uprobes/core: Clean up, refactor and improve the code

Make the uprobes code readable to me:

 - improve the Kconfig text so that a mere mortal gets some idea
   what CONFIG_UPROBES=y is really about

 - do trivial renames to standardize around the uprobes_*() namespace

 - clean up and simplify various code flow details

 - separate basic blocks of functionality

 - line break artifact and white space related removal

 - use standard local varible definition blocks

 - use vertical spacing to make things more readable

 - remove unnecessary volatile

 - restructure comment blocks to make them more uniform and
   more readable in general

Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Anton Arapov <anton@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Link: http://lkml.kernel.org/n/tip-ewbwhb8o6navvllsauu7k07p@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
index 8208234..072df39 100644
--- a/arch/x86/include/asm/uprobes.h
+++ b/arch/x86/include/asm/uprobes.h
@@ -1,7 +1,7 @@
 #ifndef _ASM_UPROBES_H
 #define _ASM_UPROBES_H
 /*
- * Userspace Probes (UProbes) for x86
+ * User-space Probes (UProbes) for x86
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -24,19 +24,20 @@
  */
 
 typedef u8 uprobe_opcode_t;
-#define MAX_UINSN_BYTES 16
-#define UPROBES_XOL_SLOT_BYTES	128	/* to keep it cache aligned */
 
-#define UPROBES_BKPT_INSN 0xcc
-#define UPROBES_BKPT_INSN_SIZE 1
+#define MAX_UINSN_BYTES			  16
+#define UPROBES_XOL_SLOT_BYTES		 128	/* to keep it cache aligned */
+
+#define UPROBES_BKPT_INSN		0xcc
+#define UPROBES_BKPT_INSN_SIZE		   1
 
 struct uprobe_arch_info {
-	u16			fixups;
+	u16				fixups;
 #ifdef CONFIG_X86_64
-	unsigned long rip_rela_target_address;
+	unsigned long			rip_rela_target_address;
 #endif
 };
 
 struct uprobe;
-extern int analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
+extern int arch_uprobes_analyze_insn(struct mm_struct *mm, struct uprobe *uprobe);
 #endif	/* _ASM_UPROBES_H */