diff mbox series

[RFC] MAINTAINERS tag for cleanup robot

Message ID 20201121165058.1644182-1-trix@redhat.com
State New
Headers show
Series [RFC] MAINTAINERS tag for cleanup robot | expand

Commit Message

Tom Rix Nov. 21, 2020, 4:50 p.m. UTC
A difficult part of automating commits is composing the subsystem
preamble in the commit log.  For the ongoing effort of a fixer producing
one or two fixes a release the use of 'treewide:' does not seem appropriate.

It would be better if the normal prefix was used.  Unfortunately normal is
not consistent across the tree.

So I am looking for comments for adding a new tag to the MAINTAINERS file

	D: Commit subsystem prefix

ex/ for FPGA DFL DRIVERS

	D: fpga: dfl:

Continuing with cleaning up clang's -Wextra-semi-stmt

A significant number of warnings are caused by function like macros with
a trailing semicolon.  For example.

#define FOO(a) a++; <-- extra, unneeded semicolon
void bar() {
	int v = 0;
	FOO(a);
} 

Clang will warn at the FOO(a); expansion location. Instead of removing
the semicolon there,  the fixer removes semicolon from the macro
definition.  After the fixer, the code will be:

#define FOO(a) a++
void bar() {
	int v = 0;
	FOO(a);
} 

The fixer review is
https://reviews.llvm.org/D91789

A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
The false positives are caused by macros passed to other macros and by
some macro expansions that did not have an extra semicolon.

This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
warnings in linux-next.

An update to [RFC] clang tooling cleanup
This change adds the clang-tidy-fix as a top level target and
uses it to do the cleaning.  The next iteration will do a loop of
cleaners.  This will mean breaking clang-tidy-fix out into its own
processing function 'run_fixers'.

Makefile: Add toplevel target clang-tidy-fix to makefile

Calls clang-tidy with -fix option for a set of checkers that
programatically fixes the kernel source in place, treewide.

Signed-off-by: Tom Rix <trix@redhat.com>
---
 Makefile                               |  7 ++++---
 scripts/clang-tools/run-clang-tools.py | 20 +++++++++++++++++---
 2 files changed, 21 insertions(+), 6 deletions(-)

Comments

Joe Perches Nov. 21, 2020, 5:10 p.m. UTC | #1
On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
> A difficult part of automating commits is composing the subsystem
> preamble in the commit log.  For the ongoing effort of a fixer producing
> one or two fixes a release the use of 'treewide:' does not seem appropriate.
> 
> It would be better if the normal prefix was used.  Unfortunately normal is
> not consistent across the tree.
> 
> So I am looking for comments for adding a new tag to the MAINTAINERS file
> 
> 	D: Commit subsystem prefix
> 
> ex/ for FPGA DFL DRIVERS
> 
> 	D: fpga: dfl:

I'm all for it.  Good luck with the effort.  It's not completely trivial.

From a decade ago:

https://lore.kernel.org/lkml/1289919077.28741.50.camel@Joe-Laptop/

(and that thread started with extra semicolon patches too)

> Continuing with cleaning up clang's -Wextra-semi-stmt

> diff --git a/Makefile b/Makefile
[]
> @@ -1567,20 +1567,21 @@ help:
>  	 echo  ''
>  	@echo  'Static analysers:'
>  	@echo  '  checkstack      - Generate a list of stack hogs'
>  	@echo  '  versioncheck    - Sanity check on version.h usage'
>  	@echo  '  includecheck    - Check for duplicate included header files'
>  	@echo  '  export_report   - List the usages of all exported symbols'
>  	@echo  '  headerdep       - Detect inclusion cycles in headers'
>  	@echo  '  coccicheck      - Check with Coccinelle'
>  	@echo  '  clang-analyzer  - Check with clang static analyzer'
>  	@echo  '  clang-tidy      - Check with clang-tidy'
> +	@echo  '  clang-tidy-fix  - Check and fix with clang-tidy'

A pity the ordering of the code below isn't the same as the above.

