[PATCH 4.5 024/101] net: Implement net_dbg_ratelimited() for CONFIG_DYNAMIC_DEBUG case

Greg Kroah-Hartman
2016-05-17T01:46:39Z

From: Tim Bingham <tbingham@akamai.com>

[ Upstream commit 2c94b53738549d81dc7464a32117d1f5112c64d3 ]

Prior to commit d92cff89a0c8 ("net_dbg_ratelimited: turn into no-op
when !DEBUG") the implementation of net_dbg_ratelimited() was buggy
for both the DEBUG and CONFIG_DYNAMIC_DEBUG cases.

The bug was that net_ratelimit() was being called and, despite
returning true, nothing was being printed to the console. This
resulted in messages like the following -

"net_ratelimit: %d callbacks suppressed"

with no other output nearby.

After commit d92cff89a0c8 ("net_dbg_ratelimited: turn into no-op when
!DEBUG") the bug is fixed for the DEBUG case. However, there's no
output at all for CONFIG_DYNAMIC_DEBUG case.

This patch restores debug output (if enabled) for the
CONFIG_DYNAMIC_DEBUG case.

Add a definition of net_dbg_ratelimited() for the CONFIG_DYNAMIC_DEBUG
case. The implementation takes care to check that dynamic debugging is
enabled before calling net_ratelimit().

Fixes: d92cff89a0c8 ("net_dbg_ratelimited: turn into no-op when !DEBUG")
Signed-off-by: Tim Bingham <tbingham@akamai.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
include/linux/net.h | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -245,7 +245,15 @@ do { \
net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__)
#define net_info_ratelimited(fmt, ...) \
net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__)
-#if defined(DEBUG)
+#if defined(CONFIG_DYNAMIC_DEBUG)
+#define net_dbg_ratelimited(fmt, ...) \
+do { \
+ DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \
+ if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT) && \
+ net_ratelimit()) \
+ __dynamic_pr_debug(&descriptor, fmt, ##__VA_ARGS__); \
+} while (0)
+#elif defined(DEBUG)
#define net_dbg_ratelimited(fmt, ...) \
net_ratelimited_function(pr_debug, fmt, ##__VA_ARGS__)
#else