On Thu, Mar 28, 2019 at 11:03:50AM +0200, Andy Shevchenko wrote:

On Wed, Mar 27, 2019 at 05:34:59PM -0700, Life is hard, and then you die wrote:

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On Wed, Mar 27, 2019 at 09:46:48AM +0200, Andy Shevchenko wrote:

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On Wed, Mar 27, 2019 at 3:49 AM Ronald Tschalär [off-list ref] wrote:

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This introduces print_hex_dump_to_cb() which contains all the hexdump
formatting minus the actual printk() call, allowing an arbitrary print
function to be supplied instead. And print_hex_dump() is re-implemented
using print_hex_dump_to_cb().

This allows other hex-dump logging functions to be provided which call
printk() differently or even log the hexdump somewhere entirely
different.

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In any case, don't do it like this. smaller non-recursive printf() is
better than one big receursive call.
When it looks like an optimization, it's actually a regression.

Not sure where you see recursion here - are you referring to the
callback approach?

%pV is a recursive printf().

Ah!

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Since dev_printk() ends up calling printk with a
dictionary as well as additional formatting, vs print_hex_dump()'s
stright use of printk, this seemed like the best way accommodate
various possible ways of logging the messages. But as per below I
guess this is moot.

I recommend to read this: https://lwn.net/Articles/780556/

Thanks, quite informative.


  Cheers,

  Ronald