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RDMA/ocrdma: Don't sleep in atomic notifier handler

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Events sent to ocrdma_inet6addr_event() are sent from an atomic context,
therefore we can't try to lock a mutex within the notifier callback.

We could just switch the mutex to a spinlock since all it does it
protect a list, but I've gone ahead and switched the list to use RCU
instead.  I couldn't fully test it since I don't have IB hardware, so
if it doesn't fully work for some reason let me know and I'll switch
it back to using a spinlock.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>

[ Fixed locking in ocrdma_add().  - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>
This commit is contained in:
Sasha Levin 2012-04-28 07:40:01 +02:00 committed by Roland Dreier
parent c592c42331
commit 3e4d60a82e
2 changed files with 23 additions and 16 deletions
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1
drivers/infiniband/hw/ocrdma/ocrdma.h
View file

@ -168,6 +168,7 @@ struct ocrdma_dev {
struct be_dev_info nic_info;
struct list_head entry;
struct rcu_head rcu;
int id;
};

38
drivers/infiniband/hw/ocrdma/ocrdma_main.c
View file

@ -47,7 +47,7 @@ MODULE_AUTHOR("Emulex Corporation");
MODULE_LICENSE("GPL");
static LIST_HEAD(ocrdma_dev_list);
static DEFINE_MUTEX(ocrdma_devlist_lock);
static DEFINE_SPINLOCK(ocrdma_devlist_lock);
static DEFINE_IDR(ocrdma_dev_id);
static union ib_gid ocrdma_zero_sgid;
@ -221,14 +221,14 @@ static int ocrdma_inet6addr_event(struct notifier_block *notifier,
is_vlan = true;
vid = vlan_dev_vlan_id(event_netdev);
}
mutex_lock(&ocrdma_devlist_lock);
list_for_each_entry(dev, &ocrdma_dev_list, entry) {
rcu_read_lock();
list_for_each_entry_rcu(dev, &ocrdma_dev_list, entry) {
if (dev->nic_info.netdev == netdev) {
found = true;
break;
}
}
mutex_unlock(&ocrdma_devlist_lock);
rcu_read_unlock();
if (!found)
return NOTIFY_DONE;
@ -431,9 +431,9 @@ static struct ocrdma_dev *ocrdma_add(struct be_dev_info *dev_info)
if (status)
goto alloc_err;
mutex_lock(&ocrdma_devlist_lock);
list_add_tail(&dev->entry, &ocrdma_dev_list);
mutex_unlock(&ocrdma_devlist_lock);
spin_lock(&ocrdma_devlist_lock);
list_add_tail_rcu(&dev->entry, &ocrdma_dev_list);
spin_unlock(&ocrdma_devlist_lock);
return dev;
alloc_err:
@ -448,16 +448,9 @@ static struct ocrdma_dev *ocrdma_add(struct be_dev_info *dev_info)
return NULL;
}
static void ocrdma_remove(struct ocrdma_dev *dev)
static void ocrdma_remove_free(struct rcu_head *rcu)
{
/* first unregister with stack to stop all the active traffic
* of the registered clients.
*/
ib_unregister_device(&dev->ibdev);
mutex_lock(&ocrdma_devlist_lock);
list_del(&dev->entry);
mutex_unlock(&ocrdma_devlist_lock);
struct ocrdma_dev *dev = container_of(rcu, struct ocrdma_dev, rcu);
ocrdma_free_resources(dev);
ocrdma_cleanup_hw(dev);
@ -467,6 +460,19 @@ static void ocrdma_remove(struct ocrdma_dev *dev)
ib_dealloc_device(&dev->ibdev);
}
static void ocrdma_remove(struct ocrdma_dev *dev)
{
/* first unregister with stack to stop all the active traffic
* of the registered clients.
*/
ib_unregister_device(&dev->ibdev);
spin_lock(&ocrdma_devlist_lock);
list_del_rcu(&dev->entry);
spin_unlock(&ocrdma_devlist_lock);
call_rcu(&dev->rcu, ocrdma_remove_free);
}
static int ocrdma_open(struct ocrdma_dev *dev)
{
struct ib_event port_event;