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

1 files changed, 25 insertions, 20 deletions

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);