linux-kernel - Re: [PATCH v1 1/1] dm integrity: Use %*ph for printing hexdump of a small buffer

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Message-ID: <ZIiGyPMMcIxZHH9u@smile.fi.intel.com>
Date:   Tue, 13 Jun 2023 18:10:00 +0300
From:   'Andy Shevchenko' <andriy.shevchenko@...ux.intel.com>
To:     David Laight <David.Laight@...lab.com>
Cc:     Mike Snitzer <snitzer@...nel.org>,
        Heinz Mauelshagen <heinzm@...hat.com>,
        "dm-devel@...hat.com" <dm-devel@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Alasdair Kergon <agk@...hat.com>
Subject: Re: [PATCH v1 1/1] dm integrity: Use %*ph for printing hexdump of a
 small buffer

On Tue, Jun 13, 2023 at 01:13:54PM +0000, David Laight wrote:
> From: Andy Shevchenko
> > Sent: 12 June 2023 22:48
> > 
> > The kernel already has a helper to print a hexdump of a small
> > buffer via pointer extension. Use that instead of open coded
> > variant.
> > 
> > In long term it helps to kill pr_cont() or at least narrow down
> > its use.
> > 
> > Note, the format is slightly changed, i.e. the colon is not printed
> > before the buffer dump and the trailing space is always printed.
> > These are not a problem since it's a debug message. Also the IV dump
> > is limited by 64 bytes which seems fine.
> ...
> > +#define DEBUG_bytes(bytes, len, msg, ...)	printk(KERN_DEBUG msg " %*ph\n", ##__VA_ARGS__, len,
> > bytes)
> 
> Using:
> 	printf(KERN_DEBUG msg "%s%*ph\n", ##__VA_ARGS__, len ? ": " : "", len, bytes)
> would add back the optional ':'.

Yes, I considered that and decided to avoid. This is debug and hence the format
may vary anyway. That said, up to maintainers.

-- 
With Best Regards,
Andy Shevchenko