Merge branch 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'core-printk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  ratelimit: Make suppressed output messages more useful
  printk: Remove ratelimit.h from kernel.h
  ratelimit: Fix/allow use in atomic contexts
  ratelimit: Use per ratelimit context locking

8 files changed, 61 insertions, 37 deletions

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index f4e3184fa054..3fa4c590cf12 100644
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -15,7 +15,6 @@
 #include <linux/bitops.h>
 #include <linux/log2.h>
 #include <linux/typecheck.h>
-#include <linux/ratelimit.h>
 #include <linux/dynamic_debug.h>
 #include <asm/byteorder.h>
 #include <asm/bug.h>
@@ -241,8 +240,8 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 asmlinkage int printk(const char * fmt, ...)
         __attribute__ ((format (printf, 1, 2))) __cold;
 
-extern struct ratelimit_state printk_ratelimit_state;
-extern int printk_ratelimit(void);
+extern int __printk_ratelimit(const char *func);
+#define printk_ratelimit() __printk_ratelimit(__func__)
 extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
                                    unsigned int interval_msec);
 
diff --git a/include/linux/net.h b/include/linux/net.h
index 529a0931711d..d7e26e30c8c2 100644
--- a/include/linux/net.h
+++ b/include/linux/net.h
@@ -358,6 +358,7 @@ static const struct proto_ops name##_ops = {			\
 
 #ifdef CONFIG_SYSCTL
 #include <linux/sysctl.h>
+#include <linux/ratelimit.h>
 extern struct ratelimit_state net_ratelimit_state;
 #endif
 
diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h
index 00044b856453..668cf1bef030 100644
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -1,20 +1,31 @@
 #ifndef _LINUX_RATELIMIT_H
 #define _LINUX_RATELIMIT_H
+
 #include <linux/param.h>
+#include <linux/spinlock_types.h>
 
-#define DEFAULT_RATELIMIT_INTERVAL (5 * HZ)
-#define DEFAULT_RATELIMIT_BURST 10
+#define DEFAULT_RATELIMIT_INTERVAL      (5 * HZ)
+#define DEFAULT_RATELIMIT_BURST         10
 
 struct ratelimit_state {
-        int interval;
-        int burst;
-        int printed;
-        int missed;
-        unsigned long begin;
+        spinlock_t      lock;           /* protect the state */
+
+        int             interval;
+        int             burst;
+        int             printed;
+        int             missed;
+        unsigned long   begin;
 };
 
-#define DEFINE_RATELIMIT_STATE(name, interval, burst)           \
-                struct ratelimit_state name = {interval, burst,}
+#define DEFINE_RATELIMIT_STATE(name, interval_init, burst_init)         \
+                                                                        \
+        struct ratelimit_state name = {                                 \
+                .lock           = __SPIN_LOCK_UNLOCKED(name.lock),      \
+                .interval       = interval_init,                        \
+                .burst          = burst_init,                           \
+        }
+
+extern int ___ratelimit(struct ratelimit_state *rs, const char *func);
+#define __ratelimit(state) ___ratelimit(state, __func__)
 
-extern int __ratelimit(struct ratelimit_state *rs);
-#endif
+#endif /* _LINUX_RATELIMIT_H */
diff --git a/kernel/printk.c b/kernel/printk.c
index f38b07f78a4e..b5ac4d99c667 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -33,6 +33,7 @@
 #include <linux/bootmem.h>
 #include <linux/syscalls.h>
 #include <linux/kexec.h>
+#include <linux/ratelimit.h>
 
 #include <asm/uaccess.h>
 
@@ -1376,11 +1377,11 @@ late_initcall(disable_boot_consoles);
  */
 DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10);
 
-int printk_ratelimit(void)
+int __printk_ratelimit(const char *func)
 {
-        return __ratelimit(&printk_ratelimit_state);
+        return ___ratelimit(&printk_ratelimit_state, func);
 }
-EXPORT_SYMBOL(printk_ratelimit);
+EXPORT_SYMBOL(__printk_ratelimit);
 
