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From: Mateusz Guzik <mjg@FreeBSD.org>
Date: Tue, 24 Mar 2015 00:10:12 +0000 (UTC)
To: src-committers@freebsd.org, svn-src-all@freebsd.org,
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Subject: svn commit: r280407 - head/sys/kern
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Author: mjg
Date: Tue Mar 24 00:10:11 2015
New Revision: 280407
URL: https://svnweb.freebsd.org/changeset/base/280407

Log:
  filedesc: microoptimize fget_unlocked by getting rid of fd < 0 branch
  
  Casting fd to an unsigned type simplifies fd range coparison to mere checking
  if the result is bigger than the table.

Modified:
  head/sys/kern/kern_descrip.c

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Tue Mar 24 00:01:30 2015	(r280406)
+++ head/sys/kern/kern_descrip.c	Tue Mar 24 00:10:11 2015	(r280407)
@@ -2342,7 +2342,7 @@ fget_unlocked(struct filedesc *fdp, int 
 #endif
 
 	fdt = fdp->fd_files;
-	if (fd < 0 || fd >= fdt->fdt_nfiles)
+	if ((u_int)fd >= fdt->fdt_nfiles)
 		return (EBADF);
 	/*
 	 * Fetch the descriptor locklessly.  We avoid fdrop() races by