From: walter harms <wharms@bfs.de>
To: Colin King <colin.king@canonical.com>
Cc: "James E . J . Bottomley" <jejb@linux.vnet.ibm.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
Ching Huang <ching2048@areca.com.tw>,
linux-scsi@vger.kernel.org, kernel-janitors@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH][next] scsi: arcmsr: remove redundant check for secs < 0
Date: Fri, 15 Dec 2017 18:52:44 +0100 [thread overview]
Message-ID: <5A340BEC.6040704@bfs.de> (raw)
In-Reply-To: <20171209003414.17332-1-colin.king@canonical.com>
Am 09.12.2017 01:34, schrieb Colin King:
> From: Colin Ian King <colin.king@canonical.com>
>
> The check for secs being less than zero is redundant for two reasons.
> Firstly, secs is unsigned so the check is always going to be false.
> Secondly, if secs was signed the proceeding calculation of secs is
> never going to be negative. Hence we can remove this redundant check
> and day and secs re-adjustment.
>
> Detected by static analysis with smatch:
> arcmsr_set_iop_datetime() warn: unsigned 'secs' is never less than zero.
>
> Signed-off-by: Colin Ian King <colin.king@canonical.com>
> ---
> drivers/scsi/arcmsr/arcmsr_hba.c | 4 ----
> 1 file changed, 4 deletions(-)
>
> diff --git a/drivers/scsi/arcmsr/arcmsr_hba.c b/drivers/scsi/arcmsr/arcmsr_hba.c
> index 0707a60bf5c0..e4258b69f4be 100644
> --- a/drivers/scsi/arcmsr/arcmsr_hba.c
> +++ b/drivers/scsi/arcmsr/arcmsr_hba.c
> @@ -3679,10 +3679,6 @@ static void arcmsr_set_iop_datetime(struct timer_list *t)
> secs = (u32)(tv.tv_sec - (sys_tz.tz_minuteswest * 60));
> days = secs / 86400;
> secs = secs - 86400 * days;
mmh, what they want to do is:
secs = secs % 86400 ;
> - if (secs < 0) {
> - days = days - 1;
> - secs = secs + 86400;
> - }
> j = days / 146097;
> i = days - 146097 * j;
> a = i + 719468;
see above.
btw: are the numbers documented ?
re,
wh
prev parent reply other threads:[~2017-12-15 17:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-09 0:34 [PATCH][next] scsi: arcmsr: remove redundant check for secs < 0 Colin King
2017-12-11 2:41 ` 黃清隆
2017-12-12 2:37 ` Martin K. Petersen
2017-12-15 17:52 ` walter harms [this message]
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