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Date: Sun, 11 Oct 2015 17:21:06 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: netdev@...r.kernel.org
Cc: davem@...emloft.net, idosch@...lanox.com, eladr@...lanox.com,
sfeldma@...il.com, f.fainelli@...il.com, linux@...ck-us.net,
vivien.didelot@...oirfairelinux.com, andrew@...n.ch,
john.fastabend@...il.com, David.Laight@...LAB.COM,
stephen@...workplumber.org
Subject: [patch net-next 2/7] switchdev: allow caller to explicitly request attr_set as deferred
From: Jiri Pirko <jiri@...lanox.com>
Caller should know if he can call attr_set directly (when holding RTNL)
or if he has to defer the att_set processing for later.
This also allows drivers to sleep inside attr_set and report operation
status back to switchdev core. Switchdev core then warns if status is
not ok, instead of silent errors happening in drivers.
Signed-off-by: Jiri Pirko <jiri@...lanox.com>
---
include/net/switchdev.h | 1 +
net/bridge/br_stp.c | 3 +-
net/switchdev/switchdev.c | 107 ++++++++++++++++++++++++----------------------
3 files changed, 59 insertions(+), 52 deletions(-)
diff --git a/include/net/switchdev.h b/include/net/switchdev.h
index cc7f772..74e349a 100644
--- a/include/net/switchdev.h
+++ b/include/net/switchdev.h
@@ -16,6 +16,7 @@
#include <linux/list.h>
#define SWITCHDEV_F_NO_RECURSE BIT(0)
+#define SWITCHDEV_F_DEFER BIT(1)
struct switchdev_trans_item {
struct list_head list;
diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index 3a982c0..a90bf18 100644
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -41,13 +41,14 @@ void br_set_state(struct net_bridge_port *p, unsigned int state)
{
struct switchdev_attr attr = {
.id = SWITCHDEV_ATTR_ID_PORT_STP_STATE,
+ .flags = SWITCHDEV_F_DEFER,
.u.stp_state = state,
};
int err;
p->state = state;
err = switchdev_port_attr_set(p->dev, &attr);
- if (err && err != -EOPNOTSUPP)
+ if (err)
br_warn(p->br, "error setting offload STP state on port %u(%s)\n",
(unsigned int) p->port_no, p->dev->name);
}
diff --git a/net/switchdev/switchdev.c b/net/switchdev/switchdev.c
index 10306b6..8831dbd 100644
--- a/net/switchdev/switchdev.c
+++ b/net/switchdev/switchdev.c
@@ -166,6 +166,49 @@ static int __switchdev_port_attr_set(struct net_device *dev,
return err;
}
+static int switchdev_port_attr_set_now(struct net_device *dev,
+ struct switchdev_attr *attr)
+{
+ struct switchdev_trans trans;
+ int err;
+
+ switchdev_trans_init(&trans);
+
+ /* Phase I: prepare for attr set. Driver/device should fail
+ * here if there are going to be issues in the commit phase,
+ * such as lack of resources or support. The driver/device
+ * should reserve resources needed for the commit phase here,
+ * but should not commit the attr.
+ */
+
+ trans.ph_prepare = true;
+ err = __switchdev_port_attr_set(dev, attr, &trans);
+ if (err) {
+ /* Prepare phase failed: abort the transaction. Any
+ * resources reserved in the prepare phase are
+ * released.
+ */
+
+ if (err != -EOPNOTSUPP)
+ switchdev_trans_items_destroy(&trans);
+
+ return err;
+ }
+
+ /* Phase II: commit attr set. This cannot fail as a fault
+ * of driver/device. If it does, it's a bug in the driver/device
+ * because the driver said everythings was OK in phase I.
+ */
+
+ trans.ph_prepare = false;
+ err = __switchdev_port_attr_set(dev, attr, &trans);
+ WARN(err, "%s: Commit of attribute (id=%d) failed.\n",
+ dev->name, attr->id);
+ switchdev_trans_items_warn_destroy(dev, &trans);
+
+ return err;
+}
+
struct switchdev_attr_set_work {
struct work_struct work;
struct net_device *dev;
@@ -176,14 +219,17 @@ static void switchdev_port_attr_set_work(struct work_struct *work)
{
struct switchdev_attr_set_work *asw =
container_of(work, struct switchdev_attr_set_work, work);
+ bool rtnl_locked = rtnl_is_locked();
int err;
- rtnl_lock();
- err = switchdev_port_attr_set(asw->dev, &asw->attr);
+ if (!rtnl_locked)
+ rtnl_lock();
+ err = switchdev_port_attr_set_now(asw->dev, &asw->attr);
if (err && err != -EOPNOTSUPP)
netdev_err(asw->dev, "failed (err=%d) to set attribute (id=%d)\n",
err, asw->attr.id);
- rtnl_unlock();
+ if (!rtnl_locked)
+ rtnl_unlock();
dev_put(asw->dev);
kfree(work);
@@ -204,7 +250,7 @@ static int switchdev_port_attr_set_defer(struct net_device *dev,
asw->dev = dev;
memcpy(&asw->attr, attr, sizeof(asw->attr));
- schedule_work(&asw->work);
+ queue_work(switchdev_wq, &asw->work);
return 0;
}
@@ -218,57 +264,16 @@ static int switchdev_port_attr_set_defer(struct net_device *dev,
* Use a 2-phase prepare-commit transaction model to ensure
* system is not left in a partially updated state due to
* failure from driver/device.
+ *
+ * rtnl_lock must be held and must not be in atomic section,
+ * in case SWITCHDEV_F_DEFER flag is not set.
*/
int switchdev_port_attr_set(struct net_device *dev, struct switchdev_attr *attr)
{
- struct switchdev_trans trans;
- int err;
-
- if (!rtnl_is_locked()) {
- /* Running prepare-commit transaction across stacked
- * devices requires nothing moves, so if rtnl_lock is
- * not held, schedule a worker thread to hold rtnl_lock
- * while setting attr.
- */
-
+ if (attr->flags & SWITCHDEV_F_DEFER)
return switchdev_port_attr_set_defer(dev, attr);
- }
-
- switchdev_trans_init(&trans);
-
- /* Phase I: prepare for attr set. Driver/device should fail
- * here if there are going to be issues in the commit phase,
- * such as lack of resources or support. The driver/device
- * should reserve resources needed for the commit phase here,
- * but should not commit the attr.
- */
-
- trans.ph_prepare = true;
- err = __switchdev_port_attr_set(dev, attr, &trans);
- if (err) {
- /* Prepare phase failed: abort the transaction. Any
- * resources reserved in the prepare phase are
- * released.
- */
-
- if (err != -EOPNOTSUPP)
- switchdev_trans_items_destroy(&trans);
-
- return err;
- }
-
- /* Phase II: commit attr set. This cannot fail as a fault
- * of driver/device. If it does, it's a bug in the driver/device
- * because the driver said everythings was OK in phase I.
- */
-
- trans.ph_prepare = false;
- err = __switchdev_port_attr_set(dev, attr, &trans);
- WARN(err, "%s: Commit of attribute (id=%d) failed.\n",
- dev->name, attr->id);
- switchdev_trans_items_warn_destroy(dev, &trans);
-
- return err;
+ ASSERT_RTNL();
+ return switchdev_port_attr_set_now(dev, attr);
}
EXPORT_SYMBOL_GPL(switchdev_port_attr_set);
--
1.9.3
--
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