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Commit 078efae0 authored by Anish Bhatt's avatar Anish Bhatt Committed by James Bottomley
Browse files

[SCSI] cxgb4i: avoid holding mutex in interrupt context 



cxgbi_inet6addr_handler() can be called in interrupt context, so use rcu
protected list while finding netdev.  This is observed as a scheduling in
atomic oops when running over ipv6.

Fixes: fc8d0590 ("libcxgbi: Add ipv6 api to driver")
Fixes: 759a0cc5 ("cxgb4i: Add ipv6 code to driver, call into libcxgbi ipv6 api")

Signed-off-by: default avatarAnish Bhatt <anish@chelsio.com>
Signed-off-by: default avatarKaren Xie <kxie@chelsio.com>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 7d1311b9

drivers/scsi/cxgbi/cxgb4i/cxgb4i.c

+1 −1
Original line number Diff line number Diff line
@@ -1647,7 +1647,7 @@ static int cxgbi_inet6addr_handler(struct notifier_block *this, 
	if (event_dev->priv_flags & IFF_802_1Q_VLAN)

		event_dev = vlan_dev_real_dev(event_dev);



	cdev = cxgbi_device_find_by_netdev(event_dev, NULL);

	cdev = cxgbi_device_find_by_netdev_rcu(event_dev, NULL);



	if (!cdev)

		return ret;

drivers/scsi/cxgbi/libcxgbi.c

+51 −6
Original line number Diff line number Diff line
@@ -57,6 +57,9 @@ MODULE_PARM_DESC(dbg_level, "libiscsi debug level (default=0)"); 
static LIST_HEAD(cdev_list);

static DEFINE_MUTEX(cdev_mutex);



static LIST_HEAD(cdev_rcu_list);

static DEFINE_SPINLOCK(cdev_rcu_lock);



int cxgbi_device_portmap_create(struct cxgbi_device *cdev, unsigned int base,

				unsigned int max_conn)

{
@@ -142,6 +145,10 @@ struct cxgbi_device *cxgbi_device_register(unsigned int extra, 
	list_add_tail(&cdev->list_head, &cdev_list);

	mutex_unlock(&cdev_mutex);



	spin_lock(&cdev_rcu_lock);

	list_add_tail_rcu(&cdev->rcu_node, &cdev_rcu_list);

	spin_unlock(&cdev_rcu_lock);



	log_debug(1 << CXGBI_DBG_DEV,

		"cdev 0x%p, p# %u.\n", cdev, nports);

	return cdev;
@@ -153,9 +160,16 @@ void cxgbi_device_unregister(struct cxgbi_device *cdev) 
	log_debug(1 << CXGBI_DBG_DEV,

		"cdev 0x%p, p# %u,%s.\n",

		cdev, cdev->nports, cdev->nports ? cdev->ports[0]->name : "");



	mutex_lock(&cdev_mutex);

	list_del(&cdev->list_head);

	mutex_unlock(&cdev_mutex);



	spin_lock(&cdev_rcu_lock);

	list_del_rcu(&cdev->rcu_node);

	spin_unlock(&cdev_rcu_lock);

	synchronize_rcu();



	cxgbi_device_destroy(cdev);

}

EXPORT_SYMBOL_GPL(cxgbi_device_unregister);
@@ -167,12 +181,9 @@ void cxgbi_device_unregister_all(unsigned int flag) 
	mutex_lock(&cdev_mutex);

	list_for_each_entry_safe(cdev, tmp, &cdev_list, list_head) {

		if ((cdev->flags & flag) == flag) {

			log_debug(1 << CXGBI_DBG_DEV,

				"cdev 0x%p, p# %u,%s.\n",

				cdev, cdev->nports, cdev->nports ?

				 cdev->ports[0]->name : "");

			list_del(&cdev->list_head);

			cxgbi_device_destroy(cdev);

			mutex_unlock(&cdev_mutex);

			cxgbi_device_unregister(cdev);

			mutex_lock(&cdev_mutex);

		}

	}

	mutex_unlock(&cdev_mutex);
@@ -191,6 +202,7 @@ struct cxgbi_device *cxgbi_device_find_by_lldev(void *lldev) 
		}

	}

	mutex_unlock(&cdev_mutex);



	log_debug(1 << CXGBI_DBG_DEV,

		"lldev 0x%p, NO match found.\n", lldev);

	return NULL;
@@ -230,6 +242,39 @@ struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *ndev, 
}

EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev);



struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *ndev,

						     int *port)

{

	struct net_device *vdev = NULL;

	struct cxgbi_device *cdev;

	int i;



	if (ndev->priv_flags & IFF_802_1Q_VLAN) {

		vdev = ndev;

		ndev = vlan_dev_real_dev(ndev);

		pr_info("vlan dev %s -> %s.\n", vdev->name, ndev->name);

	}



	rcu_read_lock();

	list_for_each_entry_rcu(cdev, &cdev_rcu_list, rcu_node) {

		for (i = 0; i < cdev->nports; i++) {

			if (ndev == cdev->ports[i]) {

				cdev->hbas[i]->vdev = vdev;

				rcu_read_unlock();

				if (port)

					*port = i;

				return cdev;

			}

		}

	}

	rcu_read_unlock();



	log_debug(1 << CXGBI_DBG_DEV,

		  "ndev 0x%p, %s, NO match found.\n", ndev, ndev->name);

	return NULL;

}

EXPORT_SYMBOL_GPL(cxgbi_device_find_by_netdev_rcu);



static struct cxgbi_device *cxgbi_device_find_by_mac(struct net_device *ndev,

						     int *port)

{

drivers/scsi/cxgbi/libcxgbi.h

+3 −0
Original line number Diff line number Diff line
@@ -527,6 +527,7 @@ struct cxgbi_ports_map { 
#define CXGBI_FLAG_IPV4_SET		0x10

struct cxgbi_device {

	struct list_head list_head;

	struct list_head rcu_node;

	unsigned int flags;

	struct net_device **ports;

	void *lldev;
@@ -709,6 +710,8 @@ void cxgbi_device_unregister(struct cxgbi_device *); 
void cxgbi_device_unregister_all(unsigned int flag);

struct cxgbi_device *cxgbi_device_find_by_lldev(void *);

struct cxgbi_device *cxgbi_device_find_by_netdev(struct net_device *, int *);

struct cxgbi_device *cxgbi_device_find_by_netdev_rcu(struct net_device *,

						     int *);

int cxgbi_hbas_add(struct cxgbi_device *, u64, unsigned int,

			struct scsi_host_template *,

			struct scsi_transport_template *);