[Xen-changelog] NS_PER_TICK must be a s64 quantity. It is compared with

[Xen patchbot -unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kaf24@xxxxxxxxxxxxxxxxxxxx
# Node ID 9e373ffff3e659e665b6df702c44c1db3598742e
# Parent  48f542f8d906f988b6d7ffc0c5d44f5a9dfc8a31
NS_PER_TICK must be a s64 quantity. It is compared with
possibly -ve values which we do not want to 'promote' to
big +ve values.

Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>

diff -r 48f542f8d906 -r 9e373ffff3e6 
linux-2.6-xen-sparse/arch/xen/i386/kernel/time.c
--- a/linux-2.6-xen-sparse/arch/xen/i386/kernel/time.c  Thu Oct 13 07:06:27 2005
+++ b/linux-2.6-xen-sparse/arch/xen/i386/kernel/time.c  Thu Oct 13 07:38:49 2005
@@ -122,7 +122,8 @@
 static u64 processed_system_time;   /* System time (ns) at last processing. */
 static DEFINE_PER_CPU(u64, processed_system_time);
 
-#define NS_PER_TICK (1000000000ULL/HZ)
+/* Must be signed, as it's compared with s64 quantities which can be -ve. */
+#define NS_PER_TICK (1000000000LL/HZ)
 
 static inline void __normalize_time(time_t *sec, s64 *nsec)
 {
@@ -235,9 +236,9 @@
 
        /* Adjust wall-clock time base based on wall_jiffies ticks. */
        wc_nsec = processed_system_time;
-       wc_nsec += (u64)sec * 1000000000ULL;
-       wc_nsec += (u64)nsec;
-       wc_nsec -= (jiffies - wall_jiffies) * (u64)(NSEC_PER_SEC / HZ);
+       wc_nsec += sec * (u64)NSEC_PER_SEC;
+       wc_nsec += nsec;
+       wc_nsec -= (jiffies - wall_jiffies) * (u64)NS_PER_TICK;
 
        /* Split wallclock base into seconds and nanoseconds. */
        tmp = wc_nsec;
@@ -437,7 +438,7 @@
         * be stale, so we can retry with fresh ones.
         */
        for ( ; ; ) {
-               nsec = (s64)tv->tv_nsec - (s64)get_nsec_offset(shadow);
+               nsec = tv->tv_nsec - get_nsec_offset(shadow);
                if (time_values_up_to_date(cpu))
                        break;
                get_time_values_from_xen();
@@ -558,7 +559,7 @@
        }
        while (!time_values_up_to_date(cpu));
 
-       if (unlikely(delta < (s64)-1000000) || unlikely(delta_cpu < 0)) {
+       if (unlikely(delta < -1000000LL) || unlikely(delta_cpu < 0)) {
                printk("Timer ISR/%d: Time went backwards: "
                       "delta=%lld cpu_delta=%lld shadow=%lld "
                       "off=%lld processed=%lld cpu_processed=%lld\n",
@@ -802,7 +803,7 @@
                 * but that's ok: we'll just end up with a shorter timeout. */
                if (delta < 1) 
                        delta = 1;
-               st = processed_system_time + ((u64)delta * NS_PER_TICK);
+               st = processed_system_time + (delta * (u64)NS_PER_TICK);
        } while (read_seqretry(&xtime_lock, seq));
 
        return st;

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