> -PHONY += clang-tidy clang-analyzer
> +PHONY += clang-tidy-fix clang-tidy clang-analyzer
[]
> -clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
> +clang-tidy-fix clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
>  	$(call cmd,clang_tools)
>  else
> -clang-tidy clang-analyzer:
> +clang-tidy-fix clang-tidy clang-analyzer:

[]

> diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
[]
> @@ -22,43 +22,57 @@ def parse_arguments():
[]
>      parser.add_argument("type",
> -                        choices=["clang-tidy", "clang-analyzer"],
> +                        choices=["clang-tidy-fix", "clang-tidy", "clang-analyzer"],

etc...
James Bottomley Nov. 21, 2020, 5:18 p.m. UTC | #2
On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
> A difficult part of automating commits is composing the subsystem
> preamble in the commit log.  For the ongoing effort of a fixer
> producing
> one or two fixes a release the use of 'treewide:' does not seem
> appropriate.
> 
> It would be better if the normal prefix was used.  Unfortunately
> normal is
> not consistent across the tree.
> 
> 
> 	D: Commit subsystem prefix
> 
> ex/ for FPGA DFL DRIVERS
> 
> 	D: fpga: dfl:
> 

I've got to bet this is going to cause more issues than it solves. 
SCSI uses scsi: <driver>: for drivers but not every driver has a
MAINTAINERS entry.  We use either scsi: or scsi: core: for mid layer
things, but we're not consistent.  Block uses blk-<something>: for all
of it's stuff but almost no <somtehing>s have a MAINTAINERS entry.  So
the next thing you're going to cause is an explosion of suggested
MAINTAINERs entries.

Has anyone actually complained about treewide:?

James
Joe Perches Nov. 21, 2020, 6:02 p.m. UTC | #3
On Sat, 2020-11-21 at 09:18 -0800, James Bottomley wrote:
> On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
> > A difficult part of automating commits is composing the subsystem
> > preamble in the commit log.  For the ongoing effort of a fixer
> > producing one or two fixes a release the use of 'treewide:' does
> > not seem appropriate.
> > 
> > It would be better if the normal prefix was used.  Unfortunately
> > normal is not consistent across the tree.
> > 
> > 	D: Commit subsystem prefix
> > 
> > ex/ for FPGA DFL DRIVERS
> > 
> > 	D: fpga: dfl:
> 
> I've got to bet this is going to cause more issues than it solves. 
> SCSI uses scsi: <driver>: for drivers but not every driver has a
> MAINTAINERS entry.  We use either scsi: or scsi: core: for mid layer
> things, but we're not consistent.  Block uses blk-<something>: for all
> of it's stuff but almost no <somtehing>s have a MAINTAINERS entry.  So
> the next thing you're going to cause is an explosion of suggested
> MAINTAINERs entries.

As well as some changes require simultaneous changes across
multiple subsystems.

> Has anyone actually complained about treewide:?

It depends on what you mean by treewide:

If a treewide: patch is applied by some "higher level" maintainer,
then generally, no.

If the treewide patch is also cc'd to many individual maintainers,
then yes, many many times.

Mostly because patches cause what is in their view churn or that
changes are not specific to their subsystem grounds.

The treewide patch is sometimes dropped, sometimes broken up and
generally not completely applied.

What would be useful in many cases like this is for a pre and post
application of the treewide patch to be compiled and the object
code verified for lack of any logic change.

Unfortunately, gcc does not guarantee deterministic compilation so
this isn't feasible with at least gcc.  Does clang guarantee this?

I'm not sure it's possible:
https://blog.llvm.org/2019/11/deterministic-builds-with-clang-and-lld.html
Matthew Wilcox Nov. 22, 2020, 3:23 a.m. UTC | #4
On Sat, Nov 21, 2020 at 08:50:58AM -0800, trix@redhat.com wrote:
> The fixer review is
> https://reviews.llvm.org/D91789
> 
> A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
> The false positives are caused by macros passed to other macros and by
> some macro expansions that did not have an extra semicolon.
> 
> This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
> warnings in linux-next.

Are any of them not false-positives?  It's all very well to enable
stricter warnings, but if they don't fix any bugs, they're just churn.
Tom Rix Nov. 22, 2020, 2:46 p.m. UTC | #5
On 11/21/20 7:23 PM, Matthew Wilcox wrote:
> On Sat, Nov 21, 2020 at 08:50:58AM -0800, trix@redhat.com wrote:
>> The fixer review is
>> https://reviews.llvm.org/D91789
>>
>> A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
>> The false positives are caused by macros passed to other macros and by
>> some macro expansions that did not have an extra semicolon.
>>
>> This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
>> warnings in linux-next.
> Are any of them not false-positives?  It's all very well to enable
> stricter warnings, but if they don't fix any bugs, they're just churn.
>
While enabling additional warnings may be a side effect of this effort

the primary goal is to set up a cleaning robot. After that a refactoring robot.

