[PATCH 13/22] dynamic_debug: refactor dynamic_pr_debug and friends

From: Rasmus Villemoes
Date: Wed Sep 19 2018 - 18:05:11 EST


For the upcoming 'define the _ddebug descriptor in assembly', we need
all the descriptors in a translation unit to have distinct
names (because asm does not understand C scope). The easiest way to
achieve that is as usual with an extra level of macros, passing the
identifier to use to the innermost macro, generating it via __UNIQUE_ID
or something.

However, instead of repeating that exercise for dynamic_pr_debug,
dynamic_dev_dbg, dynamic_netdev_dbg and dynamic_hex_dump separately, we
can use the similarity between their bodies to implement them via a
common macro, _dynamic_func_call - though the hex_dump case requires
a slight variant, since print_hex_dump does not take the _ddebug
descriptor. We'll also get to use that variant elsewhere (btrfs).

Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
---
include/linux/dynamic_debug.h | 72 ++++++++++++++++++++++++++-----------------
1 file changed, 43 insertions(+), 29 deletions(-)

diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index 6a002b789d51..b9424097df37 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -112,40 +112,54 @@ void __dynamic_netdev_dbg(struct _ddebug *descriptor,

#endif

-#define dynamic_pr_debug(fmt, ...) \
-do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
- if (DYNAMIC_DEBUG_BRANCH(descriptor)) \
- __dynamic_pr_debug(&descriptor, pr_fmt(fmt), \
- ##__VA_ARGS__); \
+#define __dynamic_func_call(id, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
+ if (DYNAMIC_DEBUG_BRANCH(id)) \
+ func(&id, ##__VA_ARGS__); \
} while (0)

-#define dynamic_dev_dbg(dev, fmt, ...) \
-do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
- if (DYNAMIC_DEBUG_BRANCH(descriptor)) \
- __dynamic_dev_dbg(&descriptor, dev, fmt, \
- ##__VA_ARGS__); \
+#define __dynamic_func_call_no_desc(id, fmt, func, ...) do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA(id, fmt); \
+ if (DYNAMIC_DEBUG_BRANCH(id)) \
+ func(__VA_ARGS__); \
} while (0)

-#define dynamic_netdev_dbg(dev, fmt, ...) \
-do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
- if (DYNAMIC_DEBUG_BRANCH(descriptor)) \
- __dynamic_netdev_dbg(&descriptor, dev, fmt, \
- ##__VA_ARGS__); \
-} while (0)
+/*
+ * "Factory macro" for generating a call to func, guarded by a
+ * DYNAMIC_DEBUG_BRANCH. The dynamic debug decriptor will be
+ * initialized using the fmt argument. The function will be called with
+ * the address of the descriptor as first argument, followed by all
+ * the varargs. Note that fmt is repeated in invocations of this
+ * macro.
+ */
+#define _dynamic_func_call(fmt, func, ...) \
+ __dynamic_func_call(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)
+/*
+ * A variant that does the same, except that the descriptor is not
+ * passed as the first argument to the function; it is only called
+ * with precisely the macro's varargs.
+ */
+#define _dynamic_func_call_no_desc(fmt, func, ...) \
+ __dynamic_func_call_no_desc(__UNIQUE_ID(ddebug), fmt, func, ##__VA_ARGS__)

-#define dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
- groupsize, buf, len, ascii) \
-do { \
- DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, \
- __builtin_constant_p(prefix_str) ? prefix_str : "hexdump");\
- if (DYNAMIC_DEBUG_BRANCH(descriptor)) \
- print_hex_dump(KERN_DEBUG, prefix_str, \
- prefix_type, rowsize, groupsize, \
- buf, len, ascii); \
-} while (0)
+#define dynamic_pr_debug(fmt, ...) \
+ _dynamic_func_call(fmt, __dynamic_pr_debug, \
+ pr_fmt(fmt), ##__VA_ARGS__)
+
+#define dynamic_dev_dbg(dev, fmt, ...) \
+ _dynamic_func_call(fmt,__dynamic_dev_dbg, \
+ dev, fmt, ##__VA_ARGS__)
+
+#define dynamic_netdev_dbg(dev, fmt, ...) \
+ _dynamic_func_call(fmt, __dynamic_netdev_dbg, \
+ dev, fmt, ##__VA_ARGS__)
+
+#define dynamic_hex_dump(prefix_str, prefix_type, rowsize, \
+ groupsize, buf, len, ascii) \
+ _dynamic_func_call_no_desc(__builtin_constant_p(prefix_str) ? prefix_str : "hexdump", \
+ print_hex_dump, \
+ KERN_DEBUG, prefix_str, prefix_type, \
+ rowsize, groupsize, buf, len, ascii)

#else

--
2.16.4