linux-kernel - Re: RFC: script to convert vsprintf uses of %pf to %ps and %pF to %pS

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Date:   Mon, 26 Nov 2018 14:35:17 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:     Joe Perches <coupons@...ches.com>
Cc:     Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Linus Torvalds <torvalds@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: RFC: script to convert vsprintf uses of %pf to %ps and %pF to %pS

Hi,

Cc-ing Petr and Steven

On (11/25/18 01:13), Joe Perches wrote:
> commit 04b8eb7a4ccd ("symbol lookup: introduce dereference_symbol_descriptor()}"
> 
> deprecated vsprintf extension %pf and %pF.
> 
> There are approximately these total uses of the symbolic
> lookup vsprintf extensions %p[SsFf]:
> 
> $ git grep '".*[^%]%p[SsFf]' | \
>   grep -oh '%p[SsFf]' | sort | uniq -c | sort -rn
>     231 %pS
>      65 %ps
>      60 %pf
>      47 %pF

I didn't bother to remove "pf/pF" because I didn't want to count on:
  a) everyone running checkpatch.pl
  b) everyone testing all printk-s they added

I guess pf/pF still can sneak in.

But I don't have a really strong opinion on this. If general
consensus is that we shall remove deprecated specifiers, then
I'm fine.

> which is about a 3:1 ratio favoring %pS
> 
> so a script to convert all the %pf uses to %ps and %pF uses to %pS
> could be useful.
> 
> There are a few files that appear should not be converted.
> 
> $ git grep -w --name-only -i '%pf'| \
>   grep -vP '^(?:Documentation|tools|include/linux/freezer.h)'| \
>   xargs sed -i -e 's/%pf/%ps/g' -e 's/%pF/%pS/g'
> 
> If that script above is run, it leaves the following patch
> to be applied:

After running this script I still have a bunch of leftovers:

//
// these two are probably not really relevant, but still - %pF/%pf
//
tools/lib/traceevent/event-parse.c:             if (asprintf(&format, "%%pf: (NO FORMAT FOUND at %llx)\n", addr) < 0)
tools/lib/traceevent/event-parse.c:     if (asprintf(&format, "%s: %s", "%pf", printk->printk) < 0)

arch/um/kernel/sysrq.c: pr_info(" [<%08lx>] %s%pF\n", address, reliable ? "" : "? ",
arch/x86/xen/multicalls.c:                              printk(KERN_DEBUG "  call %2d/%d: op=%lu arg=[%lx] result=%ld\t%pF\n",
kernel/async.c:         pr_debug("calling  %lli_%pF @ %i\n",
kernel/async.c:         pr_debug("initcall %lli_%pF returned 0 after %lld usecs\n",

	-ss