rcu: Stop overflowing signed integers

The C standard does not specify the result of an operation that
overflows a signed integer, so such operations need to be
avoided.  This patch changes the type of several fields from
"long" to "unsigned long" and adjusts operations as needed.
ULONG_CMP_GE() and ULONG_CMP_LT() macros are introduced to do
the modular comparisons that are appropriate given that overflow
is an expected event.

Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-17-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 7 deletions

diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c
index 9d2c88423b31..d45db2e35d27 100644
--- a/kernel/rcutree_trace.c
+++ b/kernel/rcutree_trace.c
@@ -50,7 +50,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
 {
         if (!rdp->beenonline)
                 return;
-        seq_printf(m, "%3d%cc=%ld g=%ld pq=%d pqc=%ld qp=%d",
+        seq_printf(m, "%3d%cc=%lu g=%lu pq=%d pqc=%lu qp=%d",
                    rdp->cpu,
                    cpu_is_offline(rdp->cpu) ? '!' : ' ',
                    rdp->completed, rdp->gpnum,
@@ -105,7 +105,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
 {
         if (!rdp->beenonline)
                 return;
-        seq_printf(m, "%d,%s,%ld,%ld,%d,%ld,%d",
+        seq_printf(m, "%d,%s,%lu,%lu,%d,%lu,%d",
                    rdp->cpu,
                    cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
                    rdp->completed, rdp->gpnum,
@@ -155,13 +155,13 @@ static const struct file_operations rcudata_csv_fops = {
 
 static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
 {
-        long gpnum;
+        unsigned long gpnum;
         int level = 0;
         int phase;
         struct rcu_node *rnp;
 
         gpnum = rsp->gpnum;
-        seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
+        seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x "
                       "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
                    rsp->completed, gpnum, rsp->signaled,
                    (long)(rsp->jiffies_force_qs - jiffies),
@@ -215,12 +215,12 @@ static const struct file_operations rcuhier_fops = {
 static int show_rcugp(struct seq_file *m, void *unused)
 {
 #ifdef CONFIG_TREE_PREEMPT_RCU
-        seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%ld\n",
+        seq_printf(m, "rcu_preempt: completed=%ld  gpnum=%lu\n",
                    rcu_preempt_state.completed, rcu_preempt_state.gpnum);
 #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-        seq_printf(m, "rcu_sched: completed=%ld  gpnum=%ld\n",
+        seq_printf(m, "rcu_sched: completed=%ld  gpnum=%lu\n",
                    rcu_sched_state.completed, rcu_sched_state.gpnum);
-        seq_printf(m, "rcu_bh: completed=%ld  gpnum=%ld\n",
+        seq_printf(m, "rcu_bh: completed=%ld  gpnum=%lu\n",
                    rcu_bh_state.completed, rcu_bh_state.gpnum);
         return 0;
 }