATCH",
-				     "From:/Signed-off-by: email subaddress mismatch: $sob_msg\n");
-			}
+		} elsif (!$authorsignoff) {
+			WARN("NO_AUTHOR_SIGN_OFF",
+			     "Missing Signed-off-by: line by nominal patch author '$author'\n");
 		}
 	}
 
-- 
2.27.0