cnic: Fix locking in init/exit calls.
The slow path ulp_init and ulp_exit calls to the bnx2i driver
are sleepable calls and therefore should not be protected using
rcu_read_lock. Fix it by using mutex and refcount during these
calls. cnic_unregister_driver() will now wait for the refcount
to go to zero before completing the call.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Reviewed-by: Benjamin Li <benli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/cnic.c b/drivers/net/cnic.c
index 4ff618a..74c3429 100644
--- a/drivers/net/cnic.c
+++ b/drivers/net/cnic.c
@@ -138,6 +138,16 @@
return NULL;
}
+static inline void ulp_get(struct cnic_ulp_ops *ulp_ops)
+{
+ atomic_inc(&ulp_ops->ref_count);
+}
+
+static inline void ulp_put(struct cnic_ulp_ops *ulp_ops)
+{
+ atomic_dec(&ulp_ops->ref_count);
+}
+
static void cnic_ctx_wr(struct cnic_dev *dev, u32 cid_addr, u32 off, u32 val)
{
struct cnic_local *cp = dev->cnic_priv;
@@ -358,6 +368,7 @@
}
read_unlock(&cnic_dev_lock);
+ atomic_set(&ulp_ops->ref_count, 0);
rcu_assign_pointer(cnic_ulp_tbl[ulp_type], ulp_ops);
mutex_unlock(&cnic_lock);
@@ -379,6 +390,8 @@
int cnic_unregister_driver(int ulp_type)
{
struct cnic_dev *dev;
+ struct cnic_ulp_ops *ulp_ops;
+ int i = 0;
if (ulp_type >= MAX_CNIC_ULP_TYPE) {
printk(KERN_ERR PFX "cnic_unregister_driver: Bad type %d\n",
@@ -386,7 +399,8 @@
return -EINVAL;
}
mutex_lock(&cnic_lock);
- if (!cnic_ulp_tbl[ulp_type]) {
+ ulp_ops = cnic_ulp_tbl[ulp_type];
+ if (!ulp_ops) {
printk(KERN_ERR PFX "cnic_unregister_driver: Type %d has not "
"been registered\n", ulp_type);
goto out_unlock;
@@ -411,6 +425,14 @@
mutex_unlock(&cnic_lock);
synchronize_rcu();
+ while ((atomic_read(&ulp_ops->ref_count) != 0) && (i < 20)) {
+ msleep(100);
+ i++;
+ }
+
+ if (atomic_read(&ulp_ops->ref_count) != 0)
+ printk(KERN_WARNING PFX "%s: Failed waiting for ref count to go"
+ " to zero.\n", dev->netdev->name);
return 0;
out_unlock:
@@ -1161,19 +1183,23 @@
int i;
struct cnic_local *cp = dev->cnic_priv;
- rcu_read_lock();
for (i = 0; i < MAX_CNIC_ULP_TYPE_EXT; i++) {
struct cnic_ulp_ops *ulp_ops;
- ulp_ops = rcu_dereference(cnic_ulp_tbl[i]);
- if (!ulp_ops || !ulp_ops->cnic_init)
+ mutex_lock(&cnic_lock);
+ ulp_ops = cnic_ulp_tbl[i];
+ if (!ulp_ops || !ulp_ops->cnic_init) {
+ mutex_unlock(&cnic_lock);
continue;
+ }
+ ulp_get(ulp_ops);
+ mutex_unlock(&cnic_lock);
if (!test_and_set_bit(ULP_F_INIT, &cp->ulp_flags[i]))
ulp_ops->cnic_init(dev);
+ ulp_put(ulp_ops);
}
- rcu_read_unlock();
}
static void cnic_ulp_exit(struct cnic_dev *dev)
@@ -1181,19 +1207,23 @@
int i;
struct cnic_local *cp = dev->cnic_priv;
- rcu_read_lock();
for (i = 0; i < MAX_CNIC_ULP_TYPE_EXT; i++) {
struct cnic_ulp_ops *ulp_ops;
- ulp_ops = rcu_dereference(cnic_ulp_tbl[i]);
- if (!ulp_ops || !ulp_ops->cnic_exit)
+ mutex_lock(&cnic_lock);
+ ulp_ops = cnic_ulp_tbl[i];
+ if (!ulp_ops || !ulp_ops->cnic_exit) {
+ mutex_unlock(&cnic_lock);
continue;
+ }
+ ulp_get(ulp_ops);
+ mutex_unlock(&cnic_lock);
if (test_and_clear_bit(ULP_F_INIT, &cp->ulp_flags[i]))
ulp_ops->cnic_exit(dev);
+ ulp_put(ulp_ops);
}
- rcu_read_unlock();
}
static int cnic_cm_offload_pg(struct cnic_sock *csk)