kern/143622: [pfil] [patch] unlock pfil lock while calling firewall hooks

Max Laier max at love2party.net
Mon Feb 8 02:10:04 UTC 2010


The following reply was made to PR kern/143622; it has been noted by GNATS.

From: Max Laier <max at love2party.net>
To: bug-followup at freebsd.org,
 gleb.kurtsou at gmail.com
Cc:  
Subject: Re: kern/143622: [pfil] [patch] unlock pfil lock while calling firewall hooks
Date: Mon, 8 Feb 2010 02:55:41 +0100

 Please no.  The rmlock is extremely lightweight (PCPU) in contrast to taking 
 and dropping the reference (atomic ops).  In addition, the read lock does not 
 mandate any locking model on the firewall and allows recursion, as well.
 
 Furthermore, there are many more locks that might be held from up/down the 
 stack - pfil consumer must not sleep (regardless of the pfil lock) and should 
 avoid recursion as much as possible.  Changing the pfil lock will not change 
 that ... nor does does changing any other locks in the stack ... it's just the 
 way it is with a layered design.
 
 Regards,
   Max


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