__UNIQUE_ID()

Jan Beulich points out __COUNTER__ (gcc 4.3 and above), so let's use that to create unique ids. This is better than __LINE__ which we use today, so provide a wrapper. Stanislaw Gruszka <[email protected]> reported that some module parameters start with a digit, so we need to prepend when we for the unique id. Signed-off-by: Rusty Russell <[email protected]> Acked-by: Jan Beulich <[email protected]>
ixin · Dec 14, 2012 · 6f33d58 · 6f33d58
1 parent d890f51
commit 6f33d58
Show file tree

Hide file tree

Showing 2 changed files with 11 additions and 0 deletions.
diff --git a/include/linux/compiler-gcc4.h b/include/linux/compiler-gcc4.h
@@ -31,6 +31,8 @@
 
 #define __linktime_error(message) __attribute__((__error__(message)))
 
+#define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __COUNTER__)
+
 #if __GNUC_MINOR__ >= 5
 /*
  * Mark a position in code as unreachable.  This can be used to

diff --git a/include/linux/compiler.h b/include/linux/compiler.h
@@ -42,6 +42,10 @@ extern void __chk_io_ptr(const volatile void __iomem *);
 # define __rcu
 #endif
 
+/* Indirect macros required for expanded argument pasting, eg. __LINE__. */
+#define ___PASTE(a,b) a##b
+#define __PASTE(a,b) ___PASTE(a,b)
+
 #ifdef __KERNEL__
 
 #ifdef __GNUC__
@@ -164,6 +168,11 @@ void ftrace_likely_update(struct ftrace_branch_data *f, int val, int expect);
     (typeof(ptr)) (__ptr + (off)); })
 #endif
 
+/* Not-quite-unique ID. */
+#ifndef __UNIQUE_ID
+# define __UNIQUE_ID(prefix) __PASTE(__PASTE(__UNIQUE_ID_, prefix), __LINE__)
+#endif
+
 #endif /* __KERNEL__ */
 
 #endif /* __ASSEMBLY__ */