[PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Josh Triplett]

checkpatch warns about spaces both before and after the ':' separating a
bitfield name from its width.  However, many drivers do put space before
the : to line up the widths, which makes the definition significantly
more readable; checkpatch should not warn about that.  Remove the
warning for space before the ':' of a bitfield.

Reported-by: Nandini Hanumanthagowda <nandu.hgowda@gmail.com>
Reported-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
---

Nandini and Greg observed this issue as part of checkpatch warnings on a
staging driver (octeon-usb), and both agreed that checkpatch should not
issue this warning; patching accordingly.

 scripts/checkpatch.pl | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index ed16a68..9e36345 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -2934,8 +2934,7 @@ sub process {
 
 				# No spaces for:
 				#   ->
-				#   :   when part of a bitfield
-				} elsif ($op eq '->' || $opv eq ':B') {
+				} elsif ($op eq '->') {
 					if ($ctx =~ /Wx.|.xW/) {
 						if (ERROR("SPACING",
 							  "spaces prohibited around that '$op' $at\n" . $hereptr)) {
@@ -2947,6 +2946,19 @@ sub process {
 						}
 					}
 
+				#   :   when part of a bitfield
+				} elsif ($opv eq ':B') {
+					if ($ctx =~ /.xW/) {
+						if (ERROR("SPACING",
+							  "spaces prohibited after that '$op' $at\n" . $hereptr)) {
+							$good = $fix_elements[$n] . rtrim($fix_elements[$n + 1]);
+							if (defined $fix_elements[$n + 2]) {
+								$fix_elements[$n + 2] =~ s/^\s+//;
+							}
+							$line_fixed = 1;
+						}
+					}
+
 				# , must have a space on the right.
 				} elsif ($op eq ',') {
 					if ($ctx !~ /.x[WEC]/ && $cc !~ /^}/) {
-- 
1.8.4.rc3

Re: [PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Joe Perches]

On Mon, 2013-10-14 at 10:32 -0700, Josh Triplett wrote:
> checkpatch warns about spaces both before and after the ':' separating a
> bitfield name from its width.  However, many drivers do put space before
> the : to line up the widths, which makes the definition significantly
> more readable; checkpatch should not warn about that.  Remove the
> warning for space before the ':' of a bitfield.

There are a _bunch_ of different styles used for
alignment of bitfields.

$ grep -rPh --include=*.[ch] \
  '(?:unsigned\s+|signed\s+|)(char|short|long|long\s+long|\w+_t|(?:__|)(?:u|s)(?:8|16|32|64))\s+\w+\s*:\s*\d+\s*(?:,|;)' *

spaces before colon
spaces after colon
aligned on bitfield size

I'd just as soon make it a --strict check.

Re: [PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Josh Triplett]

On Mon, Oct 14, 2013 at 10:51:48AM -0700, Joe Perches wrote:
> On Mon, 2013-10-14 at 10:32 -0700, Josh Triplett wrote:
> > checkpatch warns about spaces both before and after the ':' separating a
> > bitfield name from its width.  However, many drivers do put space before
> > the : to line up the widths, which makes the definition significantly
> > more readable; checkpatch should not warn about that.  Remove the
> > warning for space before the ':' of a bitfield.
> 
> There are a _bunch_ of different styles used for
> alignment of bitfields.
> 
> $ grep -rPh --include=*.[ch] \
>   '(?:unsigned\s+|signed\s+|)(char|short|long|long\s+long|\w+_t|(?:__|)(?:u|s)(?:8|16|32|64))\s+\w+\s*:\s*\d+\s*(?:,|;)' *
> 
> spaces before colon
> spaces after colon
> aligned on bitfield size
> 
> I'd just as soon make it a --strict check.

I'd be fine with removing the check entirely, or making it --strict;
however, even for --strict mode I'd suggest applying this patch, as I
don't think checkpatch should ever prohibit spaces before the ':'.

- Josh Triplett

Re: [PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Joe Perches]

On Mon, 2013-10-14 at 11:00 -0700, Josh Triplett wrote:
> On Mon, Oct 14, 2013 at 10:51:48AM -0700, Joe Perches wrote:
> > On Mon, 2013-10-14 at 10:32 -0700, Josh Triplett wrote:
> > > checkpatch warns about spaces both before and after the ':' separating a
> > > bitfield name from its width.  However, many drivers do put space before
> > > the : to line up the widths, which makes the definition significantly
> > > more readable; checkpatch should not warn about that.  Remove the
> > > warning for space before the ':' of a bitfield.
> > 
> > There are a _bunch_ of different styles used for
> > alignment of bitfields.
> > 
> > $ grep -rPh --include=*.[ch] \
> >   '(?:unsigned\s+|signed\s+|)(char|short|long|long\s+long|\w+_t|(?:__|)(?:u|s)(?:8|16|32|64))\s+\w+\s*:\s*\d+\s*(?:,|;)' *
> > 
> > spaces before colon
> > spaces after colon
> > aligned on bitfield size
> > 
> > I'd just as soon make it a --strict check.
> 
> I'd be fine with removing the check entirely, or making it --strict;
> however, even for --strict mode I'd suggest applying this patch, as I
> don't think checkpatch should ever prohibit spaces before the ':'.

