[PATCH 2.6.11.2][1/2] printk with anti-cluttering-feature

From: Bodo Eggert (7eggert_at_gmx.de)
Date: 03/20/05

  • Next message: hui: "Re: Real-Time Preemption and RCU" 
    Date:	Sun, 20 Mar 2005 22:35:33 +0100 (CET)
To: Bodo Eggert <7eggert@gmx.de>

    Introduce printk_nospam, which will prevent duplicate and excessive
    printing.

    Signed-Off-By: Bodo Eggert <7eggert@gmx.de>

    diff -purNXdontdiff linux-2.6.11/include/linux/kernel.h linux-2.6.11.new/include/linux/kernel.h
    --- linux-2.6.11/include/linux/kernel.h 2005-03-03 15:42:13.000000000 +0100
    +++ linux-2.6.11.new/include/linux/kernel.h 2005-03-20 21:15:23.000000000 +0100
    @@ -104,6 +104,12 @@ extern int session_of_pgrp(int pgrp);
     asmlinkage int vprintk(const char *fmt, va_list args);
     asmlinkage int printk(const char * fmt, ...)
             __attribute__ ((format (printf, 1, 2)));
    +asmlinkage int printk_nospam(unsigned int magic, const char * fmt, ...)
    + __attribute__ ((format (printf, 2, 3)));
    +/* Don't print the previously printed message had the same magic or the rate
    + limit would be exceeded.
    + Hint: Use a unique random value for the magic, e.g. the first value from
    + cksum on the file you're editing */
     
     unsigned long int_sqrt(unsigned long);
     
    diff -purNXdontdiff linux-2.6.11/kernel/printk.c linux-2.6.11.new/kernel/printk.c
    --- linux-2.6.11/kernel/printk.c 2005-03-18 21:54:35.000000000 +0100
    +++ linux-2.6.11.new/kernel/printk.c 2005-03-20 21:15:14.000000000 +0100
    @@ -115,6 +115,8 @@ static int preferred_console = -1;
     /* Flag: console code may call schedule() */
     static int console_may_schedule;
     
    +static int antispam_magic;
    +
     /*
      * Setup a list of consoles. Called from init/main.c
      */
    @@ -517,6 +519,26 @@ asmlinkage int printk(const char *fmt, .
             va_list args;
             int r;
     
    + antispam_magic = 0;
    +
    + va_start(args, fmt);
    + r = vprintk(fmt, args);
    + va_end(args);
    +
    + return r;
    +}
    +
    +asmlinkage int printk_nospam(unsigned int magic, const char *fmt, ...)
    +{
    + va_list args;
    + int r;
    +
    + if (magic == antispam_magic)
    + return 0;
    + if (!printk_ratelimit())
    + return 0;
    + antispam_magic = magic;
    +
             va_start(args, fmt);
             r = vprintk(fmt, args);
             va_end(args);
    @@ -591,6 +613,7 @@ out:
             return printed_len;
     }
     EXPORT_SYMBOL(printk);
    +EXPORT_SYMBOL(printk_nospam);
     EXPORT_SYMBOL(vprintk);
     
     /**
    -
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