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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Julian Wiedmann <jwi@linux.vnet.ibm.com>,
	"David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.16 48/81] s390/qeth: avoid control IO completion stalls
Date: Fri, 27 Apr 2018 15:58:50 +0200	[thread overview]
Message-ID: <20180427135745.960188443@linuxfoundation.org> (raw)
In-Reply-To: <20180427135743.216853156@linuxfoundation.org>

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Julian Wiedmann <jwi@linux.vnet.ibm.com>


[ Upstream commit 901e3f49facbd31b2b3d1786637b4a35e1022e9b ]

For control IO, qeth currently tracks the index of the buffer that it
expects to complete the next IO on each qeth_channel. If the channel
presents an IRQ while this buffer has not yet completed, no completion
processing for _any_ completed buffer takes place.
So if the 'next buffer' is skipped for any sort of reason* (eg. when it
is released due to error conditions, before the IO is started), the
buffer obviously won't switch to PROCESSED until it is eventually
allocated for a _different_ IO and completes.
Until this happens, all completion processing on that channel stalls
and pending requests possibly time out.

As a fix, remove the whole 'next buffer' logic and simply process any
IO buffer right when it completes. A channel will never have more than
one IO pending, so there's no risk of processing out-of-sequence.

*Note: currently just one location in the code really handles this problem,
       by advancing the 'next' index manually.

Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/s390/net/qeth_core.h      |    2 --
 drivers/s390/net/qeth_core_main.c |   22 +++++-----------------
 2 files changed, 5 insertions(+), 19 deletions(-)

--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -565,7 +565,6 @@ enum qeth_ip_types {
 enum qeth_cmd_buffer_state {
 	BUF_STATE_FREE,
 	BUF_STATE_LOCKED,
-	BUF_STATE_PROCESSED,
 };
 
 enum qeth_cq {
@@ -609,7 +608,6 @@ struct qeth_channel {
 	struct qeth_cmd_buffer iob[QETH_CMD_BUFFER_NO];
 	atomic_t irq_pending;
 	int io_buf_no;
-	int buf_no;
 };
 
 /**
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -821,7 +821,6 @@ void qeth_clear_cmd_buffers(struct qeth_
 
 	for (cnt = 0; cnt < QETH_CMD_BUFFER_NO; cnt++)
 		qeth_release_buffer(channel, &channel->iob[cnt]);
-	channel->buf_no = 0;
 	channel->io_buf_no = 0;
 }
 EXPORT_SYMBOL_GPL(qeth_clear_cmd_buffers);
@@ -927,7 +926,6 @@ static int qeth_setup_channel(struct qet
 			kfree(channel->iob[cnt].data);
 		return -ENOMEM;
 	}
-	channel->buf_no = 0;
 	channel->io_buf_no = 0;
 	atomic_set(&channel->irq_pending, 0);
 	spin_lock_init(&channel->iob_lock);
@@ -1103,11 +1101,9 @@ static void qeth_irq(struct ccw_device *
 {
 	int rc;
 	int cstat, dstat;
-	struct qeth_cmd_buffer *buffer;
 	struct qeth_channel *channel;
 	struct qeth_card *card;
 	struct qeth_cmd_buffer *iob;
-	__u8 index;
 
 	if (__qeth_check_irb_error(cdev, intparm, irb))
 		return;
@@ -1185,25 +1181,18 @@ static void qeth_irq(struct ccw_device *
 		channel->state = CH_STATE_RCD_DONE;
 		goto out;
 	}
-	if (intparm) {
-		buffer = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
-		buffer->state = BUF_STATE_PROCESSED;
-	}
 	if (channel == &card->data)
 		return;
 	if (channel == &card->read &&
 	    channel->state == CH_STATE_UP)
 		__qeth_issue_next_read(card);
 
-	iob = channel->iob;
-	index = channel->buf_no;
-	while (iob[index].state == BUF_STATE_PROCESSED) {
-		if (iob[index].callback != NULL)
-			iob[index].callback(channel, iob + index);
-
-		index = (index + 1) % QETH_CMD_BUFFER_NO;
+	if (intparm) {
+		iob = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
+		if (iob->callback)
+			iob->callback(iob->channel, iob);
 	}
-	channel->buf_no = index;
+
 out:
 	wake_up(&card->wait_q);
 	return;
@@ -2217,7 +2206,6 @@ time_err:
 error:
 	atomic_set(&card->write.irq_pending, 0);
 	qeth_release_buffer(iob->channel, iob);
-	card->write.buf_no = (card->write.buf_no + 1) % QETH_CMD_BUFFER_NO;
 	rc = reply->rc;
 	qeth_put_reply(reply);
 	return rc;

  parent reply	other threads:[~2018-04-27 13:58 UTC|newest]

