From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Alastair D'Silva" <alastair@d-silva.org>
Date: Mon, 15 Apr 2019 10:44:39 +0000
Subject: RE: [PATCH 3/4] lib/hexdump.c: Replace ascii bool in hex_dump_to_buffer with flags
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References: <20190410031720.11067-1-alastair@au1.ibm.com> <20190410031720.11067-4-alastair@au1.ibm.com> <20190412141211.lvnz6wb7mwkykmxf@pathway.suse.cz> <093301d4f187$da0756a0$8e1603e0$@d-silva.org> <20190415092424.qos7d54nbyr5hphu@pathway.suse.cz> <0da301d4f373$01d5bb80$05813280$@d-silva.org> <10c791893f034c26b4fee1a4659133e5@AcuMS.aculab.com>
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To: 'David Laight' <David.Laight@ACULAB.COM>, 'Petr Mladek' <pmladek@suse.com>
Cc: 'Alastair D'Silva' <alastair@au1.ibm.com>, 'Jani Nikula' <jani.nikula@linux.intel.com>, 'Joonas Lahtinen' <joonas.lahtinen@linux.intel.com>, 'Rodrigo Vivi' <rodrigo.vivi@intel.com>, 'David Airlie' <airlied@linux.ie>, 'Daniel Vetter' <daniel@ffwll.ch>, 'Karsten Keil' <isdn@linux-pingi.de>, 'Jassi Brar' <jassisinghbrar@gmail.com>, 'Tom Lendacky' <thomas.lendacky@amd.com>, "'David S. Miller'" <davem@davemloft.net>, 'Jose Abreu' <Jose.Abreu@synopsys.com>, 'Kalle Valo' <kvalo@codeaurora.org>, 'Stanislaw Gruszka' <sgruszka@redhat.com>, 'Benson Leung' <bleung@chromium.org>, 'Enric Balletbo i Serra' <enric.balletbo@collabora.com>, "'James E.J. Bottomley'" <jejb@linux.ibm.com>, "'Martin K. Petersen'" <martin.petersen@oracle.com>

> -----Original Message-----
> From: David Laight <David.Laight@ACULAB.COM>
> Sent: Monday, 15 April 2019 8:21 PM
> To: 'Alastair D'Silva' <alastair@d-silva.org>; 'Petr Mladek'
> <pmladek@suse.com>
> Cc: 'Alastair D'Silva' <alastair@au1.ibm.com>; 'Jani Nikula'
> <jani.nikula@linux.intel.com>; 'Joonas Lahtinen'
> <joonas.lahtinen@linux.intel.com>; 'Rodrigo Vivi' <rodrigo.vivi@intel.com>;
> 'David Airlie' <airlied@linux.ie>; 'Daniel Vetter' <daniel@ffwll.ch>; 'Karsten
> Keil' <isdn@linux-pingi.de>; 'Jassi Brar' <jassisinghbrar@gmail.com>; 'Tom
> Lendacky' <thomas.lendacky@amd.com>; 'David S. Miller'
> <davem@davemloft.net>; 'Jose Abreu' <Jose.Abreu@synopsys.com>; 'Kalle
> Valo' <kvalo@codeaurora.org>; 'Stanislaw Gruszka' <sgruszka@redhat.com>;
> 'Benson Leung' <bleung@chromium.org>; 'Enric Balletbo i Serra'
> <enric.balletbo@collabora.com>; 'James E.J. Bottomley'
> <jejb@linux.ibm.com>; 'Martin K. Petersen' <martin.petersen@oracle.com>;
> 'Greg Kroah-Hartman' <gregkh@linuxfoundation.org>; 'Alexander Viro'
> <viro@zeniv.linux.org.uk>; 'Sergey Senozhatsky'
> <sergey.senozhatsky@gmail.com>; 'Steven Rostedt'
> <rostedt@goodmis.org>; 'Andrew Morton' <akpm@linux-foundation.org>;
> intel-gfx@lists.freedesktop.org; dri-devel@lists.freedesktop.org; linux-
> kernel@vger.kernel.org; netdev@vger.kernel.org;
> ath10k@lists.infradead.org; linux-wireless@vger.kernel.org; linux-
> scsi@vger.kernel.org; linux-fbdev@vger.kernel.org;
> devel@driverdev.osuosl.org; linux-fsdevel@vger.kernel.org
> Subject: RE: [PATCH 3/4] lib/hexdump.c: Replace ascii bool in
> hex_dump_to_buffer with flags
> 
> From: Alastair D'Silva
> > Sent: 15 April 2019 11:07
> ...
> > In the above example the author only wants the hex output, while in
> > other situations, both hex & ASCII output is desirable. If you just
> > want ASCII output, the caller should just use a printk or one of it's
> wrappers.
> 
> Hexdump will 'sanitise' the ASCII.
> 

This is functionality that doesn't exist in the current hexdump implementation (you always get the hex version).

I think a better option would be to factor out the sanitisation and expose that as a separate function.

> Although I think you'd want a 'no hex' flag to suppress the hex.
> 
> Probably more useful flags are ones to suppress the address column.

This is already supported by the prefix_type parameter - are you proposing that we eliminate the parameter & combine it with flags?

> I've also used flags to enable (or disable) suppression of multiple lines of
> zeros of constant bytes.
> In that case you may want hexdump to return the flags for the next call when
> a large buffer is being dumped in fragments.
 
I'm afraid I don't quite follow here, hex_dump_to_buffer doesn't alter the flags, so the caller already knows it. 

-- 
Alastair D'Silva           mob: 0423 762 819
skype: alastair_dsilva     msn: alastair@d-silva.org
blog: http://alastair.d-silva.org    Twitter: @EvilDeece