linux-kernel - [char-misc-next 07/11] mei: fix flow control for single buffer clients

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1427408887-27979-7-git-send-email-tomas.winkler@intel.com>
Date:	Fri, 27 Mar 2015 00:28:03 +0200
From:	Tomas Winkler <tomas.winkler@...el.com>
To:	gregkh@...uxfoundation.org
Cc:	arnd@...db.de, linux-kernel@...r.kernel.org,
	Alexander Usyskin <alexander.usyskin@...el.com>,
	Tomas Winkler <tomas.winkler@...el.com>
Subject: [char-misc-next 07/11] mei: fix flow control for single buffer clients

From: Alexander Usyskin <alexander.usyskin@...el.com>

For ME clients that use single receiving buffer
the driver tracks credentials on mei_me_clients structure
for all connections. The driver needs to book keep the shared
resource correctly and track the connections, particularly
the credit has to be cleaned when there is no active connection
to a particular me client. This solves issue when subsequent
connection will not get an ill impression that it can write.

We add active connection counter the particular ME client and
when the counter reach zero, we clear the credits.

Signed-off-by: Alexander Usyskin <alexander.usyskin@...el.com>
Signed-off-by: Tomas Winkler <tomas.winkler@...el.com>
---
 drivers/misc/mei/client.c  | 29 +++++++++++++++++++++++------
 drivers/misc/mei/mei_dev.h |  4 ++++
 2 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c
index aa1d35a51e9f..98335b435b75 100644
--- a/drivers/misc/mei/client.c
+++ b/drivers/misc/mei/client.c
@@ -749,10 +749,31 @@ void mei_cl_set_disconnected(struct mei_cl *cl)
 	cl->mei_flow_ctrl_creds = 0;
 	cl->timer_count = 0;
 
+	if (!cl->me_cl)
+		return;
+
+	if (!WARN_ON(cl->me_cl->connect_count == 0))
+		cl->me_cl->connect_count--;
+
+	if (cl->me_cl->connect_count == 0)
+		cl->me_cl->mei_flow_ctrl_creds = 0;
+
 	mei_me_cl_put(cl->me_cl);
 	cl->me_cl = NULL;
 }
 
+static int mei_cl_set_connecting(struct mei_cl *cl, struct mei_me_client *me_cl)
+{
+	cl->me_cl = mei_me_cl_get(me_cl);
+	if (!cl->me_cl)
+		return -ENOENT;
+
+	cl->state = MEI_FILE_CONNECTING;
+	cl->me_cl->connect_count++;
+
+	return 0;
+}
+
 /*
  * mei_cl_send_disconnect - send disconnect request
  *
@@ -1009,13 +1030,9 @@ int mei_cl_connect(struct mei_cl *cl, struct mei_me_client *me_cl,
 	if (rets)
 		goto out;
 
-	cl->me_cl = mei_me_cl_get(me_cl);
-	if (!cl->me_cl) {
-		rets = -ENODEV;
+	rets = mei_cl_set_connecting(cl, me_cl);
+	if (rets)
 		goto out;
-	}
-
-	cl->state = MEI_FILE_CONNECTING;
 	list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
 
 	/* run hbuf acquire last so we don't have to undo */
diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h
index 711e4fa8b708..f17979c680a9 100644
--- a/drivers/misc/mei/mei_dev.h
+++ b/drivers/misc/mei/mei_dev.h
@@ -177,6 +177,8 @@ struct mei_fw_status {
  * @props: client properties
  * @client_id: me client id
  * @mei_flow_ctrl_creds: flow control credits
+ * @connect_count: number connections to this client
+ * @reserved: reserved
  */
 struct mei_me_client {
 	struct list_head list;
@@ -184,6 +186,8 @@ struct mei_me_client {
 	struct mei_client_properties props;
 	u8 client_id;
 	u8 mei_flow_ctrl_creds;
+	u8 connect_count;
+	u8 reserved;
 };
 
 
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/