Tom
Matthew Wilcox Nov. 22, 2020, 2:56 p.m. UTC | #6
On Sun, Nov 22, 2020 at 06:46:46AM -0800, Tom Rix wrote:
> 
> On 11/21/20 7:23 PM, Matthew Wilcox wrote:
> > On Sat, Nov 21, 2020 at 08:50:58AM -0800, trix@redhat.com wrote:
> >> The fixer review is
> >> https://reviews.llvm.org/D91789
> >>
> >> A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
> >> The false positives are caused by macros passed to other macros and by
> >> some macro expansions that did not have an extra semicolon.
> >>
> >> This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
> >> warnings in linux-next.
> > Are any of them not false-positives?  It's all very well to enable
> > stricter warnings, but if they don't fix any bugs, they're just churn.
> >
> While enabling additional warnings may be a side effect of this effort
> 
> the primary goal is to set up a cleaning robot. After that a refactoring robot.

Why do we need such a thing?  Again, it sounds like more churn.
It's really annoying when I'm working on something important that gets
derailed by pointless churn.  Churn also makes it harder to backport
patches to earlier kernels.
Tom Rix Nov. 22, 2020, 4:10 p.m. UTC | #7
On 11/22/20 6:56 AM, Matthew Wilcox wrote:
> On Sun, Nov 22, 2020 at 06:46:46AM -0800, Tom Rix wrote:
>> On 11/21/20 7:23 PM, Matthew Wilcox wrote:
>>> On Sat, Nov 21, 2020 at 08:50:58AM -0800, trix@redhat.com wrote:
>>>> The fixer review is
>>>> https://reviews.llvm.org/D91789
>>>>
>>>> A run over allyesconfig for x86_64 finds 62 issues, 5 are false positives.
>>>> The false positives are caused by macros passed to other macros and by
>>>> some macro expansions that did not have an extra semicolon.
>>>>
>>>> This cleans up about 1,000 of the current 10,000 -Wextra-semi-stmt
>>>> warnings in linux-next.
>>> Are any of them not false-positives?  It's all very well to enable
>>> stricter warnings, but if they don't fix any bugs, they're just churn.
>>>
>> While enabling additional warnings may be a side effect of this effort
>>
>> the primary goal is to set up a cleaning robot. After that a refactoring robot.
> Why do we need such a thing?  Again, it sounds like more churn.
> It's really annoying when I'm working on something important that gets
> derailed by pointless churn.  Churn also makes it harder to backport
> patches to earlier kernels.
>
A refactoring example on moving to treewide, consistent use of a new api may help.

Consider

2efc459d06f1630001e3984854848a5647086232

sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output

A new api for printing in the sysfs.  How do we use it treewide ?

Done manually, it would be a heroic effort requiring high level maintainers pushing and likely only get partially done.

If a refactoring programatic fixit is done and validated on a one subsystem, it can run on all the subsystems.

The effort is a couple of weeks to write and validate the fixer, hours to run over the tree.

It won't be perfect but will be better than doing it manually.

Tom
Tom Rix Nov. 22, 2020, 4:33 p.m. UTC | #8
On 11/21/20 9:10 AM, Joe Perches wrote:
> On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
>> A difficult part of automating commits is composing the subsystem
>> preamble in the commit log.  For the ongoing effort of a fixer producing
>> one or two fixes a release the use of 'treewide:' does not seem appropriate.
>>
>> It would be better if the normal prefix was used.  Unfortunately normal is
>> not consistent across the tree.
>>
>> So I am looking for comments for adding a new tag to the MAINTAINERS file
>>
>> 	D: Commit subsystem prefix
>>
>> ex/ for FPGA DFL DRIVERS
>>
>> 	D: fpga: dfl:
> I'm all for it.  Good luck with the effort.  It's not completely trivial.
>
> From a decade ago:
>
> https://lore.kernel.org/lkml/1289919077.28741.50.camel@Joe-Laptop/
>
> (and that thread started with extra semicolon patches too)

Reading the history, how about this.

get_mataintainer.pl outputs a single prefix, if multiple files have the same prefix it works, if they don't its an error.

Another script 'commit_one_file.sh' does the call to get_mainainter.pl to get the prefix and be called by run-clang-tools.py to get the fixer specific message.

Defer minimizing the commits by combining similar subsystems till later.

In a steady state case, this should be uncommon.


>
>> Continuing with cleaning up clang's -Wextra-semi-stmt
>> diff --git a/Makefile b/Makefile
> []
>> @@ -1567,20 +1567,21 @@ help:
>>  	 echo  ''
>>  	@echo  'Static analysers:'
>>  	@echo  '  checkstack      - Generate a list of stack hogs'
>>  	@echo  '  versioncheck    - Sanity check on version.h usage'
>>  	@echo  '  includecheck    - Check for duplicate included header files'
>>  	@echo  '  export_report   - List the usages of all exported symbols'
>>  	@echo  '  headerdep       - Detect inclusion cycles in headers'
>>  	@echo  '  coccicheck      - Check with Coccinelle'
>>  	@echo  '  clang-analyzer  - Check with clang static analyzer'
>>  	@echo  '  clang-tidy      - Check with clang-tidy'
>> +	@echo  '  clang-tidy-fix  - Check and fix with clang-tidy'
> A pity the ordering of the code below isn't the same as the above.

