new checkpatch flexible array test ? (was Re: [PATCH v4 12/14] gunyah: rsc_mgr: Add RPC for console services)

Joe Perches
2022-10-03T01:46:47Z

On Fri, 2022-09-30 at 14:22 +0200, Greg Kroah-Hartman wrote:
> On Wed, Sep 28, 2022 at 12:56:31PM -0700, Elliot Berman wrote:
> > Gunyah resource manager defines a simple API for virtual machine log
> > sharing with the console service.
[]
> > diff --git a/include/linux/gunyah_rsc_mgr.h b/include/linux/gunyah_rsc_mgr.h
[]
> > +struct gh_rm_notif_vm_console_chars {
> > + u16 vmid;
> > + u16 num_bytes;
> > + u8 bytes[0];
>
> Please do not use [0] for new structures, otherwise we will just have to
> fix them up again as we are trying to get rid of all of these from the
> kernel. Just use "bytes[];" instead.

Maybe a checkpatch addition like:
---
scripts/checkpatch.pl | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 2737e4ced5745..187ed84c1f80a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -3948,6 +3948,17 @@ sub process {
}
}

+# check for zero length array declarations in likely structs
+ if ($line =~ /^\+\t($Declare\s*$Ident)\s*\[\s*0\s*\]\s*;\s*$/ &&
+ defined $lines[$linenr] &&
+ $lines[$linenr] =~ /^[\+ ]\}\s*(?:__\w+\s*(?:$balanced_parens)?)\s*;\s*$/) {
+ if (WARN("FLEXIBLE_ARRAY_ZERO",
+ "Prefer flexible length array declarations with [] over [0]\n" . $herecurr) &&
+ $fix) {
+ $fixed[$fixlinenr] =~ s/\[\s*0\s*\]/[]/;
+ }
+ }
+
# check for multiple consecutive blank lines
if ($prevline =~ /^[\+ ]\s*$/ &&
$line =~ /^\+\s*$/ &&