[PATCH] drivers: staging: dgrp: type issue, unsigned number decreasing unsigned number will always be >= 0
Greg KH
gregkh at linuxfoundation.org
Wed Jun 5 22:30:28 UTC 2013
On Wed, Jun 05, 2013 at 08:58:27AM +0800, Chen Gang wrote:
>
> The original author wanted to 'compare' between 'jiffies' and
> 'ch->ch_waketime', but both of them are unsigned, so the original
> 'comparation' is always true.
>
> The related warning (with 'EXTRA_CFLAGS=-W')
> drivers/staging/dgrp/dgrp_net_ops.c:1610:10: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
>
>
> Signed-off-by: Chen Gang <gang.chen at asianux.com>
> ---
> drivers/staging/dgrp/dgrp_net_ops.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/staging/dgrp/dgrp_net_ops.c b/drivers/staging/dgrp/dgrp_net_ops.c
> index 7a0d72d..120c55a 100644
> --- a/drivers/staging/dgrp/dgrp_net_ops.c
> +++ b/drivers/staging/dgrp/dgrp_net_ops.c
> @@ -1607,7 +1607,7 @@ static int dgrp_send(struct nd_struct *nd, long tmax)
> if ((ch->ch_pun.un_flag & UN_LOW) != 0 ?
> (n <= TBUF_LOW) :
> (ch->ch_pun.un_flag & UN_TIME) != 0 ?
> - ((jiffies - ch->ch_waketime) >= 0) :
> + (jiffies >= ch->ch_waketime) :
What happens now when jiffies wraps?
Please use the proper jiffy comparison macros/functions instead of open
coding this and probably getting it wrong.
thanks,
greg k-h
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