[PATCH 5/9 V2] idr: covert BUG_ON() to WARN_ON_ONCE() if the argument is invalid.

[Lai Jiangshan <laijs@cn.fujitsu.com>]

When the arguments passed by the caller are invalid, WARN_ON_ONCE()
is proper than BUG_ON() which may crash the kernel.

The invalid-checking for ida_simple_remove() is moved into ida_remove().
idr_remove() also adds this WARN_ON_ONCE().

And when "end < start" in ida_simple_get(), it returns -ENOSPC as
ida_alloc() does.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 lib/idr.c |   13 ++++++++-----
 1 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/lib/idr.c b/lib/idr.c
index e79e051..317fd35 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -559,7 +559,7 @@ void idr_remove(struct idr *idp, int id)
 	struct idr_layer *p;
 	struct idr_layer *to_free;
 
-	if (id < 0)
+	if (WARN_ON_ONCE(id < 0))
 		return;
 
 	if (id > idr_max(idp->layers)) {
@@ -1030,6 +1030,9 @@ void ida_remove(struct ida *ida, int id)
 	int n;
 	struct ida_bitmap *bitmap;
 
+	if (WARN_ON_ONCE(id < 0))
+		return;
+
 	if (idr_id > idr_max(ida->idr.layers))
 		goto err;
 
@@ -1096,13 +1099,14 @@ int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
 	unsigned int max;
 	unsigned long flags;
 
-	BUG_ON((int)start < 0);
-	BUG_ON((int)end < 0);
+	if (WARN_ON_ONCE(((int)start < 0) || ((int)end < 0)))
+		return -EINVAL;
 
 	if (end == 0)
 		max = 0x80000000;
 	else {
-		BUG_ON(end < start);
+		if (WARN_ON_ONCE(end < start))
+			return -ENOSPC;
 		max = end - 1;
 	}
 
@@ -1138,7 +1142,6 @@ void ida_simple_remove(struct ida *ida, unsigned int id)
 {
 	unsigned long flags;
 
-	BUG_ON((int)id < 0);
 	spin_lock_irqsave(&simple_ida_lock, flags);
 	ida_remove(ida, id);
 	spin_unlock_irqrestore(&simple_ida_lock, flags);
-- 
1.7.4.4