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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, "David S. Miller" <davem@davemloft.net>,
        "Julian Wiedmann" <jwi@linux.vnet.ibm.com>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.851760249@decadent.org.uk>
Subject: [PATCH 3.16 223/410] s390/qeth: fix SETIP command handling
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

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

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

commit 1c5b2216fbb973a9410e0b06389740b5c1289171 upstream.

send_control_data() applies some special handling to SETIP v4 IPA
commands. But current code parses *all* command types for the SETIP
command code. Limit the command code check to IPA commands.

Fixes: 5b54e16f1a54 ("qeth: do not spin for SETIP ip assist command")
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/s390/net/qeth_core.h      |  5 +++++
 drivers/s390/net/qeth_core_main.c | 14 ++++++++------
 2 files changed, 13 insertions(+), 6 deletions(-)

--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -593,6 +593,11 @@ struct qeth_cmd_buffer {
 	void (*callback) (struct qeth_channel *, struct qeth_cmd_buffer *);
 };
 
+static inline struct qeth_ipa_cmd *__ipa_cmd(struct qeth_cmd_buffer *iob)
+{
+	return (struct qeth_ipa_cmd *)(iob->data + IPA_PDU_HEADER_SIZE);
+}
+
 /**
  * definition of a qeth channel, used for read and write
  */
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -2025,7 +2025,7 @@ int qeth_send_control_data(struct qeth_c
 	unsigned long flags;
 	struct qeth_reply *reply = NULL;
 	unsigned long timeout, event_timeout;
-	struct qeth_ipa_cmd *cmd;
+	struct qeth_ipa_cmd *cmd = NULL;
 
 	QETH_CARD_TEXT(card, 2, "sendctl");
 
@@ -2052,10 +2052,13 @@ int qeth_send_control_data(struct qeth_c
 	while (atomic_cmpxchg(&card->write.irq_pending, 0, 1)) ;
 	qeth_prepare_control_data(card, len, iob);
 
-	if (IS_IPA(iob->data))
+	if (IS_IPA(iob->data)) {
+		cmd = __ipa_cmd(iob);
 		event_timeout = QETH_IPA_TIMEOUT;
-	else
+	} else {
 		event_timeout = QETH_TIMEOUT;
+	}
+
 	timeout = jiffies + event_timeout;
 
 	QETH_CARD_TEXT(card, 6, "noirqpnd");
@@ -2080,9 +2083,8 @@ int qeth_send_control_data(struct qeth_c
 
 	/* we have only one long running ipassist, since we can ensure
 	   process context of this command we can sleep */
-	cmd = (struct qeth_ipa_cmd *)(iob->data+IPA_PDU_HEADER_SIZE);
-	if ((cmd->hdr.command == IPA_CMD_SETIP) &&
-	    (cmd->hdr.prot_version == QETH_PROT_IPV4)) {
+	if (cmd && cmd->hdr.command == IPA_CMD_SETIP &&
+	    cmd->hdr.prot_version == QETH_PROT_IPV4) {
 		if (!wait_event_timeout(reply->wait_q,
 		    atomic_read(&reply->received), event_timeout))
 			goto time_err;