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Commit 681dbd71 authored by Michael Chan's avatar Michael Chan Committed by David S. Miller
Browse files

cnic: Fix locking in start/stop calls. 



The slow path ulp_start and ulp_stop calls to the bnx2i driver
are sleepable calls and therefore should not be protected using
rcu_read_lock.  Fix it by using mutex and setting a bit during
these calls.  cnic_unregister_device() will now wait for the bit
to clear 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 c5a88950

drivers/net/cnic.c

+28 −16
Original line number Diff line number Diff line
@@ -466,6 +466,7 @@ EXPORT_SYMBOL(cnic_register_driver); 
static int cnic_unregister_device(struct cnic_dev *dev, int ulp_type)

{

	struct cnic_local *cp = dev->cnic_priv;

	int i = 0;



	if (ulp_type >= MAX_CNIC_ULP_TYPE) {

		printk(KERN_ERR PFX "cnic_unregister_device: Bad type %d\n",
@@ -486,6 +487,15 @@ static int cnic_unregister_device(struct cnic_dev *dev, int ulp_type) 


	synchronize_rcu();



	while (test_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[ulp_type]) &&

	       i < 20) {

		msleep(100);

		i++;

	}

	if (test_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[ulp_type]))

		printk(KERN_WARNING PFX "%s: Failed waiting for ULP up call"

					" to complete.\n", dev->netdev->name);



	return 0;

}

EXPORT_SYMBOL(cnic_unregister_driver);
@@ -1076,18 +1086,23 @@ static void cnic_ulp_stop(struct cnic_dev *dev) 
	if (cp->cnic_uinfo)

		cnic_send_nlmsg(cp, ISCSI_KEVENT_IF_DOWN, NULL);



	rcu_read_lock();

	for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) {

		struct cnic_ulp_ops *ulp_ops;



		ulp_ops = rcu_dereference(cp->ulp_ops[if_type]);

		if (!ulp_ops)

		mutex_lock(&cnic_lock);

		ulp_ops = cp->ulp_ops[if_type];

		if (!ulp_ops) {

			mutex_unlock(&cnic_lock);

			continue;

		}

		set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);

		mutex_unlock(&cnic_lock);



		if (test_and_clear_bit(ULP_F_START, &cp->ulp_flags[if_type]))

			ulp_ops->cnic_stop(cp->ulp_handle[if_type]);



		clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);

	}

	rcu_read_unlock();

}



static void cnic_ulp_start(struct cnic_dev *dev)
@@ -1095,18 +1110,23 @@ static void cnic_ulp_start(struct cnic_dev *dev) 
	struct cnic_local *cp = dev->cnic_priv;

	int if_type;



	rcu_read_lock();

	for (if_type = 0; if_type < MAX_CNIC_ULP_TYPE; if_type++) {

		struct cnic_ulp_ops *ulp_ops;



		ulp_ops = rcu_dereference(cp->ulp_ops[if_type]);

		if (!ulp_ops || !ulp_ops->cnic_start)

		mutex_lock(&cnic_lock);

		ulp_ops = cp->ulp_ops[if_type];

		if (!ulp_ops || !ulp_ops->cnic_start) {

			mutex_unlock(&cnic_lock);

			continue;

		}

		set_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);

		mutex_unlock(&cnic_lock);



		if (!test_and_set_bit(ULP_F_START, &cp->ulp_flags[if_type]))

			ulp_ops->cnic_start(cp->ulp_handle[if_type]);



		clear_bit(ULP_F_CALL_PENDING, &cp->ulp_flags[if_type]);

	}

	rcu_read_unlock();

}



static int cnic_ctl(void *data, struct cnic_ctl_info *info)
@@ -1116,22 +1136,18 @@ static int cnic_ctl(void *data, struct cnic_ctl_info *info) 
	switch (info->cmd) {

	case CNIC_CTL_STOP_CMD:

		cnic_hold(dev);

		mutex_lock(&cnic_lock);



		cnic_ulp_stop(dev);

		cnic_stop_hw(dev);



		mutex_unlock(&cnic_lock);

		cnic_put(dev);

		break;

	case CNIC_CTL_START_CMD:

		cnic_hold(dev);

		mutex_lock(&cnic_lock);



		if (!cnic_start_hw(dev))

			cnic_ulp_start(dev);



		mutex_unlock(&cnic_lock);

		cnic_put(dev);

		break;

	default:
@@ -2667,10 +2683,8 @@ static int cnic_netdev_event(struct notifier_block *this, unsigned long event, 
				cnic_put(dev);

				goto done;

			}

			mutex_lock(&cnic_lock);

			if (!cnic_start_hw(dev))

				cnic_ulp_start(dev);

			mutex_unlock(&cnic_lock);

		}



		rcu_read_lock();
@@ -2689,10 +2703,8 @@ static int cnic_netdev_event(struct notifier_block *this, unsigned long event, 
		rcu_read_unlock();



		if (event == NETDEV_GOING_DOWN) {

			mutex_lock(&cnic_lock);

			cnic_ulp_stop(dev);

			cnic_stop_hw(dev);

			mutex_unlock(&cnic_lock);

			cnic_unregister_netdev(dev);

		} else if (event == NETDEV_UNREGISTER) {

			write_lock(&cnic_dev_lock);

drivers/net/cnic.h

+1 −0
Original line number Diff line number Diff line
@@ -176,6 +176,7 @@ struct cnic_local { 
	unsigned long ulp_flags[MAX_CNIC_ULP_TYPE];

#define ULP_F_INIT	0

#define ULP_F_START	1

#define ULP_F_CALL_PENDING	2

	struct cnic_ulp_ops *ulp_ops[MAX_CNIC_ULP_TYPE];



	/* protected by ulp_lock */