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From: Poul-Henning Kamp <phk@FreeBSD.org>
Date: Thu, 19 Aug 2004 19:51:51 +0000 (UTC)
To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org,
	cvs-all@FreeBSD.org
X-FreeBSD-CVS-Branch: HEAD
Subject: cvs commit: src/sys/sys bio.h src/sys/kern subr_disk.c
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phk         2004-08-19 19:51:51 UTC

  FreeBSD src repository

  Modified files:
    sys/sys              bio.h 
    sys/kern             subr_disk.c 
  Log:
  Add bioq_takefirst().
  
  If the bioq is empty, NULL is returned.  Otherwise the front element
  is removed and returned.
  
  This can simplify locking in many drivers from:
  
          lock()
          bp = bioq_first(bq);
          if (bp == NULL) {
                  unlock()
                  return
          }
          bioq_remove(bp, bq)
          unlock
  to:
          lock()
          bp = bioq_takefirst(bq);
          unlock()
          if (bp == NULL)
                  return;
  
  Revision  Changes    Path
  1.81      +11 -6     src/sys/kern/subr_disk.c
  1.140     +2 -0      src/sys/sys/bio.h