linux-kernel - Re: [PATCH v7 08/13] lib/vsprintf: Remove support for %pF and %pf in favour of %pS and %ps

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Date:   Wed, 2 Oct 2019 15:06:40 +0300
From:   Sakari Ailus <sakari.ailus@...ux.intel.com>
To:     Petr Mladek <pmladek@...e.com>
Cc:     rafael@...nel.org, linux-kernel@...r.kernel.org,
        Rob Herring <robh@...nel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Joe Perches <joe@...ches.com>, devicetree@...r.kernel.org,
        linux-acpi@...r.kernel.org
Subject: Re: [PATCH v7 08/13] lib/vsprintf: Remove support for %pF and %pf in
 favour of %pS and %ps

Hi Petr,

Thank you for the review.

On Tue, Sep 24, 2019 at 12:38:29PM +0200, Petr Mladek wrote:
> On Wed 2019-09-18 16:34:14, Sakari Ailus wrote:
> > %pS and %ps are now the preferred conversion specifiers to print function
> > names. The functionality is equivalent; remove the old, deprecated %pF
> > and %pf support.
> > 
> > --- a/lib/vsprintf.c
> > +++ b/lib/vsprintf.c
> > @@ -909,7 +909,7 @@ char *symbol_string(char *buf, char *end, void *ptr,
> >  #ifdef CONFIG_KALLSYMS
> >  	if (*fmt == 'B')
> >  		sprint_backtrace(sym, value);
> > -	else if (*fmt != 'f' && *fmt != 's')
> > +	else if (*fmt != 's')
> >  		sprint_symbol(sym, value);
> >  	else
> >  		sprint_symbol_no_offset(sym, value);
> > @@ -2007,9 +2007,7 @@ static char *kobject_string(char *buf, char *end, void *ptr,
> >   *
> >   * - 'S' For symbolic direct pointers (or function descriptors) with offset
> >   * - 's' For symbolic direct pointers (or function descriptors) without offset
> > - * - 'F' Same as 'S'
> > - * - 'f' Same as 's'
> > - * - '[FfSs]R' as above with __builtin_extract_return_addr() translation
> > + * - '[Ss]R' as above with __builtin_extract_return_addr() translation
> >   * - 'B' For backtraced symbolic direct pointers with offset
> >   * - 'R' For decoded struct resource, e.g., [mem 0x0-0x1f 64bit pref]
> >   * - 'r' For raw struct resource, e.g., [mem 0x0-0x1f flags 0x201]
> > @@ -2112,8 +2110,6 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr,
> >  	      struct printf_spec spec)
> >  {
> >  	switch (*fmt) {
> > -	case 'F':
> > -	case 'f':
> >  	case 'S':
> >  	case 's':
> >  		ptr = dereference_symbol_descriptor(ptr);
> 
> IMHO, we should do the same also in vbin_printf().
> 
> The compatibility with traceevent tools was discussed in the thread
> https://lkml.kernel.org/r/20190910084707.18380-2-sakari.ailus@linux.intel.com
> 
> If I understand it correctly the tools should be able to handle stored
> 'f' and 'F' modifiers because they might be produced by
> older kernels. But new kernels should not longer produce them.

Agreed.

> 
> Otherwise the patch looks good to me. I am getting used to the fact
> that we will remove the obsolete specifiers completely.

I'll address this in v8 soon.

-- 
Regards,

Sakari Ailus
sakari.ailus@...ux.intel.com