Re: [PATCH v5 0/4] make '%pD' print the full path of file

From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Jia He <justin.he@arm.com>
Cc: Petr Mladek <pmladek@suse.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Sergey Senozhatsky <senozhatsky@chromium.org>,
	Rasmus Villemoes <linux@rasmusvillemoes.dk>,
	Jonathan Corbet <corbet@lwn.net>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Peter Zijlstra (Intel)" <peterz@infradead.org>,
	Eric Biggers <ebiggers@google.com>,
	"Ahmed S. Darwish" <a.darwish@linutronix.de>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-fsdevel@vger.kernel.org,
	Matthew Wilcox <willy@infradead.org>,
	Christoph Hellwig <hch@infradead.org>,
	nd@arm.com
Subject: Re: [PATCH v5 0/4] make '%pD' print the full path of file
Date: Tue, 22 Jun 2021 17:43:23 +0300	[thread overview]
Message-ID: <YNH3C6P9i7xvapav@smile.fi.intel.com> (raw)
In-Reply-To: <20210622140634.2436-1-justin.he@arm.com>

On Tue, Jun 22, 2021 at 10:06:30PM +0800, Jia He wrote:
> Background
> ==========
> Linus suggested printing the full path of file instead of printing
> the components as '%pd'.
> 
> Typically, there is no need for printk specifiers to take any real locks
> (ie mount_lock or rename_lock). So I introduce a new helper d_path_fast
> which is similar to d_path except it doesn't take any seqlock/spinlock.
> 
> This series is based on Al Viro's d_path cleanup patches [1] which
> lifted the inner lockless loop into a new helper. 
> 
> Link: https://lkml.org/lkml/2021/5/18/1260 [1]
> 
> Test
> ====
> The cases I tested:
> 1. print '%pD' with full path of ext4 file
> 2. mount a ext4 filesystem upon a ext4 filesystem, and print the file
>    with '%pD'
> 3. all test_print selftests, including the new '%14pD' '%-14pD'

> 4. kasnprintf

I believe you are talking about kasprintf().

> Changelog
> =========
> v5:
> - remove the RFC tag

JFYI, when we drop RFC we usually start the series from v1.

> - refine the commit msg/comments(by Petr, Andy)
> - make using_scratch_space a new parameter of the test case 

Thanks for the update, I have found few minor things, please address them and
feel free to add
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> v4:
> - don't support spec.precision anymore for '%pD'
> - add Rasmus's patch into this series
>  
> v3:
> - implement new d_path_unsafe to use [buf, end] instead of stack space for
>   filling bytes (by Matthew)
> - add new test cases for '%pD'
> - drop patch "hmcdrv: remove the redundant directory path" before removing rfc.
> 
> v2: 
> - implement new d_path_fast based on Al Viro's patches
> - add check_pointer check (by Petr)
> - change the max full path size to 256 in stack space
> 
> v1: https://lkml.org/lkml/2021/5/8/122
> 
> 
> Jia He (3):
>   fs: introduce helper d_path_unsafe()
>   lib/vsprintf.c: make '%pD' print the full path of file
>   lib/test_printf.c: add test cases for '%pD'
> 
> Rasmus Villemoes (1):
>   lib/test_printf.c: split write-beyond-buffer check in two
> 
>  Documentation/core-api/printk-formats.rst |   5 +-
>  fs/d_path.c                               | 104 +++++++++++++++++++++-
>  include/linux/dcache.h                    |   1 +
>  lib/test_printf.c                         |  54 ++++++++---
>  lib/vsprintf.c                            |  40 ++++++++-
>  5 files changed, 184 insertions(+), 20 deletions(-)
> 
> -- 
> 2.17.1
> 

-- 
With Best Regards,
Andy Shevchenko