Linux 2.6.39 compat, zlib_deflate_workspacesize()

The function zlib_deflate_workspacesize() now take 2 arguments.
This was done to avoid always having to allocate the maximum size
workspace (268K).  The caller can now specific the windowBits and
memLevel compression parameters to get a smaller workspace.

For our purposes we introduce a spl_zlib_deflate_workspacesize()
wrapper which accepts both arguments.  When the two argument
version of zlib_deflate_workspacesize() is available the arguments
are passed through.  When it's not we assume the worst case and
a maximally sized workspace is used.

include/linux/zlib_compat.h

@@ -0,0 +1,37 @@
+/*****************************************************************************\
+ *  Copyright (C) 2011 Lawrence Livermore National Security, LLC.
+ *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
+ *  Written by Brian Behlendorf <behlendorf1@llnl.gov>.
+ *  UCRL-CODE-235197
+ *
+ *  This file is part of the SPL, Solaris Porting Layer.
+ *  For details, see <http://github.com/behlendorf/spl/>.
+ *
+ *  The SPL is free software; you can redistribute it and/or modify it
+ *  under the terms of the GNU General Public License as published by the
+ *  Free Software Foundation; either version 2 of the License, or (at your
+ *  option) any later version.
+ *
+ *  The SPL is distributed in the hope that it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with the SPL.  If not, see <http://www.gnu.org/licenses/>.
+\*****************************************************************************/
+
+#ifndef _SPL_ZLIB_COMPAT_H
+#define _SPL_ZLIB_COMPAT_H
+
+#include <linux/zlib.h>
+
+#ifdef HAVE_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE
+#define spl_zlib_deflate_workspacesize(wb, ml) \
+	zlib_deflate_workspacesize(wb, ml)
+#else
+#define spl_zlib_deflate_workspacesize(wb, ml) \
+	zlib_deflate_workspacesize()
+#endif /* HAVE_2ARGS_ZLIB_DEFLATE_WORKSPACESIZE */
+
+#endif /* SPL_ZLIB_COMPAT_H */

include/sys/types.h

@@ -41,6 +41,7 @@
 #include <linux/sysctl_compat.h>
 #include <linux/proc_compat.h>
 #include <linux/math64_compat.h>
+#include <linux/zlib_compat.h>
 
 #ifndef HAVE_UINTPTR_T
 typedef unsigned long			uintptr_t;