Taken care thanks!

Tom
James Bottomley Nov. 22, 2020, 4:49 p.m. UTC | #9
On Sun, 2020-11-22 at 08:10 -0800, Tom Rix wrote:
> On 11/22/20 6:56 AM, Matthew Wilcox wrote:
> > On Sun, Nov 22, 2020 at 06:46:46AM -0800, Tom Rix wrote:
> > > On 11/21/20 7:23 PM, Matthew Wilcox wrote:
> > > > On Sat, Nov 21, 2020 at 08:50:58AM -0800, trix@redhat.com
> > > > wrote:
> > > > > The fixer review is
> > > > > https://reviews.llvm.org/D91789
> > > > > 
> > > > > A run over allyesconfig for x86_64 finds 62 issues, 5 are
> > > > > false positives. The false positives are caused by macros
> > > > > passed to other macros and by some macro expansions that did
> > > > > not have an extra semicolon.
> > > > > 
> > > > > This cleans up about 1,000 of the current 10,000 -Wextra-
> > > > > semi-stmt warnings in linux-next.
> > > > Are any of them not false-positives?  It's all very well to
> > > > enable stricter warnings, but if they don't fix any bugs,
> > > > they're just churn.
> > > > 
> > > While enabling additional warnings may be a side effect of this
> > > effort
> > > 
> > > the primary goal is to set up a cleaning robot. After that a
> > > refactoring robot.
> > Why do we need such a thing?  Again, it sounds like more churn.
> > It's really annoying when I'm working on something important that
> > gets derailed by pointless churn.  Churn also makes it harder to
> > backport patches to earlier kernels.
> > 
> A refactoring example on moving to treewide, consistent use of a new
> api may help.
> 
> Consider
> 
> 2efc459d06f1630001e3984854848a5647086232
> 
> sysfs: Add sysfs_emit and sysfs_emit_at to format sysfs output
> 
> A new api for printing in the sysfs.  How do we use it treewide ?
> 
> Done manually, it would be a heroic effort requiring high level
> maintainers pushing and likely only get partially done.
> 
> If a refactoring programatic fixit is done and validated on a one
> subsystem, it can run on all the subsystems.
> 
> The effort is a couple of weeks to write and validate the fixer,
> hours to run over the tree.
> 
> It won't be perfect but will be better than doing it manually.

Here's a thought: perhaps we don't.  sysfs_emit isn't a "new api" its a
minor rewrap of existing best practice.  The damage caused by the churn
of forcing its use everywhere would far outweigh any actual benefit
because pretty much every bug in this area has already been caught and
killed by existing tools.  We can enforce sysfs_emit going forwards
using tools like checkpatch but there's no benefit and a lot of harm to
be done by trying to churn the entire tree retrofitting it (both in
terms of review time wasted as well as patch series derailed).

James
Joe Perches Nov. 22, 2020, 6:22 p.m. UTC | #10
On Sun, 2020-11-22 at 08:33 -0800, Tom Rix wrote:
> On 11/21/20 9:10 AM, Joe Perches wrote:
> > On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
> > > A difficult part of automating commits is composing the subsystem
> > > preamble in the commit log.  For the ongoing effort of a fixer producing
> > > one or two fixes a release the use of 'treewide:' does not seem appropriate.
> > > 
> > > It would be better if the normal prefix was used.  Unfortunately normal is
> > > not consistent across the tree.
> > > 
> > > So I am looking for comments for adding a new tag to the MAINTAINERS file
> > > 
> > > 	D: Commit subsystem prefix
> > > 
> > > ex/ for FPGA DFL DRIVERS
> > > 
> > > 	D: fpga: dfl:
> > I'm all for it.  Good luck with the effort.  It's not completely trivial.
> > 
> > From a decade ago:
> > 
> > https://lore.kernel.org/lkml/1289919077.28741.50.camel@Joe-Laptop/
> > 
> > (and that thread started with extra semicolon patches too)
> 
> Reading the history, how about this.
> 
> get_maintainer.pl outputs a single prefix, if multiple files have the
> same prefix it works, if they don't its an error.
> 
> Another script 'commit_one_file.sh' does the call to get_mainainter.pl
> to get the prefix and be called by run-clang-tools.py to get the fixer
> specific message.

It's not whether the script used is get_maintainer or any other script,
the question is really if the MAINTAINERS file is the appropriate place
to store per-subsystem patch specific prefixes.

It is.

Then the question should be how are the forms described and what is the
inheritance priority.  My preference would be to have a default of
inherit the parent base and add basename(subsystem dirname).

