timer: Fix jiffies wrap behavior of round_jiffies_common()
Bart Van Assche [Tue, 21 May 2013 18:43:50 +0000 (20:43 +0200)]
commit 9e04d3804d3ac97d8c03a41d78d0f0674b5d01e1 upstream.

Direct compare of jiffies related values does not work in the wrap
around case. Replace it with time_is_after_jiffies().

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: http://lkml.kernel.org/r/519BC066.5080600@acm.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/timer.c

index dd93d90..7e0a770 100644 (file)
@@ -145,9 +145,11 @@ static unsigned long round_jiffies_common(unsigned long j, int cpu,
        /* now that we have rounded, subtract the extra skew again */
        j -= cpu * 3;
 
-       if (j <= jiffies) /* rounding ate our timeout entirely; */
-               return original;
-       return j;
+       /*
+        * Make sure j is still in the future. Otherwise return the
+        * unmodified value.
+        */
+       return time_is_after_jiffies(j) ? j : original;
 }
 
 /**