Linux 2.6.32 compat, proc_handler() API change

As of linux-2.6.32 the 'struct file *filp' argument was dropped from
the proc_handle() prototype.  It was apparently unused _almost_
everywhere in the kernel and this was simply cleanup.

I've added a new SPL_AC_5ARGS_PROC_HANDLER autoconf check for this and
the proper compat macros to correctly define the prototypes and some
helper functions.  It's not pretty but API compat changes rarely are.

include/linux/sysctl_compat.h

@@ -0,0 +1,72 @@
+#ifndef _SPL_SYSCTL_COMPAT_H
+#define _SPL_SYSCTL_COMPAT_H
+
+#include <linux/sysctl.h>
+
+/* proc_handler() / proc_do* API changes
+ * 2.6.x  - 2.6.31: 6 args, prototype includes 'struct file *'
+ * 2.6.32 - 2.6.y:  5 args, removed unused 'struct file *' from prototype
+ *
+ * Generic SPL_PROC_HANDLER() macro should be used for correct prototypes.
+ * It will define the following function arguments which can and should be
+ * used with the spl_proc_* helper macros.
+ *
+ *   struct ctl_table *table,
+ *   int write,
+ *   struct file *filp [2.6.31 and earlier kernels],
+ *   void __user *buffer,
+ *   size_t *lenp,
+ *   loff_t *ppos,
+ */
+#ifdef HAVE_5ARGS_PROC_HANDLER
+
+#define SPL_PROC_HANDLER(proc_handler)                                       \
+static int                                                                   \
+proc_handler(struct ctl_table *table, int write,                             \
+             void __user *buffer, size_t *lenp, loff_t *ppos)              
+                                                                           
+#define spl_proc_dostring(table, write, filp, buffer, lenp, ppos)            \
+	proc_dostring(table, write, buffer, lenp, ppos)                    
+#define spl_proc_dointvec(table, write, filp, buffer, lenp, ppos)            \
+	proc_dointvec(table, write, buffer, lenp, ppos)                    
+#define spl_proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos)     \
+	proc_dointvec_minmax(table, write, buffer, lenp, ppos)                    
+#define spl_proc_dointvec_jiffies(table, write, filp, buffer, lenp, ppos)    \
+	proc_dointvec_jiffies(table, write, buffer, lenp, ppos)                    
+#define spl_proc_dointvec_userhz_jiffies(table,write,filp,buffer,lenp,ppos)  \
+	proc_dointvec_userhz_jiffies(table, write, buffer, lenp, ppos)                    
+#define spl_proc_dointvec_ms_jiffies(table,write,filp,buffer,lenp,ppos)      \
+	proc_dointvec_ms_jiffies(table, write, buffer, lenp, ppos)                    
+#define spl_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos)        \
+	proc_doulongvec_minmax(table, write, buffer, lenp, ppos)
+#define spl_proc_doulongvec_ms_jiffies_minmax(table,write,filp,buffer,lenp,ppos)  \
+	proc_doulongvec_ms_jiffies_minmax(table, write, buffer, lenp, ppos)
+                                                                           
+#else /* HAVE_5ARGS_PROC_HANDLER */                                         
+                                                                           
+#define SPL_PROC_HANDLER(proc_handler)                                       \
+static int                                                                   \
+proc_handler(struct ctl_table *table, int write, struct file *filp,          \
+             void __user *buffer, size_t *lenp, loff_t *ppos)              
+                                                                           
+#define spl_proc_dostring(table, write, filp, buffer, lenp, ppos)            \
+	proc_dostring(table, write, filp, buffer, lenp, ppos)              
+#define spl_proc_dointvec(table, write, filp, buffer, lenp, ppos)            \
+	proc_dointvec(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos)     \
+	proc_dointvec_minmax(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_dointvec_jiffies(table, write, filp, buffer, lenp, ppos)    \
+	proc_dointvec_jiffies(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_dointvec_userhz_jiffies(table,write,filp,buffer,lenp,ppos)  \
+	proc_dointvec_userhz_jiffies(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_dointvec_ms_jiffies(table, write, filp, buffer, lenp, ppos) \
+	proc_dointvec_ms_jiffies(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos)        \
+	proc_doulongvec_minmax(table, write, filp, buffer, lenp, ppos)
+#define spl_proc_doulongvec_ms_jiffies_minmax(table,write,filp,buffer,lenp,ppos)  \
+	proc_doulongvec_ms_jiffies_minmax(table,write,filp,buffer,lenp,ppos)
+
+
+#endif /* HAVE_5ARGS_PROC_HANDLER */
+
+#endif /* _SPL_SYSCTL_COMPAT_H */

include/sys/types.h

@@ -19,6 +19,7 @@ extern "C" {
 #include <linux/kallsyms_compat.h>
 #include <linux/mutex_compat.h>
 #include <linux/module_compat.h>
+#include <linux/sysctl_compat.h>
 
 #ifndef HAVE_UINTPTR_T
 typedef unsigned long			uintptr_t;