From: Julian Wiedmann <jwi@linux.ibm.com>
Subject: s390/qeth: fix request-side race during cmd IO timeout
Patch-mainline: v4.17-rc3
Git-commit: db71bbbd11a4d314f0fa3fbf3369b71cf33ce33c
References: FATE#326350, LTC#169511, bsc#1113509
Summary: qeth: performance improvements
Description: This adds recent functional and performance improvements for the
qeth network driver.
Primarily this brings Scatter-Gather support for HiperSockets,
reduced CPU consumption in the L3 IPv4 transmit path for OSA,
improved Promiscuous Mode performance due to IFF_UNICAST_FLT,
support for Scatter-Gather on z/VM virtual NICs, and
support for delayed GRO flushing.
For sanity & stability reasons, this effectively constitutes a
backport of the qeth device driver from 4.19 mainline.
Upstream-Description:
s390/qeth: fix request-side race during cmd IO timeout
Submitting a cmd IO request (usually on the WRITE device, but for IDX
also on the READ device) is currently done with ccw_device_start()
and a manual timeout in the caller.
On timeout, the caller cleans up the related resources (eg. IO buffer).
But 1) the IO might still be active and utilize those resources, and
2) when the IO completes, qeth_irq() will attempt to clean up the
same resources again.
Instead of introducing additional resource locking, switch to
ccw_device_start_timeout() to ensure IO termination after timeout, and
let the IRQ handler alone deal with cleaning up after a request.
This also removes a stray write->irq_pending reset from
clear_ipacmd_list(). The routine doesn't terminate any pending IO on
the WRITE device, so this should be handled properly via IO timeout
in the IRQ handler.
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/s390/net/qeth_core_main.c | 51 +++++++++++++++++++-------------------
drivers/s390/net/qeth_core_mpc.h | 12 ++++++++
drivers/s390/net/qeth_l2_main.c | 4 +-
3 files changed, 40 insertions(+), 27 deletions(-)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -714,7 +714,6 @@ void qeth_clear_ipacmd_list(struct qeth_
qeth_put_reply(reply);
}
spin_unlock_irqrestore(&card->lock, flags);
- atomic_set(&card->write.irq_pending, 0);
}
EXPORT_SYMBOL_GPL(qeth_clear_ipacmd_list);
@@ -1106,14 +1105,9 @@ static void qeth_irq(struct ccw_device *
{
int rc;
int cstat, dstat;
+ struct qeth_cmd_buffer *iob = NULL;
struct qeth_channel *channel;
struct qeth_card *card;
- struct qeth_cmd_buffer *iob;
-
- if (__qeth_check_irb_error(cdev, intparm, irb))
- return;
- cstat = irb->scsw.cmd.cstat;
- dstat = irb->scsw.cmd.dstat;
card = CARD_FROM_CDEV(cdev);
if (!card)
@@ -1131,6 +1125,19 @@ static void qeth_irq(struct ccw_device *
channel = &card->data;
QETH_CARD_TEXT(card, 5, "data");
}
+
+ if (qeth_intparm_is_iob(intparm))
+ iob = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
+
+ if (__qeth_check_irb_error(cdev, intparm, irb)) {
+ /* IO was terminated, free its resources. */
+ if (iob)
+ qeth_release_buffer(iob->channel, iob);
+ atomic_set(&channel->irq_pending, 0);
+ wake_up(&card->wait_q);
+ return;
+ }
+
atomic_set(&channel->irq_pending, 0);
if (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC))
@@ -1154,6 +1161,10 @@ static void qeth_irq(struct ccw_device *
/* we don't have to handle this further */
intparm = 0;
}
+
+ cstat = irb->scsw.cmd.cstat;
+ dstat = irb->scsw.cmd.dstat;
+
if ((dstat & DEV_STAT_UNIT_EXCEP) ||
(dstat & DEV_STAT_UNIT_CHECK) ||
(cstat)) {
@@ -1192,11 +1203,8 @@ static void qeth_irq(struct ccw_device *
channel->state == CH_STATE_UP)
__qeth_issue_next_read(card);
- if (intparm) {
- iob = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
- if (iob->callback)
- iob->callback(iob->channel, iob);
- }