 /**
  * printk_timed_ratelimit - caller-controlled printk ratelimiting
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 0d949c517412..4dbf93a52ee9 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -36,6 +36,7 @@
 #include <linux/sysrq.h>
 #include <linux/highuid.h>
 #include <linux/writeback.h>
+#include <linux/ratelimit.h>
 #include <linux/hugetlb.h>
 #include <linux/initrd.h>
 #include <linux/key.h>
@@ -158,6 +159,8 @@ extern int no_unaligned_warning;
 extern int unaligned_dump_stack;
 #endif
 
+extern struct ratelimit_state printk_ratelimit_state;
+
 #ifdef CONFIG_RT_MUTEXES
 extern int max_lock_depth;
 #endif
diff --git a/lib/ratelimit.c b/lib/ratelimit.c
index 26187edcc7ea..09f5ce1810dc 100644
--- a/lib/ratelimit.c
+++ b/lib/ratelimit.c
@@ -7,15 +7,12 @@
  * parameter. Now every user can use their own standalone ratelimit_state.
  *
  * This file is released under the GPLv2.
- *
  */
 
-#include <linux/kernel.h>
+#include <linux/ratelimit.h>
 #include <linux/jiffies.h>
 #include <linux/module.h>
 
-static DEFINE_SPINLOCK(ratelimit_lock);
-
 /*
  * __ratelimit - rate limiting
  * @rs: ratelimit_state data
@@ -23,35 +20,43 @@ static DEFINE_SPINLOCK(ratelimit_lock);
  * This enforces a rate limit: not more than @rs->ratelimit_burst callbacks
  * in every @rs->ratelimit_jiffies
  */
-int __ratelimit(struct ratelimit_state *rs)
+int ___ratelimit(struct ratelimit_state *rs, const char *func)
 {
         unsigned long flags;
+        int ret;
 
         if (!rs->interval)
                 return 1;
 
-        spin_lock_irqsave(&ratelimit_lock, flags);
+        /*
+         * If we contend on this state's lock then almost
+         * by definition we are too busy to print a message,
+         * in addition to the one that will be printed by
+         * the entity that is holding the lock already:
+         */
+        if (!spin_trylock_irqsave(&rs->lock, flags))
+                return 1;
+
         if (!rs->begin)
                 rs->begin = jiffies;
 
         if (time_is_before_jiffies(rs->begin + rs->interval)) {
                 if (rs->missed)
                         printk(KERN_WARNING "%s: %d callbacks suppressed\n",
-                                __func__, rs->missed);
-                rs->begin = 0;
+                                func, rs->missed);
+                rs->begin   = 0;
                 rs->printed = 0;
-                rs->missed = 0;
+                rs->missed  = 0;
         }
-        if (rs->burst && rs->burst > rs->printed)
-                goto print;
-
-        rs->missed++;
-        spin_unlock_irqrestore(&ratelimit_lock, flags);
-        return 0;
+        if (rs->burst && rs->burst > rs->printed) {
+                rs->printed++;
+                ret = 1;
+        } else {
+                rs->missed++;
+                ret = 0;
+        }
+        spin_unlock_irqrestore(&rs->lock, flags);
 
-print:
-        rs->printed++;
-        spin_unlock_irqrestore(&ratelimit_lock, flags);
-        return 1;
+        return ret;
 }
-EXPORT_SYMBOL(__ratelimit);
+EXPORT_SYMBOL(___ratelimit);
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index 7db1de0497c6..887c03c4e3c6 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -10,7 +10,9 @@
 #include <linux/module.h>
 #include <linux/socket.h>
 #include <linux/netdevice.h>
+#include <linux/ratelimit.h>
 #include <linux/init.h>
+
 #include <net/ip.h>
 #include <net/sock.h>
 
diff --git a/net/core/utils.c b/net/core/utils.c
index 83221aee7084..838250241d26 100644
--- a/net/core/utils.c
+++ b/net/core/utils.c
@@ -24,6 +24,8 @@
 #include <linux/types.h>
 #include <linux/percpu.h>
 #include <linux/init.h>
+#include <linux/ratelimit.h>
+
 #include <net/sock.h>
 
 #include <asm/byteorder.h>