[PATCH v3] ocfs2: heartbeat: replace simple_strtoul with kstrtoul

[Daniel Yang <danielyangkang@gmail.com>]

The function simple_strtoul is deprecated due to ignoring overflows and
also requires clunkier error checking. Replacing with kstrtoul() leads
to safer code and cleaner error checking.

Signed-off-by: Daniel Yang <danielyangkang@gmail.com>
---
v2->v3: code style change and return ret
v1->v2: moved ret definition and removed blank lines

 fs/ocfs2/cluster/heartbeat.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index dff18efbc..76f1e7bfd 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -1536,10 +1536,11 @@ static int o2hb_read_block_input(struct o2hb_region *reg,
 {
 	unsigned long bytes;
 	char *p = (char *)page;
+	int ret;
 
-	bytes = simple_strtoul(p, &p, 0);
-	if (!p || (*p && (*p != '\n')))
-		return -EINVAL;
+	ret = kstrtoul(p, 0, &bytes);
+	if (ret)
+		return ret;
 
 	/* Heartbeat and fs min / max block sizes are the same. */
 	if (bytes > 4096 || bytes < 512)
@@ -1623,13 +1624,14 @@ static ssize_t o2hb_region_blocks_store(struct config_item *item,
 	struct o2hb_region *reg = to_o2hb_region(item);
 	unsigned long tmp;
 	char *p = (char *)page;
+	int ret;
 
 	if (reg->hr_bdev_file)
 		return -EINVAL;
 
-	tmp = simple_strtoul(p, &p, 0);
-	if (!p || (*p && (*p != '\n')))
-		return -EINVAL;
+	ret = kstrtoul(p, 0, &tmp);
+	if (ret)
+		return ret;
 
 	if (tmp > O2NM_MAX_NODES || tmp == 0)
 		return -ERANGE;
@@ -2141,10 +2143,11 @@ static ssize_t o2hb_heartbeat_group_dead_threshold_store(struct config_item *ite
 {
 	unsigned long tmp;
 	char *p = (char *)page;
+	int ret;
 
-	tmp = simple_strtoul(p, &p, 10);
-	if (!p || (*p && (*p != '\n')))
-                return -EINVAL;
+	ret = kstrtoul(p, 10, &tmp);
+	if (ret)
+		return ret;
 
 	/* this will validate ranges for us. */
 	o2hb_dead_threshold_set((unsigned int) tmp);
-- 
2.39.5