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From: Robert Watson <rwatson@FreeBSD.org>
Date: Tue, 16 Dec 2008 17:03:22 +0000 (UTC)
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Subject: cvs commit: src/sys/net pfil.c
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rwatson     2008-12-16 17:03:22 UTC

  FreeBSD src repository

  Modified files:
    sys/net              pfil.c 
  Log:
  SVN rev 186187 on 2008-12-16 17:03:22Z by rwatson
  
  A few locking fixes and cleanups to pfil hook registration,
  unregistration, and execution:
  
  - Add some brackets for clarity and trim a bit of vertical whitespace.
  - Remove comments that may not contribute to clarity, such as "Lock"
    before acquiring a lock and "Get memory" before allocating memory.
  - During hook registration, don't drop pfil_list_lock between checking
    for a duplicate and registering the hook, as this leaves a race
    condition by failing to enforce the "no duplicate hooks" invariant.
  - Don't lock the hook during registration, since it's not yet in use.
  - Document assumption that hooks will be quiesced before being
    unregistered.
  - Don't write-lock hooks during removal because they are assumed
    quiesced.
  - Rename "done" label to "locked_error" to be clear that it's an error
    path on the way out of hook execution.
  
  MFC after:      pretty soon
  
  Revision  Changes    Path
  1.16      +10 -32    src/sys/net/pfil.c