[4.2.y-ckt stable] Patch "mei: amthif: discard not read messages" has been added to the 4.2.y-ckt tree

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    mei: amthif: discard not read messages

to the linux-4.2.y-queue branch of the 4.2.y-ckt extended stable tree 
which can be found at:

    https://git.launchpad.net/~canonical-kernel/linux/+git/linux-stable-ckt/log/?h=linux-4.2.y-queue

This patch is scheduled to be released in version 4.2.8-ckt12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 4.2.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

---8<------------------------------------------------------------

>From 66f4bf737569fdcfac8996d8e0c75589eccf7f59 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin at intel.com>
Date: Sun, 17 Apr 2016 12:16:04 -0400
Subject: mei: amthif: discard not read messages

commit 9d04ee11db7bf0d848266cbfd7db336097a0e239 upstream.

When a message is received and amthif client is not in reading state
the message is ignored and left dangling in the queue. This may happen
after one of the amthif host connections is closed w/o completing the
reading. Another client will pick up a wrong message on next read
attempt which will lead to link reset.
To prevent this the driver has to properly discard the message when
amthif client is not in reading state.

Signed-off-by: Alexander Usyskin <alexander.usyskin at intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler at intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/misc/mei/amthif.c    | 4 +++-
 drivers/misc/mei/interrupt.c | 1 -
 drivers/misc/mei/mei_dev.h   | 2 ++
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/mei/amthif.c b/drivers/misc/mei/amthif.c
index 1e42781..eee1a96 100644
--- a/drivers/misc/mei/amthif.c
+++ b/drivers/misc/mei/amthif.c
@@ -417,8 +417,10 @@ int mei_amthif_irq_read_msg(struct mei_cl *cl,

 	dev = cl->dev;

-	if (dev->iamthif_state != MEI_IAMTHIF_READING)
+	if (dev->iamthif_state != MEI_IAMTHIF_READING) {
+		mei_irq_discard_msg(dev, mei_hdr);
 		return 0;
+	}

 	ret = mei_cl_irq_read_msg(cl, mei_hdr, cmpl_list);
 	if (ret)
diff --git a/drivers/misc/mei/interrupt.c b/drivers/misc/mei/interrupt.c
index 15dbac8..c879823 100644
--- a/drivers/misc/mei/interrupt.c
+++ b/drivers/misc/mei/interrupt.c
@@ -75,7 +75,6 @@ static inline int mei_cl_hbm_equal(struct mei_cl *cl,
  * @dev: mei device
  * @hdr: message header
  */
-static inline
 void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr)
 {
 	/*
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index bc65fb4..aa040f9 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -768,6 +768,8 @@ bool mei_hbuf_acquire(struct mei_device *dev);

 bool mei_write_is_idle(struct mei_device *dev);

+void mei_irq_discard_msg(struct mei_device *dev, struct mei_msg_hdr *hdr);
+
 #if IS_ENABLED(CONFIG_DEBUG_FS)
 int mei_dbgfs_register(struct mei_device *dev, const char *name);
 void mei_dbgfs_deregister(struct mei_device *dev);
--
2.7.4