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Gmane
From: <danielfsantos <at> att.net>
Subject: [PATCH 0/5] Preliminary: Add error names & descrptions to printks
Newsgroups: gmane.linux.kbuild.devel
Date: Tuesday 17th September 2013 23:08:32 UTC (over 3 years ago)
This is a preliminary patch set as the root Makefile changes are not yet
correct.

Summary

Typically, we don't care about error messages or names in the kernel
because
userspace will manage that.  But sometimes we need to output an error
number
to printks and that creates a situation where a user, system admistrator or
developer must find an error number reference to figure out what went wrong
with a particular driver or whatever.  This patch adds two alternatives at
increasing memory costs:

1. print the number in addition to the name for 2k extra or
2. print the number, name and description for 6k extra.

This is fairly low cost for the person who wants to make life just a little
bit easier. The format of each is respectively the same as the following:

  printk("%d (%s)", err, err_name);
  printk("%d (%s: %s)", err, err_name, err_desc);

Theory

Error messages aren't printed often, so this data and code is designed to
be
compact at the expense of speed.  Rather than using an array of strings
that
would require both the text and a pointer to that text, we just cram a
range
of error names or descriptions into a single string with null character
delimiters.  When we want to retrieve a string, we just iterate through
that
string and count nulls.  This is slow, but it keeps it compact. (If this
becomes a bottleneck then something else is seriously wrong! :)
 
CD: 2ms