Thread overview: 88+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-27 13:58 [PATCH 4.16 00/81] 4.16.6-stable review Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 01/81] Revert "pinctrl: intel: Initialize GPIO properly when used through irqchip" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 02/81] drm: bridge: dw-hdmi: Fix overflow workaround for Amlogic Meson GX SoCs Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 03/81] i40e: Fix attach VF to VM issue Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 04/81] tpm: cmd_ready command can be issued only after granting locality Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 05/81] tpm: tpm-interface: fix tpm_transmit/_cmd kdoc Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 06/81] tpm: add retry logic Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 07/81] Revert "ath10k: send (re)assoc peer command when NSS changed" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 08/81] bonding: do not set slave_dev npinfo before slave_enable_netpoll in bond_enslave Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 09/81] docs: ip-sysctl.txt: fix name of some ipv6 variables Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 10/81] ipv6: add RTA_TABLE and RTA_PREFSRC to rtm_ipv6_policy Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 11/81] ipv6: sr: fix NULL pointer dereference in seg6_do_srh_encap()- v4 pkts Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 12/81] KEYS: DNS: limit the length of option strings Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 13/81] l2tp: check sockaddr length in pppol2tp_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 14/81] llc: delete timers synchronously in llc_sk_free() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 15/81] net: af_packet: fix race in PACKET_{R|T}X_RING Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 16/81] net: fix deadlock while clearing neighbor proxy table Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 17/81] net: mvpp2: Fix DMA address mask size Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 18/81] net: qmi_wwan: add Wistron Neweb D19Q1 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 19/81] net/smc: fix shutdown in state SMC_LISTEN Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 20/81] net: stmmac: Disable ACS Feature for GMAC >= 4 Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 21/81] packet: fix bitfield update race Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 22/81] pppoe: check sockaddr length in pppoe_connect() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 23/81] Revert "macsec: missing dev_put() on error in macsec_newlink()" Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 24/81] sctp: do not check port in sctp_inet6_cmp_addr Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 25/81] strparser: Do not call mod_delayed_work with a timeout of LONG_MAX Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 26/81] strparser: Fix incorrect strp->need_bytes value Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 27/81] tcp: clear tp->packets_out when purging write queue Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 28/81] tcp: dont read out-of-bounds opsize Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 29/81] tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 30/81] team: avoid adding twice the same option to the event list Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 31/81] team: fix netconsole setup over team Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 32/81] tipc: add policy for TIPC_NLA_NET_ADDR Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 33/81] vlan: Fix reading memory beyond skb->tail in skb_vlan_tagged_multi Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 34/81] vmxnet3: fix incorrect dereference when rxvlan is disabled Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 35/81] amd-xgbe: Add pre/post auto-negotiation phy hooks Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 36/81] amd-xgbe: Improve KR auto-negotiation and training Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 37/81] amd-xgbe: Only use the SFP supported transceiver signals Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 38/81] net: sched: ife: signal not finding metaid Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 39/81] net: sched: ife: handle malformed tlv length Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 40/81] net: sched: ife: check on metadata length Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 41/81] l2tp: hold reference on tunnels in netlink dumps Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 42/81] l2tp: hold reference on tunnels printed in pppol2tp proc file Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 43/81] l2tp: hold reference on tunnels printed in l2tp/tunnels debugfs file Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 44/81] l2tp: fix {pppol2tp, l2tp_dfs}_seq_stop() in case of seq_file overflow Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 45/81] llc: hold llc_sap before release_sock() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 46/81] llc: fix NULL pointer deref for SOCK_ZAPPED Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 47/81] s390/qeth: fix error handling in adapter command callbacks Greg Kroah-Hartman
2018-04-27 13:58 ` Greg Kroah-Hartman [this message]
2018-04-27 13:58 ` [PATCH 4.16 49/81] s390/qeth: handle failure on workqueue creation Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 50/81] net: ethernet: ti: cpsw: fix tx vlan priority mapping Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 51/81] net: validate attribute sizes in neigh_dump_table() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 52/81] bnxt_en: Fix memory fault in bnxt_ethtool_init() Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 53/81] virtio-net: add missing virtqueue kick when flushing packets Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 54/81] VSOCK: make af_vsock.ko removable again Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 55/81] net: aquantia: Regression on reset with 1.x firmware Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 56/81] tun: fix vlan packet truncation Greg Kroah-Hartman
2018-04-27 13:58 ` [PATCH 4.16 57/81] net: aquantia: oops when shutdown on already stopped device Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 58/81] virtio_net: split out ctrl buffer Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 59/81] virtio_net: fix adding vids on big-endian Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 60/81] Revert "mm/hmm: fix header file if/else/endif maze" Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 61/81] commoncap: Handle memory allocation failure Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 62/81] scsi: mptsas: Disable WRITE SAME Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 63/81] cdrom: information leak in cdrom_ioctl_media_changed() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 64/81] fsnotify: Fix fsnotify_mark_connector race Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 65/81] m68k/mac: Dont remap SWIM MMIO region Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 66/81] block/swim: Check drive type Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 67/81] block/swim: Dont log an error message for an invalid ioctl Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 68/81] block/swim: Remove extra put_disk() call from error path Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 69/81] block/swim: Rename macros to avoid inconsistent inverted logic Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 70/81] block/swim: Select appropriate drive on device open Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 71/81] block/swim: Fix array bounds check Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 72/81] block/swim: Fix IO error at end of medium Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 73/81] tracing: Fix missing tab for hwlat_detector print format Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 74/81] hwmon: (k10temp) Add temperature offset for Ryzen 2700X Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 75/81] hwmon: (k10temp) Add support for AMD Ryzen w/ Vega graphics Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 76/81] s390/cio: update chpid descriptor after resource accessibility event Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 77/81] s390/dasd: fix IO error for newly defined devices Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 78/81] s390/uprobes: implement arch_uretprobe_is_alive() Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 79/81] s390/cpum_cf: rename IBM z13/z14 counter names Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 80/81] kprobes: Fix random address output of blacklist file Greg Kroah-Hartman
2018-04-27 13:59 ` [PATCH 4.16 81/81] ACPI / video: Only default only_lcd to true on Win8-ready _desktops_ Greg Kroah-Hartman
2018-04-27 18:15 ` [PATCH 4.16 00/81] 4.16.6-stable review Shuah Khan
2018-04-27 20:41 ` Dan Rue
2018-04-28  5:50   ` Greg Kroah-Hartman
2018-04-27 20:44 ` kernelci.org bot
2018-04-28 14:32 ` Guenter Roeck
2018-04-28 15:52   ` Greg Kroah-Hartman

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