cvs commit: src/sys/dev/sound/pcm sndstat.c

Don Lewis truckman at
Mon Sep 13 23:43:47 PDT 2004

truckman    2004-09-14 06:43:46 UTC

  FreeBSD src repository

  Modified files:        (Branch: RELENG_5)
    sys/dev/sound/pcm    sndstat.c 
  MFC sndstat.c 1.18
  >   Convert sndstat_lock from a mutex to an sx lock.  sndstat_read()
  >   holds sndstat_lock across a call to uiomove(), which is not legal
  >   to do with a  mutex because of the possibility that the data transfer
  >   could sleep because of a page fault.  It is not possible to just
  >   unlock the mutex for the uiomove() call without introducing another
  >   locking mechanism to prevent the body of sndstat_read() from being
  >   re-entered.  Converting sndstat_lock to an sx lock is the least
  >   complicated change.
  LOR:            030
  Approved by:    re (scottl)
  Revision  Changes    Path  +29 -26    src/sys/dev/sound/pcm/sndstat.c

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