Commit history seems to have standardized on using colons as the separator
between the commit prefix and the subject.

A good mechanism to explore how various subsystems have uses prefixes in
the past might be something like:

$ git log --no-merges --pretty='%s' -<commit_count> <subsystem_path> | \
  perl -n -e 'print substr($_, 0, rindex($_, ":") + 1) . "\n";' | \
  sort | uniq -c | sort -rn

Using 10000 for commit_count and drivers/scsi for subsystem_path, the
top 40 entries are below:

About 1% don't have a colon, and there is no real consistency even
within individual drivers below scsi.  For instance, qla2xxx:

     1	    814 scsi: qla2xxx:
     2	    691 scsi: lpfc:
     3	    389 scsi: hisi_sas:
     4	    354 scsi: ufs:
     5	    339 scsi:
     6	    291 qla2xxx:
     7	    256 scsi: megaraid_sas:
     8	    249 scsi: mpt3sas:
     9	    200 hpsa:
    10	    190 scsi: aacraid:
    11	    174 lpfc:
    12	    153 scsi: qedf:
    13	    144 scsi: smartpqi:
    14	    139 scsi: cxlflash:
    15	    122 scsi: core:
    16	    110 [SCSI] qla2xxx:
    17	    108 ncr5380:
    18	     98 scsi: hpsa:
    19	     97 
    20	     89 treewide:
    21	     88 mpt3sas:
    22	     86 scsi: libfc:
    23	     85 scsi: qedi:
    24	     84 scsi: be2iscsi:
    25	     81 [SCSI] qla4xxx:
    26	     81 hisi_sas:
    27	     81 block:
    28	     75 megaraid_sas:
    29	     71 scsi: sd:
    30	     69 [SCSI] hpsa:
    31	     68 cxlflash:
    32	     65 scsi: libsas:
    33	     65 scsi: fnic:
    34	     61 scsi: scsi_debug:
    35	     60 scsi: arcmsr:
    36	     57 be2iscsi:
    37	     53 atp870u:
    38	     51 scsi: bfa:
    39	     50 scsi: storvsc:
    40	     48 sd:
Joe Perches Nov. 22, 2020, 6:23 p.m. UTC | #11
On Sun, 2020-11-22 at 08:49 -0800, James Bottomley wrote:
> We can enforce sysfs_emit going forwards
> using tools like checkpatch

It's not really possible for checkpatch to find or warn about
sysfs uses of sprintf. checkpatch is really just a trivial
line-by-line parser and it has no concept of code intent.

It just can't warn on every use of the sprintf family.
There are just too many perfectly valid uses.

> but there's no benefit and a lot of harm to
> be done by trying to churn the entire tree

Single uses of sprintf for sysfs is not really any problem.

But likely there are still several possible overrun sprintf/snprintf
paths in sysfs.  Some of them are very obscure and unlikely to be
found by a robot as the logic for sysfs buf uses can be fairly twisty.

But provably correct conversions IMO _should_ be done and IMO churn
considerations should generally have less importance.
Finn Thain Nov. 22, 2020, 10:33 p.m. UTC | #12
On Sun, 22 Nov 2020, Joe Perches wrote:

> On Sun, 2020-11-22 at 08:49 -0800, James Bottomley wrote:
> > We can enforce sysfs_emit going forwards
> > using tools like checkpatch
> 
> It's not really possible for checkpatch to find or warn about
> sysfs uses of sprintf. checkpatch is really just a trivial
> line-by-line parser and it has no concept of code intent.
> 

Checkpatch does suffer from the limitations of regular expressions. But 
that doesn't stop people from using it. Besides, Coccinelle can do 
analyses that can't be done with regular expressions, so it's moot.

> It just can't warn on every use of the sprintf family.
> There are just too many perfectly valid uses.
> 
> > but there's no benefit and a lot of harm to
> > be done by trying to churn the entire tree
> 
> Single uses of sprintf for sysfs is not really any problem.
> 
> But likely there are still several possible overrun sprintf/snprintf
> paths in sysfs.  Some of them are very obscure and unlikely to be
> found by a robot as the logic for sysfs buf uses can be fairly twisty.
> 

Logic errors of this kind are susceptible to fuzzing, formal methods, 
symbolic execution etc. No doubt there are other techniques that I don't 
know about.

> But provably correct conversions IMO _should_ be done and IMO churn 
> considerations should generally have less importance.
> 

Provably equivalent conversions are provably churn. So apparently you're 
advocating changes that are not provably equivalent.

These are patches for code not that's not been shown to be buggy. Code 
which, after patching, can be shown to be free of a specific kind of 
theoretical bug. Hardly "provably correct".

