Messages in this thread | | | Date | Mon, 31 Oct 2022 13:23:54 -0500 | Subject | Re: new checkpatch flexible array test ? (was Re: [PATCH v4 12/14] gunyah: rsc_mgr: Add RPC for console services) | From | "Gustavo A. R. Silva" <> |
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On 10/3/22 00:38, Joe Perches wrote: > On Mon, 2022-10-03 at 07:29 +0200, Greg Kroah-Hartman wrote: >> On Sun, Oct 02, 2022 at 06:46:30PM -0700, Joe Perches wrote: >>> 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: >>> --- > [] >>> diff --git 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*(?:$balanced_parens)?)\s*;\s*$/) {
This sounds great. We need the same for one-element arrays. :) Both zero-length and one-element arrays are deprecated.
> > This should actually be: > > $lines[$linenr] =~ /^[\+ ]\}(?:\s*__\w+\s*(?:$balanced_parens)?)*\s*;\s*$/) {
I agree. Thanks.
> > as it was missing a * for uses like > > int foo[0]; > } __packed __aligned(4); > > and uses without any attribute at all > >>> + 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 ($prevline =~ /^[\+ ]\s*$/ && >>> $line =~ /^\+\s*$/ && >> >> This is a question for Gustavo, who did all the work here. Gustavo, >> does the above checkpatch change look good to you?
Yep; the idea is great. :)
Another alternative to stop those fake flex-arrays from entering the codebase is to run Coccinelle scripts during linux-next builds, as suggested by Elena Reshetova at LSSEU a couple of months ago.
However, if these can be stopped with checkpatch it'd be really helpful, as well.
Thanks -- Gustavo
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