Add ddi_time_after and friends

When comparing times gotten from ddi_get_lbolt, we have to take account of
wrap around of jiffies. Therefore, we cannot use 't1 < t2'. Instead we should
use 't1 - t2 < 0'.

This patch add ddi_time_after and friends to address this issue. They have
strict type restriction, clock_t for vanilla and int64_t for 64 version, to
prevent type conversion from screwing things.

Signed-off-by: Chunwei Chen <tuxoko@gmail.com>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #335

diff --git a/include/sys/timer.h b/include/sys/timer.h
index 2542510dd299574a9d4e1138cd58ca1433be871d..33d577e719aa63643dc5abc655d3d3e85fcb0bdd 100644 (file)
--- a/include/sys/timer.h
+++ b/include/sys/timer.h
@@ -35,6 +35,20 @@
 #define ddi_get_lbolt()                        ((clock_t)jiffies)
 #define ddi_get_lbolt64()              ((int64_t)get_jiffies_64())
 
+#define ddi_time_before(a, b)          (typecheck(clock_t, a) && \
+                                       typecheck(clock_t, b) && \
+                                       ((a) - (b) < 0))
+#define ddi_time_after(a, b)           ddi_time_before(b, a)
+#define ddi_time_before_eq(a, b)       (!ddi_time_after(a, b))
+#define ddi_time_after_eq(a, b)                ddi_time_before_eq(b, a)
+
+#define ddi_time_before64(a, b)                (typecheck(int64_t, a) && \
+                                       typecheck(int64_t, b) && \
+                                       ((a) - (b) < 0))
+#define ddi_time_after64(a, b)         ddi_time_before64(b, a)
+#define ddi_time_before_eq64(a, b)     (!ddi_time_after64(a, b))
+#define ddi_time_after_eq64(a, b)      ddi_time_before_eq64(b, a)
+
 #define delay(ticks)                   schedule_timeout_uninterruptible(ticks)
 
 #define SEC_TO_TICK(sec)               ((sec) * HZ)

diff --git a/module/splat/splat-taskq.c b/module/splat/splat-taskq.c
index e4793d4578dcc074ee32798f3fa218ac816c9486..074af895b2f031b706fe14ea9b44220046683bf1 100644 (file)
--- a/module/splat/splat-taskq.c
+++ b/module/splat/splat-taskq.c
@@ -82,7 +82,7 @@ typedef struct splat_taskq_arg {
        atomic_t *count;
        int order[SPLAT_TASKQ_ORDER_MAX];
        unsigned int depth;
-       unsigned long expire;
+       clock_t expire;
        taskq_t *tq;
        taskq_ent_t *tqe;
        spinlock_t lock;
@@ -1140,7 +1140,7 @@ splat_taskq_test9_func(void *arg)
        splat_taskq_arg_t *tq_arg = (splat_taskq_arg_t *)arg;
        ASSERT(tq_arg);
 
-       if (ddi_get_lbolt() >= tq_arg->expire)
+       if (ddi_time_after_eq(ddi_get_lbolt(), tq_arg->expire))
                atomic_inc(tq_arg->count);
 
        kmem_free(tq_arg, sizeof(splat_taskq_arg_t));
@@ -1228,7 +1228,7 @@ splat_taskq_test10_func(void *arg)
        splat_taskq_arg_t *tq_arg = (splat_taskq_arg_t *)arg;
        uint8_t rnd;
 
-       if (ddi_get_lbolt() >= tq_arg->expire)
+       if (ddi_time_after_eq(ddi_get_lbolt(), tq_arg->expire))
                atomic_inc(tq_arg->count);
 
        /* Randomly sleep to further perturb the system */
@@ -1249,7 +1249,7 @@ splat_taskq_test10(struct file *file, void *arg)
        int canceled = 0;
        int completed = 0;
        int blocked = 0;
-       unsigned long start, cancel;
+       clock_t start, cancel;
 
        tqas = vmalloc(sizeof(*tqas) * nr_tasks);
        if (tqas == NULL)
@@ -1327,7 +1327,7 @@ splat_taskq_test10(struct file *file, void *arg)
        start = ddi_get_lbolt();
        i = 0;
 
-       while (ddi_get_lbolt() < start + 5 * HZ) {
+       while (ddi_time_before(ddi_get_lbolt(), start + 5 * HZ)) {
                taskqid_t id;
                uint32_t rnd;