The problem is, the class of theoretical bugs that can be avoided in this 
way is probably limitless, as is the review cost and the risk of 
accidental regressions. And the payoff is entirely theoretical.

Moreover, the patch review workload for skilled humans is being generated 
by the automation, which is completely backwards: the machine is supposed 
to be helping.
Joe Perches Nov. 23, 2020, 12:53 a.m. UTC | #13
On Mon, 2020-11-23 at 09:33 +1100, Finn Thain wrote:
> On Sun, 22 Nov 2020, Joe Perches wrote:

> > But provably correct conversions IMO _should_ be done and IMO churn 
> > considerations should generally have less importance.
[]
> Moreover, the patch review workload for skilled humans is being generated 
> by the automation, which is completely backwards: the machine is supposed 
> to be helping.

Which is why the provably correct matters.

coccinelle transforms can be, but are not necessarily, provably correct.

The _show transforms done via the sysfs_emit_dev.cocci script are correct
as in commit aa838896d87a ("drivers core: Use sysfs_emit and sysfs_emit_at
for show(device *...) functions")

Worthwhile?  A different question, but I think yes as it reduces the
overall question space of the existing other sprintf overrun possibilities.
Jani Nikula Nov. 23, 2020, 3:52 p.m. UTC | #14
On Sat, 21 Nov 2020, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
>> A difficult part of automating commits is composing the subsystem
>> preamble in the commit log.  For the ongoing effort of a fixer
>> producing
>> one or two fixes a release the use of 'treewide:' does not seem
>> appropriate.
>> 
>> It would be better if the normal prefix was used.  Unfortunately
>> normal is
>> not consistent across the tree.
>> 
>> 
>> 	D: Commit subsystem prefix
>> 
>> ex/ for FPGA DFL DRIVERS
>> 
>> 	D: fpga: dfl:
>> 
>
> I've got to bet this is going to cause more issues than it solves.

Agreed.

> SCSI uses scsi: <driver>: for drivers but not every driver has a
> MAINTAINERS entry.  We use either scsi: or scsi: core: for mid layer
> things, but we're not consistent.  Block uses blk-<something>: for all
> of it's stuff but almost no <somtehing>s have a MAINTAINERS entry.  So
> the next thing you're going to cause is an explosion of suggested
> MAINTAINERs entries.

On the one hand, adoption of new MAINTAINERS entries has been really
slow. Look at B, C, or P, for instance. On the other hand, if this were
to get adopted, you'll potentially get conflicting prefixes for patches
touching multiple files. Then what?

I'm guessing a script looking at git log could come up with better
suggestions for prefixes via popularity contest than manually maintained
MAINTAINERS entries. It might not always get it right, but then human
outsiders aren't going to always get it right either.

Now you'll only need Someone(tm) to write the script. ;)

Something quick like this:

git log --since={1year} --pretty=format:%s -- <FILES> |\
	grep -v "^\(Merge\|Revert\)" |\
        sed 's/:[^:]*$//' |\
        sort | uniq -c | sort -rn | head -5

already gives me results that really aren't worse than some of the
prefixes invented by drive-by contributors.

> Has anyone actually complained about treewide:?

As Joe said, I'd feel silly applying patches to drivers with that
prefix. If it gets applied by someone else higher up, literally
treewide, then no complaints.

BR,
Jani.
Lukas Bulwahn Nov. 23, 2020, 4:17 p.m. UTC | #15
On Mon, Nov 23, 2020 at 4:52 PM Jani Nikula <jani.nikula@linux.intel.com> wrote:
>
> On Sat, 21 Nov 2020, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> > On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
> >> A difficult part of automating commits is composing the subsystem
> >> preamble in the commit log.  For the ongoing effort of a fixer
> >> producing
> >> one or two fixes a release the use of 'treewide:' does not seem
> >> appropriate.
> >>
> >> It would be better if the normal prefix was used.  Unfortunately
> >> normal is
> >> not consistent across the tree.
> >>
> >>
> >>      D: Commit subsystem prefix
> >>
> >> ex/ for FPGA DFL DRIVERS
> >>
> >>      D: fpga: dfl:
> >>
> >
> > I've got to bet this is going to cause more issues than it solves.
>
> Agreed.
>

Tom, this a problem only kernel janitors encounter; all other
developers really do not have that issue. The time spent on creating
the patch is much larger than the amount saved if the commit log
header line prefix would be derived automatically. I believe Julia
Lawall, Arnd Bergmann and Nathan Chancellor as long-term
high-frequency janitors do have already scripted approaches to that
issue. Maybe they simply need to share these scripts with you and you
consolidate them and share with everyone?

