printk ratelimiting rewrite

All ratelimit user use same jiffies and burst params, so some messages
(callbacks) will be lost.

For example:
a call printk_ratelimit(5 * HZ, 1)
b call printk_ratelimit(5 * HZ, 1) before the 5*HZ timeout of a, then b will
will be supressed.

- rewrite __ratelimit, and use a ratelimit_state as parameter.  Thanks for
  hints from andrew.

- Add WARN_ON_RATELIMIT, update rcupreempt.h

- remove __printk_ratelimit

- use __ratelimit in net_ratelimit

Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Dave Young <hidave.darkstar@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 4 insertions, 5 deletions

diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index a570e2af22cb..f686467ff12b 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -67,7 +67,7 @@ static struct ctl_table net_core_table[] = {
         {
                 .ctl_name       = NET_CORE_MSG_COST,
                 .procname       = "message_cost",
-                .data           = &net_msg_cost,
+                .data           = &net_ratelimit_state.interval,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = &proc_dointvec_jiffies,
@@ -76,7 +76,7 @@ static struct ctl_table net_core_table[] = {
         {
                 .ctl_name       = NET_CORE_MSG_BURST,
                 .procname       = "message_burst",
-                .data           = &net_msg_burst,
+                .data           = &net_ratelimit_state.burst,
                 .maxlen         = sizeof(int),
                 .mode           = 0644,
                 .proc_handler   = &proc_dointvec,
diff --git a/net/core/utils.c b/net/core/utils.c
index 8031eb59054e..72e0ebe964a0 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -31,17 +31,16 @@
 #include <asm/system.h>
 #include <asm/uaccess.h>
 
-int net_msg_cost __read_mostly = 5*HZ;
-int net_msg_burst __read_mostly = 10;
 int net_msg_warn __read_mostly = 1;
 EXPORT_SYMBOL(net_msg_warn);
 
+DEFINE_RATELIMIT_STATE(net_ratelimit_state, 5 * HZ, 10);
 /*
  * All net warning printk()s should be guarded by this function.
  */
 int net_ratelimit(void)
 {
-        return __printk_ratelimit(net_msg_cost, net_msg_burst);
+        return __ratelimit(&net_ratelimit_state);
 }
 EXPORT_SYMBOL(net_ratelimit);