Re: [PATCH] drivers/net: Fix potential incorrect call for udelay()

From: tingwei liu
Date: Mon Dec 23 2013 - 22:22:41 EST


On Mon, Dec 23, 2013 at 5:33 PM, Libin <huawei.libin@xxxxxxxxxx> wrote:
>
> From: Li Bin <huawei.libin@xxxxxxxxxx>
>
> The variable delay_time as a module parameter can be set a value
> exceeding the limit of the udelay function. This patch checks the
> delay_time value to select mdelay() or udelay().
>
> Signed-off-by: Li Bin <huawei.libin@xxxxxxxxxx>
> ---
> drivers/net/ethernet/8390/pcnet_cs.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/8390/pcnet_cs.c b/drivers/net/ethernet/8390/pcnet_cs.c
> index 46c5aad..29fe157 100644
> --- a/drivers/net/ethernet/8390/pcnet_cs.c
> +++ b/drivers/net/ethernet/8390/pcnet_cs.c
> @@ -1284,8 +1284,12 @@ static void dma_block_output(struct net_device *dev, int count,
> }
>
> outb_p(ENISR_RDC, nic_base + EN0_ISR); /* Ack intr. */
> - if (info->flags & DELAY_OUTPUT)
> - udelay((long)delay_time);
> + if (info->flags & DELAY_OUTPUT) {
> + if (delay_time >= 1000)
> + mdelay((long)delay_time/1000);

Indeed use of mdelay is discouraged.
I prefer to limit delay_time less than 1000.

Tingwei
>
> + else
> + udelay(delay_time);
> + }
> ei_status.dmaing &= ~0x01;
> }
>
> --
> 1.8.2.2
>
>
> --
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