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Commit 7fc1ece4 authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
Browse files

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: default avatarMichael Chan <mchan@broadcom.com>
Reviewed-by: default avatarBenjamin Li <benli@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 681dbd71

drivers/net/cnic.c

+39 −9
Original line number Diff line number Diff line
@@ -138,6 +138,16 @@ static struct cnic_dev *cnic_from_netdev(struct net_device *netdev) 
	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 @@ int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops) 
	}

	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_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops) 
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 @@ int cnic_unregister_driver(int ulp_type) 
		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 @@ int cnic_unregister_driver(int ulp_type) 


	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 @@ static void cnic_ulp_init(struct cnic_dev *dev) 
	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 @@ static void cnic_ulp_exit(struct cnic_dev *dev) 
	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)

drivers/net/cnic_if.h

+1 −0
Original line number Diff line number Diff line
@@ -290,6 +290,7 @@ struct cnic_ulp_ops { 
	void (*iscsi_nl_send_msg)(struct cnic_dev *dev, u32 msg_type,

				  char *data, u16 data_size);

	struct module *owner;

	atomic_t ref_count;

};



extern int cnic_register_driver(int ulp_type, struct cnic_ulp_ops *ulp_ops);