Maybe something like that patch, but spaces probably
should be prohibited after the : in a bitfield either.

This style is pretty common

		u32 dma_address0                   :30;
		u32 dma_0No_update                 : 1;
		u32 dma_0start                     : 1;
		u32 dma_addr_size                  :24;
		u32 DMA_maxpackets                 : 8;

Re: [PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Josh Triplett]

On Mon, Oct 14, 2013 at 11:04:38AM -0700, Joe Perches wrote:
> On Mon, 2013-10-14 at 11:00 -0700, Josh Triplett wrote:
> > On Mon, Oct 14, 2013 at 10:51:48AM -0700, Joe Perches wrote:
> > > On Mon, 2013-10-14 at 10:32 -0700, Josh Triplett wrote:
> > > > checkpatch warns about spaces both before and after the ':' separating a
> > > > bitfield name from its width.  However, many drivers do put space before
> > > > the : to line up the widths, which makes the definition significantly
> > > > more readable; checkpatch should not warn about that.  Remove the
> > > > warning for space before the ':' of a bitfield.
> > > 
> > > There are a _bunch_ of different styles used for
> > > alignment of bitfields.
> > > 
> > > $ grep -rPh --include=*.[ch] \
> > >   '(?:unsigned\s+|signed\s+|)(char|short|long|long\s+long|\w+_t|(?:__|)(?:u|s)(?:8|16|32|64))\s+\w+\s*:\s*\d+\s*(?:,|;)' *
> > > 
> > > spaces before colon
> > > spaces after colon
> > > aligned on bitfield size
> > > 
> > > I'd just as soon make it a --strict check.
> > 
> > I'd be fine with removing the check entirely, or making it --strict;
> > however, even for --strict mode I'd suggest applying this patch, as I
> > don't think checkpatch should ever prohibit spaces before the ':'.
> 
> Maybe something like that patch, but spaces probably
> should be prohibited after the : in a bitfield either.
> 
> This style is pretty common
> 
> 		u32 dma_address0                   :30;
> 		u32 dma_0No_update                 : 1;
> 		u32 dma_0start                     : 1;
> 		u32 dma_addr_size                  :24;
> 		u32 DMA_maxpackets                 : 8;

I'm fine with just dropping the check entirely; want a patch for that
instead?  It's a much simpler patch.

- Josh Triplett

Re: [PATCH] checkpatch: Allow spaces before the ':' of a bitfield

[Joe Perches]

On Mon, 2013-10-14 at 13:20 -0700, Josh Triplett wrote:
> On Mon, Oct 14, 2013 at 11:04:38AM -0700, Joe Perches wrote:
> > On Mon, 2013-10-14 at 11:00 -0700, Josh Triplett wrote:
> > > On Mon, Oct 14, 2013 at 10:51:48AM -0700, Joe Perches wrote:
> > > > On Mon, 2013-10-14 at 10:32 -0700, Josh Triplett wrote:
> > > > > checkpatch warns about spaces both before and after the ':' separating a
> > > > > bitfield name from its width.  However, many drivers do put space before
> > > > > the : to line up the widths, which makes the definition significantly
> > > > > more readable; checkpatch should not warn about that.  Remove the
> > > > > warning for space before the ':' of a bitfield.
> > > > 
> > > > There are a _bunch_ of different styles used for
> > > > alignment of bitfields.
> > > > 
> > > > $ grep -rPh --include=*.[ch] \
> > > >   '(?:unsigned\s+|signed\s+|)(char|short|long|long\s+long|\w+_t|(?:__|)(?:u|s)(?:8|16|32|64))\s+\w+\s*:\s*\d+\s*(?:,|;)' *
> > > > 
> > > > spaces before colon
> > > > spaces after colon
> > > > aligned on bitfield size
> > > > 
> > > > I'd just as soon make it a --strict check.
> > > 
> > > I'd be fine with removing the check entirely, or making it --strict;
> > > however, even for --strict mode I'd suggest applying this patch, as I
> > > don't think checkpatch should ever prohibit spaces before the ':'.
> > 
> > Maybe something like that patch, but spaces probably
> > should be prohibited after the : in a bitfield either.
> > 
> > This style is pretty common
> > 
> > 		u32 dma_address0                   :30;
> > 		u32 dma_0No_update                 : 1;
> > 		u32 dma_0start                     : 1;
> > 		u32 dma_addr_size                  :24;
> > 		u32 DMA_maxpackets                 : 8;
> 
> I'm fine with just dropping the check entirely; want a patch for that
> instead?  It's a much simpler patch.

Maybe Andy has an opinion?  He's the one that
wrote almost all of these SPACING checks.