Re: [PATCH v4] drivers: s390: net: ctcm: migrate variables to handle y2038 problem
From: Ursula Braun
Date: Tue Nov 04 2014 - 04:41:37 EST
thx, Aya. This time you forgot this part:
--- a/drivers/s390/net/ctcm_sysfs.c
+++ b/drivers/s390/net/ctcm_sysfs.c
@@ -100,8 +100,8 @@ static void ctcm_print_statistics(struct
priv->channel[WRITE]->prof.doios_multi);
p += sprintf(p, " Netto bytes written: %ld\n",
priv->channel[WRITE]->prof.txlen);
- p += sprintf(p, " Max. TX IO-time: %ld\n",
- priv->channel[WRITE]->prof.tx_time);
+ p += sprintf(p, " Max. TX IO-time: %u\n",
+ jiffies_to_usecs(priv->channel[WRITE]->prof.tx_time));
printk(KERN_INFO "Statistics for %s:\n%s",
priv->channel[CTCM_WRITE]->netdev->name,
sbuf);
Regards, Ursula Braun
On Mon, 2014-11-03 at 21:33 +0200, Aya Mahfouz wrote:
> This patch is concerned with migrating the time variables for the s390
> network driver. The changes handle the y2038 problem where timespec will
> overflow in the year 2038. timespec was replaced by unsigned long and
> all time variables get their values from the jiffies global variable.
> This was done for the sake of speed and efficiency.
>
> ch->prof.tx_time will now hold the difference between two jiffies'
> values instead of the difference between two xtime values
> represented in microseconds.
>
> Signed-off-by: Aya Mahfouz <mahfouz.saif.elyazal@xxxxxxxxx>
> ---
> v1: Arnd has advised me to provide you with options for time
> calculation. The first option: "accuracy" is used in this
> patch. The second option: "speed" can be done through
> jiffies.
>
> v2: Moved on to the speed option. Let me know if I explicitly
> need to include the jiffies header. The module compiles with
> no problems on my side.
>
> v3: Handled the error pointed out by Ursula. The current version
> does not handle overflows. There are two solutions for this.
> The first is to use jiffies_64 since s/390 is a 64-bit
> architecture after all. The second is to use wrapper functions
> like time_before and time_after. Two files were added too.
> They are: ctcm_main.c and netiucv.c. This patch could be sent
> as a patchset in its final version for convenience.
>
> v4: removed #include <linux/jiffies.h> per Ursula's feedback.
> Changed duration to hold the difference between jiffies
> instead of difference between microsecond values per Arnd's
> suggestion.
>
> drivers/s390/net/ctcm_fsms.c | 18 +++++++-----------
> drivers/s390/net/ctcm_main.c | 4 ++--
> drivers/s390/net/ctcm_main.h | 2 +-
> drivers/s390/net/netiucv.c | 6 +++---
> 4 files changed, 13 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/s390/net/ctcm_fsms.c b/drivers/s390/net/ctcm_fsms.c
> index fb92524..49143c3 100644
> --- a/drivers/s390/net/ctcm_fsms.c
> +++ b/drivers/s390/net/ctcm_fsms.c
> @@ -251,13 +251,11 @@ static void chx_txdone(fsm_instance *fi, int event, void *arg)
> int first = 1;
> int i;
> unsigned long duration;
> - struct timespec done_stamp = current_kernel_time(); /* xtime */
> + unsigned long done_stamp jiffies;
>
> CTCM_PR_DEBUG("%s(%s): %s\n", __func__, ch->id, dev->name);
>
> - duration =
> - (done_stamp.tv_sec - ch->prof.send_stamp.tv_sec) * 1000000 +
> - (done_stamp.tv_nsec - ch->prof.send_stamp.tv_nsec) / 1000;
> + duration = done_stamp -ch->prof.send_stamp;
> if (duration > ch->prof.tx_time)
> ch->prof.tx_time = duration;
>
> @@ -307,7 +305,7 @@ static void chx_txdone(fsm_instance *fi, int event, void *arg)
> spin_unlock(&ch->collect_lock);
> ch->ccw[1].count = ch->trans_skb->len;
> fsm_addtimer(&ch->timer, CTCM_TIME_5_SEC, CTC_EVENT_TIMER, ch);
> - ch->prof.send_stamp = current_kernel_time(); /* xtime */
> + ch->prof.send_stamp = jiffies;
> rc = ccw_device_start(ch->cdev, &ch->ccw[0],
> (unsigned long)ch, 0xff, 0);
> ch->prof.doios_multi++;
> @@ -1229,14 +1227,12 @@ static void ctcmpc_chx_txdone(fsm_instance *fi, int event, void *arg)
> int rc;
> struct th_header *header;
> struct pdu *p_header;
> - struct timespec done_stamp = current_kernel_time(); /* xtime */
