x86, mm: fault.c, simplify kmmio_fault()

Impact: cleanup

Remove an #ifdef from kmmio_fault() - we can do this by
providing default implementations for is_kmmio_active()
and kmmio_handler(). The compiler optimizes it all away
in the !CONFIG_MMIOTRACE case.

Also, while at it, clean up mmiotrace.h a bit:

 - standard header guards
 - standard vertical spaces for structure definitions

No code changed (both with mmiotrace on and off in the config):

   text	   data	    bss	    dec	    hex	filename
   2947	     12	     12	   2971	    b9b	fault.o.before
   2947	     12	     12	   2971	    b9b	fault.o.after

Cc: Pekka Paalanen <pq@iki.fi>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/fault.c

@@ -55,13 +55,14 @@ enum x86_pf_error_code {
 	PF_INSTR	=		1 << 4,
 };
 
+/*
+ * (returns 0 if mmiotrace is disabled)
+ */
 static inline int kmmio_fault(struct pt_regs *regs, unsigned long addr)
 {
-#ifdef CONFIG_MMIOTRACE
 	if (unlikely(is_kmmio_active()))
 		if (kmmio_handler(regs, addr) == 1)
 			return -1;
-#endif
 	return 0;
 }
 

include/linux/mmiotrace.h

@@ -1,5 +1,5 @@
-#ifndef MMIOTRACE_H
-#define MMIOTRACE_H
+#ifndef _LINUX_MMIOTRACE_H
+#define _LINUX_MMIOTRACE_H
 
 #include <linux/types.h>
 #include <linux/list.h>
@@ -13,28 +13,34 @@ typedef void (*kmmio_post_handler_t)(struct kmmio_probe *,
 				unsigned long condition, struct pt_regs *);
 
 struct kmmio_probe {
-	struct list_head list; /* kmmio internal list */
-	unsigned long addr; /* start location of the probe point */
-	unsigned long len; /* length of the probe region */
-	kmmio_pre_handler_t pre_handler; /* Called before addr is executed. */
-	kmmio_post_handler_t post_handler; /* Called after addr is executed */
-	void *private;
+	/* kmmio internal list: */
+	struct list_head	list;
+	/* start location of the probe point: */
+	unsigned long		addr;
+	/* length of the probe region: */
+	unsigned long		len;
+	/* Called before addr is executed: */
+	kmmio_pre_handler_t	pre_handler;
+	/* Called after addr is executed: */
+	kmmio_post_handler_t	post_handler;
+	void			*private;
 };
 
+extern unsigned int kmmio_count;
+
+extern int register_kmmio_probe(struct kmmio_probe *p);
+extern void unregister_kmmio_probe(struct kmmio_probe *p);
+
+#ifdef CONFIG_MMIOTRACE
 /* kmmio is active by some kmmio_probes? */
 static inline int is_kmmio_active(void)
 {
-	extern unsigned int kmmio_count;
 	return kmmio_count;
 }
 
-extern int register_kmmio_probe(struct kmmio_probe *p);
-extern void unregister_kmmio_probe(struct kmmio_probe *p);
-
 /* Called from page fault handler. */
 extern int kmmio_handler(struct pt_regs *regs, unsigned long addr);
 
-#ifdef CONFIG_MMIOTRACE
 /* Called from ioremap.c */
 extern void mmiotrace_ioremap(resource_size_t offset, unsigned long size,
 							void __iomem *addr);
@@ -43,7 +49,17 @@ extern void mmiotrace_iounmap(volatile void __iomem *addr);
 /* For anyone to insert markers. Remember trailing newline. */
 extern int mmiotrace_printk(const char *fmt, ...)
 				__attribute__ ((format (printf, 1, 2)));
-#else
+#else /* !CONFIG_MMIOTRACE: */
+static inline int is_kmmio_active(void)
+{
+	return 0;
+}
+
+static inline int kmmio_handler(struct pt_regs *regs, unsigned long addr)
+{
+	return 0;
+}
+
 static inline void mmiotrace_ioremap(resource_size_t offset,
 					unsigned long size, void __iomem *addr)
 {
@@ -63,28 +79,28 @@ static inline int mmiotrace_printk(const char *fmt, ...)
 #endif /* CONFIG_MMIOTRACE */
 
 enum mm_io_opcode {
-	MMIO_READ = 0x1,     /* struct mmiotrace_rw */
-	MMIO_WRITE = 0x2,    /* struct mmiotrace_rw */
-	MMIO_PROBE = 0x3,    /* struct mmiotrace_map */
-	MMIO_UNPROBE = 0x4,  /* struct mmiotrace_map */
-	MMIO_UNKNOWN_OP = 0x5, /* struct mmiotrace_rw */
+	MMIO_READ	= 0x1,	/* struct mmiotrace_rw */
+	MMIO_WRITE	= 0x2,	/* struct mmiotrace_rw */
+	MMIO_PROBE	= 0x3,	/* struct mmiotrace_map */
+	MMIO_UNPROBE	= 0x4,	/* struct mmiotrace_map */
+	MMIO_UNKNOWN_OP = 0x5,	/* struct mmiotrace_rw */
 };
 
 struct mmiotrace_rw {
-	resource_size_t phys;	/* PCI address of register */
-	unsigned long value;
-	unsigned long pc;	/* optional program counter */
-	int map_id;
-	unsigned char opcode;	/* one of MMIO_{READ,WRITE,UNKNOWN_OP} */
-	unsigned char width;	/* size of register access in bytes */
+	resource_size_t	phys;	/* PCI address of register */
+	unsigned long	value;
+	unsigned long	pc;	/* optional program counter */
+	int		map_id;
+	unsigned char	opcode;	/* one of MMIO_{READ,WRITE,UNKNOWN_OP} */
+	unsigned char	width;	/* size of register access in bytes */
 };
 
 struct mmiotrace_map {
-	resource_size_t phys;	/* base address in PCI space */
-	unsigned long virt;	/* base virtual address */
-	unsigned long len;	/* mapping size */
-	int map_id;
-	unsigned char opcode;	/* MMIO_PROBE or MMIO_UNPROBE */
+	resource_size_t	phys;	/* base address in PCI space */
+	unsigned long	virt;	/* base virtual address */
+	unsigned long	len;	/* mapping size */
+	int		map_id;
+	unsigned char	opcode;	/* MMIO_PROBE or MMIO_UNPROBE */
 };
 
 /* in kernel/trace/trace_mmiotrace.c */
@@ -94,4 +110,4 @@ extern void mmio_trace_rw(struct mmiotrace_rw *rw);
 extern void mmio_trace_mapping(struct mmiotrace_map *map);
 extern int mmio_trace_printk(const char *fmt, va_list args);
 
-#endif /* MMIOTRACE_H */
+#endif /* _LINUX_MMIOTRACE_H */