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From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Thu, 6 Nov 2014 07:44:10 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r274166 - head/sys/kern
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Author: mjg
Date: Thu Nov  6 07:44:10 2014
New Revision: 274166
URL: https://svnweb.freebsd.org/changeset/base/274166

Log:
  filedesc: avoid taking fdesc_mtx when not necessary in fddrop
  
  No functional changes.

Modified:
  head/sys/kern/kern_descrip.c

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Thu Nov  6 07:37:31 2014	(r274165)
+++ head/sys/kern/kern_descrip.c	Thu Nov  6 07:44:10 2014	(r274166)
@@ -1859,11 +1859,13 @@ fddrop(struct filedesc *fdp)
 {
 	int i;
 
-	mtx_lock(&fdesc_mtx);
-	i = --fdp->fd_holdcnt;
-	mtx_unlock(&fdesc_mtx);
-	if (i > 0)
-		return;
+	if (fdp->fd_holdcnt > 1) {
+		mtx_lock(&fdesc_mtx);
+		i = --fdp->fd_holdcnt;
+		mtx_unlock(&fdesc_mtx);
+		if (i > 0)
+			return;
+	}
 
 	FILEDESC_LOCK_DESTROY(fdp);
 	uma_zfree(filedesc0_zone, fdp);