[PATCH] Fix ptrace in the vsyscall dso area

From: Roland McGrath <roland@redhat.com>

The #include is the part of this patch that matters, so the #ifdef below
works.

The rest of the patch removes gratuitous duplication due to some strange
aversion to concision in the presence of #ifdef, the kind that is all too
common, utterly pointless, and error prone.

include/linux/mm.h

@@ -12,6 +12,7 @@
 #include <linux/mmzone.h>
 #include <linux/rbtree.h>
 #include <linux/fs.h>
+#include <linux/elf.h>
 
 #ifndef CONFIG_DISCONTIGMEM          /* Don't use mapnrs, do it properly */
 extern unsigned long max_mapnr;
@@ -643,31 +644,24 @@ kernel_map_pages(struct page *page, int numpages, int enable)
 #endif
 
 #ifndef CONFIG_ARCH_GATE_AREA
-#ifdef AT_SYSINFO_EHDR
 static inline int in_gate_area(struct task_struct *task, unsigned long addr)
 {
+#ifdef AT_SYSINFO_EHDR
 	if ((addr >= FIXADDR_USER_START) && (addr < FIXADDR_USER_END))
 		return 1;
-	else
-		return 0;
+#endif
+	return 0;
 }
 
 extern struct vm_area_struct gate_vma;
 static inline struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
 {
+#ifdef AT_SYSINFO_EHDR
 	return &gate_vma;
-}
 #else
-static inline int in_gate_area(struct task_struct *task, unsigned long addr)
-{
 	return 0;
-}
-
-static inline struct vm_area_struct *get_gate_vma(struct task_struct *tsk)
-{
-	return NULL;
-}
 #endif
+}
 #endif
 
 #endif /* __KERNEL__ */