> + unsigned long done_stamp = jiffies;
>
> CTCM_PR_DEBUG("Enter %s: %s cp:%i\n",
> __func__, dev->name, smp_processor_id());
>
> - duration =
> - (done_stamp.tv_sec - ch->prof.send_stamp.tv_sec) * 1000000 +
> - (done_stamp.tv_nsec - ch->prof.send_stamp.tv_nsec) / 1000;
> + duration = done_stamp -ch->prof.send_stamp;
> if (duration > ch->prof.tx_time)
> ch->prof.tx_time = duration;
>
> @@ -1361,7 +1357,7 @@ static void ctcmpc_chx_txdone(fsm_instance *fi, int event, void *arg)
>
> ch->ccw[1].count = ch->trans_skb->len;
> fsm_addtimer(&ch->timer, CTCM_TIME_5_SEC, CTC_EVENT_TIMER, ch);
> - ch->prof.send_stamp = current_kernel_time(); /* xtime */
> + ch->prof.send_stamp = jiffies;
> if (do_debug_ccw)
> ctcmpc_dumpit((char *)&ch->ccw[0], sizeof(struct ccw1) * 3);
> rc = ccw_device_start(ch->cdev, &ch->ccw[0],
> @@ -1827,7 +1823,7 @@ static void ctcmpc_chx_send_sweep(fsm_instance *fsm, int event, void *arg)
> fsm_newstate(wch->fsm, CTC_STATE_TX);
>
> spin_lock_irqsave(get_ccwdev_lock(wch->cdev), saveflags);
> - wch->prof.send_stamp = current_kernel_time(); /* xtime */
> + wch->prof.send_stamp = jiffies;
> rc = ccw_device_start(wch->cdev, &wch->ccw[3],
> (unsigned long) wch, 0xff, 0);
> spin_unlock_irqrestore(get_ccwdev_lock(wch->cdev), saveflags);
> diff --git a/drivers/s390/net/ctcm_main.c b/drivers/s390/net/ctcm_main.c
> index e056dd4..05c37d6 100644
> --- a/drivers/s390/net/ctcm_main.c
> +++ b/drivers/s390/net/ctcm_main.c
> @@ -567,7 +567,7 @@ static int ctcm_transmit_skb(struct channel *ch, struct sk_buff *skb)
> fsm_newstate(ch->fsm, CTC_STATE_TX);
> fsm_addtimer(&ch->timer, CTCM_TIME_5_SEC, CTC_EVENT_TIMER, ch);
> spin_lock_irqsave(get_ccwdev_lock(ch->cdev), saveflags);
> - ch->prof.send_stamp = current_kernel_time(); /* xtime */
> + ch->prof.send_stamp = jiffies;
> rc = ccw_device_start(ch->cdev, &ch->ccw[ccw_idx],
> (unsigned long)ch, 0xff, 0);
> spin_unlock_irqrestore(get_ccwdev_lock(ch->cdev), saveflags);
> @@ -831,7 +831,7 @@ static int ctcmpc_transmit_skb(struct channel *ch, struct sk_buff *skb)
> sizeof(struct ccw1) * 3);
>
> spin_lock_irqsave(get_ccwdev_lock(ch->cdev), saveflags);
> - ch->prof.send_stamp = current_kernel_time(); /* xtime */
> + ch->prof.send_stamp = jiffies;
> rc = ccw_device_start(ch->cdev, &ch->ccw[ccw_idx],
> (unsigned long)ch, 0xff, 0);
> spin_unlock_irqrestore(get_ccwdev_lock(ch->cdev), saveflags);
> diff --git a/drivers/s390/net/ctcm_main.h b/drivers/s390/net/ctcm_main.h
> index 477c933..6f4417c 100644
> --- a/drivers/s390/net/ctcm_main.h
> +++ b/drivers/s390/net/ctcm_main.h
> @@ -121,7 +121,7 @@ struct ctcm_profile {
> unsigned long doios_multi;
> unsigned long txlen;
> unsigned long tx_time;
> - struct timespec send_stamp;
> + unsigned long send_stamp;
> };
>
> /*
> diff --git a/drivers/s390/net/netiucv.c b/drivers/s390/net/netiucv.c
> index 0a87809..7e91f54 100644
> --- a/drivers/s390/net/netiucv.c
> +++ b/drivers/s390/net/netiucv.c
> @@ -178,7 +178,7 @@ struct connection_profile {
> unsigned long doios_multi;
> unsigned long txlen;
> unsigned long tx_time;
> - struct timespec send_stamp;
> + unsigned long send_stamp;
> unsigned long tx_pending;
> unsigned long tx_max_pending;
> };
> @@ -786,7 +786,7 @@ static void conn_action_txdone(fsm_instance *fi, int event, void *arg)
>
> header.next = 0;
> memcpy(skb_put(conn->tx_buff, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
> - conn->prof.send_stamp = current_kernel_time();
> + conn->prof.send_stamp = jiffies;
> txmsg.class = 0;
> txmsg.tag = 0;
> rc = iucv_message_send(conn->path, &txmsg, 0, 0,
> @@ -1220,7 +1220,7 @@ static int netiucv_transmit_skb(struct iucv_connection *conn,
> memcpy(skb_put(nskb, NETIUCV_HDRLEN), &header, NETIUCV_HDRLEN);
>
> fsm_newstate(conn->fsm, CONN_STATE_TX);
> - conn->prof.send_stamp = current_kernel_time();
> + conn->prof.send_stamp = jiffies;
>
> msg.tag = 1;
> msg.class = 0;
--
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