Also, making clean-up patches cumbersome has a positive side as well;
maintainers are not swamped with fully automated patch submissions.
There have been some bad experiences with some submitters on that in
the past...

> > SCSI uses scsi: <driver>: for drivers but not every driver has a
> > MAINTAINERS entry.  We use either scsi: or scsi: core: for mid layer
> > things, but we're not consistent.  Block uses blk-<something>: for all
> > of it's stuff but almost no <somtehing>s have a MAINTAINERS entry.  So
> > the next thing you're going to cause is an explosion of suggested
> > MAINTAINERs entries.
>
> On the one hand, adoption of new MAINTAINERS entries has been really
> slow. Look at B, C, or P, for instance. On the other hand, if this were
> to get adopted, you'll potentially get conflicting prefixes for patches
> touching multiple files. Then what?
>
> I'm guessing a script looking at git log could come up with better
> suggestions for prefixes via popularity contest than manually maintained
> MAINTAINERS entries. It might not always get it right, but then human
> outsiders aren't going to always get it right either.
>
> Now you'll only need Someone(tm) to write the script. ;)
>
> Something quick like this:
>
> git log --since={1year} --pretty=format:%s -- <FILES> |\
>         grep -v "^\(Merge\|Revert\)" |\
>         sed 's/:[^:]*$//' |\
>         sort | uniq -c | sort -rn | head -5
>
> already gives me results that really aren't worse than some of the
> prefixes invented by drive-by contributors.
>

I agree I do not see the need to introduce something in MAINTAINERS;
from my observations maintaining MAINTAINERS, there is sufficient work
on adoption and maintenance of the existing entries already without
such an yet another additional entry. Some entries are outdated or
wrong and the janitor task of cleaning those up is already enough work
for involved janitors and enough churn for involved maintainers. So a
machine-learned approach as above is probably good enough, but if you
think you need more complex rules try to learn them from the data at
hand... certainly a nice task to do with machine learning on commit
message prefixes.

Lukas
Tom Rix Nov. 23, 2020, 5:06 p.m. UTC | #16
On 11/22/20 10:22 AM, Joe Perches wrote:
> On Sun, 2020-11-22 at 08:33 -0800, Tom Rix wrote:
>> On 11/21/20 9:10 AM, Joe Perches wrote:
>>> On Sat, 2020-11-21 at 08:50 -0800, trix@redhat.com wrote:
>>>> A difficult part of automating commits is composing the subsystem
>>>> preamble in the commit log.  For the ongoing effort of a fixer producing
>>>> one or two fixes a release the use of 'treewide:' does not seem appropriate.
>>>>
>>>> It would be better if the normal prefix was used.  Unfortunately normal is
>>>> not consistent across the tree.
>>>>
>>>> So I am looking for comments for adding a new tag to the MAINTAINERS file
>>>>
>>>> 	D: Commit subsystem prefix
>>>>
>>>> ex/ for FPGA DFL DRIVERS
>>>>
>>>> 	D: fpga: dfl:
>>> I'm all for it.  Good luck with the effort.  It's not completely trivial.
>>>
>>> From a decade ago:
>>>
>>> https://lore.kernel.org/lkml/1289919077.28741.50.camel@Joe-Laptop/
>>>
>>> (and that thread started with extra semicolon patches too)
>> Reading the history, how about this.
>>
>> get_maintainer.pl outputs a single prefix, if multiple files have the
>> same prefix it works, if they don't its an error.
>>
>> Another script 'commit_one_file.sh' does the call to get_mainainter.pl
>> to get the prefix and be called by run-clang-tools.py to get the fixer
>> specific message.
> It's not whether the script used is get_maintainer or any other script,
> the question is really if the MAINTAINERS file is the appropriate place
> to store per-subsystem patch specific prefixes.
>
> It is.
>
> Then the question should be how are the forms described and what is the
> inheritance priority.  My preference would be to have a default of
> inherit the parent base and add basename(subsystem dirname).
>
> Commit history seems to have standardized on using colons as the separator
> between the commit prefix and the subject.
>
> A good mechanism to explore how various subsystems have uses prefixes in
> the past might be something like:
>
> $ git log --no-merges --pretty='%s' -<commit_count> <subsystem_path> | \
>   perl -n -e 'print substr($_, 0, rindex($_, ":") + 1) . "\n";' | \
>   sort | uniq -c | sort -rn

Thanks, I have shamelessly stolen this line and limited the commits to the maintainer.

I will post something once the generation of the prefixes is done.

