2015-06-07 10:44:01

by Nicholas Mc Guire

Subject: [PATCH V2] wan: dscc4: use msecs_to_jiffies for conversions

API compliance scanning with coccinelle flagged:
./drivers/net/wan/dscc4.c:1036:1-33:
WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:554:2-34:
WARNING: timeout (10) seems HZ dependent
./drivers/net/wan/dscc4.c:599:2-34:
WARNING: timeout (10) seems HZ dependent

Numeric constants passed to schedule_timeout_*() make the effective
timeout HZ dependent which does not seem to be the intent here.
Fixed up by converting the constant to jiffies with msecs_to_jiffies(),
passing 100ms (assuming HZ==100 in the original code).

Signed-off-by: Nicholas Mc Guire <[email protected]>
---

V2: As the intended timeout is not documented and msecs_to_jiffies(10) may
be a factor 10 off from constant 10, the value is transformed assuming
HZ=100 to be on the safe side as suggested by David Miller
<[email protected]> to minimize the probability of breaking this
old code.

Patch was compile tested with x86_64_defconfig + CONFIG_WAN=y
CONFIG_HDLC=m, CONFIG_DSCC4=m

Patch is against 4.1-rc6 (localversion-next is -next-20150605)

drivers/net/wan/dscc4.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wan/dscc4.c b/drivers/net/wan/dscc4.c
index 0822356..2ce5249 100644
--- a/drivers/net/wan/dscc4.c
+++ b/drivers/net/wan/dscc4.c
@@ -551,7 +551,7 @@ static int dscc4_wait_ack_cec(struct dscc4_dev_priv *dpriv,
msg, i);
goto done;
}
- schedule_timeout_uninterruptible(10);
+ schedule_timeout_uninterruptible(msecs_to_jiffies(100));
rmb();
} while (++i > 0);
netdev_err(dev, "%s timeout\n", msg);
@@ -596,7 +596,7 @@ static inline int dscc4_xpr_ack(struct dscc4_dev_priv *dpriv)
(dpriv->iqtx[cur] & cpu_to_le32(Xpr)))
break;
smp_rmb();
- schedule_timeout_uninterruptible(10);
+ schedule_timeout_uninterruptible(msecs_to_jiffies(100));
} while (++i > 0);

return (i >= 0 ) ? i : -EAGAIN;
@@ -1033,7 +1033,7 @@ static void dscc4_pci_reset(struct pci_dev *pdev, void __iomem *ioaddr)
/* Flush posted writes */
readl(ioaddr + GSTAR);

- schedule_timeout_uninterruptible(10);
+ schedule_timeout_uninterruptible(msecs_to_jiffies(100));

for (i = 0; i < 16; i++)
pci_write_config_dword(pdev, i << 2, dscc4_pci_config_store[i]);
--
1.7.10.4

2015-06-08 06:46:33

by David Miller

Subject: Re: [PATCH V2] wan: dscc4: use msecs_to_jiffies for conversions

From: Nicholas Mc Guire <[email protected]>
Date: Sun, 7 Jun 2015 12:35:46 +0200

> API compliance scanning with coccinelle flagged:
> ./drivers/net/wan/dscc4.c:1036:1-33:
> WARNING: timeout (10) seems HZ dependent
> ./drivers/net/wan/dscc4.c:554:2-34:
> WARNING: timeout (10) seems HZ dependent
> ./drivers/net/wan/dscc4.c:599:2-34:
> WARNING: timeout (10) seems HZ dependent
>
> Numeric constants passed to schedule_timeout_*() make the effective
> timeout HZ dependent which does not seem to be the intent here.
> Fixed up by converting the constant to jiffies with msecs_to_jiffies(),
> passing 100ms (assuming HZ==100 in the original code).
>
> Signed-off-by: Nicholas Mc Guire <[email protected]>

Applied.