+ if (iob && iob->callback)
+ iob->callback(iob->channel, iob);
out:
wake_up(&card->wait_q);
@@ -1867,8 +1875,8 @@ static int qeth_idx_activate_get_answer(
atomic_cmpxchg(&channel->irq_pending, 0, 1) == 0);
QETH_DBF_TEXT(SETUP, 6, "noirqpnd");
spin_lock_irqsave(get_ccwdev_lock(channel->ccwdev), flags);
- rc = ccw_device_start(channel->ccwdev,
- &channel->ccw, (addr_t) iob, 0, 0);
+ rc = ccw_device_start_timeout(channel->ccwdev, &channel->ccw,
+ (addr_t) iob, 0, 0, QETH_TIMEOUT);
spin_unlock_irqrestore(get_ccwdev_lock(channel->ccwdev), flags);
if (rc) {
@@ -1885,7 +1893,6 @@ static int qeth_idx_activate_get_answer(
if (channel->state != CH_STATE_UP) {
rc = -ETIME;
QETH_DBF_TEXT_(SETUP, 2, "3err%d", rc);
- qeth_clear_cmd_buffers(channel);
} else
rc = 0;
return rc;
@@ -1939,8 +1946,8 @@ static int qeth_idx_activate_channel(str
atomic_cmpxchg(&channel->irq_pending, 0, 1) == 0);
QETH_DBF_TEXT(SETUP, 6, "noirqpnd");
spin_lock_irqsave(get_ccwdev_lock(channel->ccwdev), flags);
- rc = ccw_device_start(channel->ccwdev,
- &channel->ccw, (addr_t) iob, 0, 0);
+ rc = ccw_device_start_timeout(channel->ccwdev, &channel->ccw,
+ (addr_t) iob, 0, 0, QETH_TIMEOUT);
spin_unlock_irqrestore(get_ccwdev_lock(channel->ccwdev), flags);
if (rc) {
@@ -1961,7 +1968,6 @@ static int qeth_idx_activate_channel(str
QETH_DBF_MESSAGE(2, "%s IDX activate timed out\n",
dev_name(&channel->ccwdev->dev));
QETH_DBF_TEXT_(SETUP, 2, "2err%d", -ETIME);
- qeth_clear_cmd_buffers(channel);
return -ETIME;
}
return qeth_idx_activate_get_answer(channel, idx_reply_cb);
@@ -2162,8 +2168,8 @@ int qeth_send_control_data(struct qeth_c
QETH_CARD_TEXT(card, 6, "noirqpnd");
spin_lock_irqsave(get_ccwdev_lock(card->write.ccwdev), flags);
- rc = ccw_device_start(card->write.ccwdev, &card->write.ccw,
- (addr_t) iob, 0, 0);
+ rc = ccw_device_start_timeout(CARD_WDEV(card), &card->write.ccw,
+ (addr_t) iob, 0, 0, event_timeout);
spin_unlock_irqrestore(get_ccwdev_lock(card->write.ccwdev), flags);
if (rc) {
QETH_DBF_MESSAGE(2, "%s qeth_send_control_data: "
@@ -2195,8 +2201,6 @@ int qeth_send_control_data(struct qeth_c
}
}
- if (reply->rc == -EIO)
- goto error;
rc = reply->rc;
qeth_put_reply(reply);
return rc;
@@ -2207,9 +2211,6 @@ time_err:
list_del_init(&reply->list);
spin_unlock_irqrestore(&reply->card->lock, flags);
atomic_inc(&reply->received);
-error:
- atomic_set(&card->write.irq_pending, 0);
- qeth_release_buffer(iob->channel, iob);
rc = reply->rc;
qeth_put_reply(reply);
return rc;
--- a/drivers/s390/net/qeth_core_mpc.h
+++ b/drivers/s390/net/qeth_core_mpc.h
@@ -34,6 +34,18 @@ extern unsigned char IPA_PDU_HEADER[];
#define QETH_HALT_CHANNEL_PARM -11
#define QETH_RCD_PARM -12
+static inline bool qeth_intparm_is_iob(unsigned long intparm)
+{
+ switch (intparm) {
+ case QETH_CLEAR_CHANNEL_PARM:
+ case QETH_HALT_CHANNEL_PARM:
+ case QETH_RCD_PARM:
+ case 0:
+ return false;
+ }
+ return true;
+}
+
/*****************************************************************************/
/* IP Assist related definitions */
/*****************************************************************************/
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -1351,8 +1351,8 @@ static int qeth_osn_send_control_data(st
qeth_prepare_control_data(card, len, iob);
QETH_CARD_TEXT(card, 6, "osnoirqp");
spin_lock_irqsave(get_ccwdev_lock(card->write.ccwdev), flags);
- rc = ccw_device_start(card->write.ccwdev, &card->write.ccw,
- (addr_t) iob, 0, 0);
+ rc = ccw_device_start_timeout(CARD_WDEV(card), &card->write.ccw,
+ (addr_t) iob, 0, 0, QETH_IPA_TIMEOUT);
spin_unlock_irqrestore(get_ccwdev_lock(card->write.ccwdev), flags);
if (rc) {
QETH_DBF_MESSAGE(2, "qeth_osn_send_control_data: "