Tom
diff mbox series

Patch

diff --git a/Makefile b/Makefile
index 47a8add4dd28..57756dbb767b 100644
--- a/Makefile
+++ b/Makefile
@@ -1567,20 +1567,21 @@  help:
 	 echo  ''
 	@echo  'Static analysers:'
 	@echo  '  checkstack      - Generate a list of stack hogs'
 	@echo  '  versioncheck    - Sanity check on version.h usage'
 	@echo  '  includecheck    - Check for duplicate included header files'
 	@echo  '  export_report   - List the usages of all exported symbols'
 	@echo  '  headerdep       - Detect inclusion cycles in headers'
 	@echo  '  coccicheck      - Check with Coccinelle'
 	@echo  '  clang-analyzer  - Check with clang static analyzer'
 	@echo  '  clang-tidy      - Check with clang-tidy'
+	@echo  '  clang-tidy-fix  - Check and fix with clang-tidy'
 	@echo  ''
 	@echo  'Tools:'
 	@echo  '  nsdeps          - Generate missing symbol namespace dependencies'
 	@echo  ''
 	@echo  'Kernel selftest:'
 	@echo  '  kselftest         - Build and run kernel selftest'
 	@echo  '                      Build, install, and boot kernel before'
 	@echo  '                      running kselftest on it'
 	@echo  '                      Run as root for full coverage'
 	@echo  '  kselftest-all     - Build kernel selftest'
@@ -1842,30 +1843,30 @@  nsdeps: modules
 quiet_cmd_gen_compile_commands = GEN     $@
       cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
 
 $(extmod-prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
 	$(if $(KBUILD_EXTMOD),,$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)) \
 	$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
 	$(call if_changed,gen_compile_commands)
 
 targets += $(extmod-prefix)compile_commands.json
 
-PHONY += clang-tidy clang-analyzer
+PHONY += clang-tidy-fix clang-tidy clang-analyzer
 
 ifdef CONFIG_CC_IS_CLANG
 quiet_cmd_clang_tools = CHECK   $<
       cmd_clang_tools = $(PYTHON3) $(srctree)/scripts/clang-tools/run-clang-tools.py $@ $<
 
-clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
+clang-tidy-fix clang-tidy clang-analyzer: $(extmod-prefix)compile_commands.json
 	$(call cmd,clang_tools)
 else
-clang-tidy clang-analyzer:
+clang-tidy-fix clang-tidy clang-analyzer:
 	@echo "$@ requires CC=clang" >&2
 	@false
 endif
 
 # Scripts to check various things for consistency
 # ---------------------------------------------------------------------------
 
 PHONY += includecheck versioncheck coccicheck export_report
 
 includecheck:
diff --git a/scripts/clang-tools/run-clang-tools.py b/scripts/clang-tools/run-clang-tools.py
index fa7655c7cec0..c177ca822c56 100755
--- a/scripts/clang-tools/run-clang-tools.py
+++ b/scripts/clang-tools/run-clang-tools.py
@@ -22,43 +22,57 @@  def parse_arguments():
     Returns:
         args: Dict of parsed args
         Has keys: [path, type]
     """
     usage = """Run clang-tidy or the clang static-analyzer on a
         compilation database."""
     parser = argparse.ArgumentParser(description=usage)
 
     type_help = "Type of analysis to be performed"
     parser.add_argument("type",
-                        choices=["clang-tidy", "clang-analyzer"],
+                        choices=["clang-tidy-fix", "clang-tidy", "clang-analyzer"],
                         help=type_help)
     path_help = "Path to the compilation database to parse"
     parser.add_argument("path", type=str, help=path_help)
 
     return parser.parse_args()
 
 
 def init(l, a):
     global lock
     global args
     lock = l
     args = a
 
 
 def run_analysis(entry):
     # Disable all checks, then re-enable the ones we want
     checks = "-checks=-*,"
-    if args.type == "clang-tidy":
+    fix = ""
+    header_filter = ""
+    if args.type == "clang-tidy-fix":
+        checks += "linuxkernel-macro-trailing-semi"
+        #
+        # Fix this
+        # #define M(a) a++; <-- clang-tidy fixes the problem here
+        # int f() {
+        #   int v = 0;
+        #   M(v);  <-- clang reports problem here
+        #   return v;
+        # }
+        fix += "-fix"
+        header_filter += "-header-filter=.*"
+    elif args.type == "clang-tidy":
         checks += "linuxkernel-*"
     else:
         checks += "clang-analyzer-*"
-    p = subprocess.run(["clang-tidy", "-p", args.path, checks, entry["file"]],
+    p = subprocess.run(["clang-tidy", "-p", args.path, checks, header_filter, fix, entry["file"]],
                        stdout=subprocess.PIPE,
                        stderr=subprocess.STDOUT,
                        cwd=entry["directory"])
     with lock:
         sys.stderr.buffer.write(p.stdout)
 
 
 def main():
     args = parse_arguments()