[PATCH 3/9] New commands `enable probe' and `disable probe'.

[Jose E. Marchesi]

Hi Sergio.
    
    > This patch adds the above-mentioned commands to the generic probe abstraction
    > implemented in probe.[ch].  The effects associated to enabling or disabling a
    > probe depend on the type of probe being handled, and is triggered by invoking
    > two back-end hooks in `probe_ops'.
    >
    > In case some particular probe type does not support the notion of enabling
    > and/or disabling, the corresponding fields on `probe_ops' can be initialized
    > to NULL.  This is the case of SystemTap probes.
    
    Thanks for the patch, Jose.  Comments below, as usual.

I agree/comply with all these comments :)