linux-kernel - [PATCH] devlink: Use DIV_ROUND_UP_ULL in DEVLINK_HEALTH_SIZE_TO

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Date:   Mon, 21 Jan 2019 21:23:01 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Jiri Pirko <jiri@...lanox.com>,
        "David S. Miller" <davem@...emloft.net>
Cc:     Eran Ben Elisha <eranbe@...lanox.com>,
        Moshe Shemesh <moshe@...lanox.com>, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] devlink: Use DIV_ROUND_UP_ULL in DEVLINK_HEALTH_SIZE_TO_BUFFERS

When building this code on a 32-bit platform such as ARM, there is a
link time error (lld error shown, happpens with ld.bfd too):

ld.lld: error: undefined symbol: __aeabi_uldivmod
>>> referenced by devlink.c
>>>               net/core/devlink.o:(devlink_health_buffers_create) in archive built-in.a

This happens when using a regular division symbol with a u64 dividend.
Use DIV_ROUND_UP_ULL, which wraps do_div, to avoid this situation.

Fixes: cb5ccfbe73b3 ("devlink: Add health buffer support")
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 net/core/devlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 60248a53c0ad..9ee25dfbc09d 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3599,7 +3599,7 @@ static int devlink_nl_cmd_region_read_dumpit(struct sk_buff *skb,
 
 #define DEVLINK_HEALTH_BUFFER_SIZE (4096 - GENL_HDRLEN)
 #define DEVLINK_HEALTH_BUFFER_DATA_SIZE (DEVLINK_HEALTH_BUFFER_SIZE / 2)
-#define DEVLINK_HEALTH_SIZE_TO_BUFFERS(size) DIV_ROUND_UP(size, DEVLINK_HEALTH_BUFFER_DATA_SIZE)
+#define DEVLINK_HEALTH_SIZE_TO_BUFFERS(size) DIV_ROUND_UP_ULL(size, DEVLINK_HEALTH_BUFFER_DATA_SIZE)
 #define DEVLINK_HEALTH_BUFFER_MAX_CHUNK 1024
 
 struct devlink_health_buffer {
-- 
2.20.1