2014-06-20 07:05:44

by Vladimir Kondratiev

[permalink] [raw]
Subject: [PATCH] wil6210: fix for 64-bit integer division

On some platforms, cycles_t is 64-bit, and gcc generates call to
__udivdi3 for straight division of cycles_t/cycles_t. This leads
to compilation failure, as this function is not exist in the kernel
runtime. do_div() to rescue

Original report:

tree: git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next.git master
head: 2e91606f5e1ec7329557dfc0e298c4c021acbb80
commit: 7c0acf868d2e470c9d6a40091acf8d6444c01b57 [81/103] wil6210: Tx performance monitoring
config: i386-randconfig-ha3-0620 (attached as .config)

All error/warnings:

drivers/built-in.o: In function `wil_vring_debugfs_show':
>> debugfs.c:(.text+0x39b9be): undefined reference to `__udivdi3'

Signed-off-by: Vladimir Kondratiev <[email protected]>
---
drivers/net/wireless/ath/wil6210/debugfs.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/wil6210/debugfs.c b/drivers/net/wireless/ath/wil6210/debugfs.c
index 7d1ef4e..a868c5e 100644
--- a/drivers/net/wireless/ath/wil6210/debugfs.c
+++ b/drivers/net/wireless/ath/wil6210/debugfs.c
@@ -83,9 +83,10 @@ static int wil_vring_debugfs_show(struct seq_file *s, void *data)
char name[10];
/* performance monitoring */
cycles_t now = get_cycles();
- cycles_t idle = txdata->idle;
+ cycles_t idle = txdata->idle * 100;
cycles_t total = now - txdata->begin;

+ do_div(idle, total);
txdata->begin = now;
txdata->idle = 0ULL;

@@ -93,7 +94,7 @@ static int wil_vring_debugfs_show(struct seq_file *s, void *data)

seq_printf(s, "\n%pM CID %d TID %d [%3d|%3d] idle %3d%%\n",
wil->sta[cid].addr, cid, tid, used, avail,
- (int)((idle*100)/total));
+ (int)idle);

wil_print_vring(s, wil, name, vring, '_', 'H');
}
--
1.9.1