Re: [PATCH] Prefix each line of multiline printk(KERN_<level>"foo\nbar") with KERN_<level>

From: Maciej W. Rozycki
Date: Wed Aug 29 2007 - 07:23:16 EST


On Sun, 26 Aug 2007, Geert Uytterhoeven wrote:

> What I mean is that probably there used to be a printk() call starting with
> `\n'. Then someone added a `KERN_ERR' in front of it.

I gather '\n' at the beginning is to assure the following line is output
on a separate line rather than as a continuation of another one which may
have been output without a trailing '\n'. A situation where printk() is
called with a string containing no trailing '\n' may be discouraged, but
there are some more or less justified exceptions. For example the SCSI
disk spin-up code is one.

Therefore it may be reasonable for more critical messages -- perhaps not
ones at KERN_ERR, but certainly KERN_CRIT and higher ones -- that may
potentially happen asynchronously to start with '\n'. In this case a call
would look like this:

printk("\n" KERN_CRIT "The actual message.\n");

Of course based on "console_loglevel" and "default_message_level" the
leading '\n' may still get swallowed from what gets printed to the console
terminal, but in reality I do not think that poses a problem, as these
both can be set by a system administrator according to the local policy.

Maciej
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