[net-next PATCH 1/2] macvtap: slient sparse warnings

[net-next PATCH 1/2] macvtap: slient sparse warnings

[Jason Wang]

This patch silents the following sparse warnings:

drivers/net/macvtap.c:98:9: warning: incorrect type in assignment (different
address spaces)
drivers/net/macvtap.c:98:9:    expected struct macvtap_queue *<noident>
drivers/net/macvtap.c:98:9:    got struct macvtap_queue [noderef]
<asn:4>*<noident>
drivers/net/macvtap.c:120:9: warning: incorrect type in assignment (different
address spaces)
drivers/net/macvtap.c:120:9:    expected struct macvtap_queue *<noident>
drivers/net/macvtap.c:120:9:    got struct macvtap_queue [noderef]
<asn:4>*<noident>
drivers/net/macvtap.c:151:22: error: incompatible types in comparison expression
(different address spaces)
drivers/net/macvtap.c:233:23: error: incompatible types in comparison expression
(different address spaces)
drivers/net/macvtap.c:243:23: error: incompatible types in comparison expression
(different address spaces)
drivers/net/macvtap.c:247:15: error: incompatible types in comparison expression
(different address spaces)
  CC [M]  drivers/net/macvtap.o
drivers/net/macvlan.c:232:24: error: incompatible types in comparison expression
(different address spaces)

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/macvtap.c      |    2 +-
 include/linux/if_macvlan.h |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 992151c..acf55ba 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -429,7 +429,7 @@ static int macvtap_open(struct inode *inode, struct file *file)
 	if (!q)
 		goto out;
 
-	q->sock.wq = &q->wq;
+	rcu_assign_pointer(q->sock.wq, &q->wq);
 	init_waitqueue_head(&q->wq.wait);
 	q->sock.type = SOCK_RAW;
 	q->sock.state = SS_CONNECTED;
diff --git a/include/linux/if_macvlan.h b/include/linux/if_macvlan.h
index 1912133..f49a9f6 100644
--- a/include/linux/if_macvlan.h
+++ b/include/linux/if_macvlan.h
@@ -70,7 +70,7 @@ struct macvlan_dev {
 	int (*receive)(struct sk_buff *skb);
 	int (*forward)(struct net_device *dev, struct sk_buff *skb);
 	/* This array tracks active taps. */
-	struct macvtap_queue	*taps[MAX_MACVTAP_QUEUES];
+	struct macvtap_queue	__rcu *taps[MAX_MACVTAP_QUEUES];
 	/* This list tracks all taps (both enabled and disabled) */
 	struct list_head	queue_list;
 	int			numvtaps;
-- 
1.7.1

[net-next PATCH 2/2] macvtap: fix uninitialized return value macvtap_ioctl_set_queue()

[Jason Wang]

Return -EINVAL on illegal flag instead of uninitialized value. This fixes the
kbuild test warning.

Signed-off-by: Jason Wang <jasowang@redhat.com>
---
 drivers/net/macvtap.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index acf55ba..9f03ce3 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -969,6 +969,8 @@ static int macvtap_ioctl_set_queue(struct file *file, unsigned int flags)
 		ret = macvtap_enable_queue(vlan->dev, file, q);
 	else if (flags & IFF_DETACH_QUEUE)
 		ret = macvtap_disable_queue(q);
+	else
+		ret = -EINVAL;
 
 	macvtap_put_vlan(vlan);
 	return ret;
-- 
1.7.1

Re: [net-next PATCH 1/2] macvtap: slient sparse warnings

[Eric Dumazet]

On Thu, 2013-06-13 at 12:21 +0800, Jason Wang wrote:
> This patch silents the following sparse warnings:
> 
> dr
> Signed-off-by: Jason Wang <jasowang@redhat.com>
> ---
>  drivers/net/macvtap.c      |    2 +-
>  include/linux/if_macvlan.h |    2 +-
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 992151c..acf55ba 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -429,7 +429,7 @@ static int macvtap_open(struct inode *inode, struct file *file)
>  	if (!q)
>  		goto out;
>  
> -	q->sock.wq = &q->wq;
> +	rcu_assign_pointer(q->sock.wq, &q->wq);

Since nobody but you [1] can access this object at that time, you could
rather use
	RCU_INIT_POINTER(q->sock.wq, &q->wq);

rcu_assign_pointer() is also a documentation point (memory barrier)

By using RCU_INIT_POINTER() you clearly show that you know you need no
memory barrier.

>  	init_waitqueue_head(&q->wq.wait);

[1] :
or else, this init_waitqueue_head() should be done _before_ the
rcu_asign_pointer()

>  	q->sock.type = SOCK_RAW;
>  	q->sock.state = SS_CONNECTED;

Re: [net-next PATCH 1/2] macvtap: slient sparse warnings

[Jason Wang]

On 06/13/2013 01:48 PM, Eric Dumazet wrote:
> On Thu, 2013-06-13 at 12:21 +0800, Jason Wang wrote:
>> This patch silents the following sparse warnings:
>>
>> dr
>> Signed-off-by: Jason Wang <jasowang@redhat.com>
>> ---
>>  drivers/net/macvtap.c      |    2 +-
>>  include/linux/if_macvlan.h |    2 +-
>>  2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
>> index 992151c..acf55ba 100644
>> --- a/drivers/net/macvtap.c
>> +++ b/drivers/net/macvtap.c
>> @@ -429,7 +429,7 @@ static int macvtap_open(struct inode *inode, struct file *file)
>>  	if (!q)
>>  		goto out;
>>  
>> -	q->sock.wq = &q->wq;
>> +	rcu_assign_pointer(q->sock.wq, &q->wq);
> Since nobody but you [1] can access this object at that time, you could
> rather use
> 	RCU_INIT_POINTER(q->sock.wq, &q->wq);
>
> rcu_assign_pointer() is also a documentation point (memory barrier)
>
> By using RCU_INIT_POINTER() you clearly show that you know you need no
> memory barrier.
>

True.
>>  	init_waitqueue_head(&q->wq.wait);
> [1] :
> or else, this init_waitqueue_head() should be done _before_ the
> rcu_asign_pointer()

Thanks, I will send v2 by using RCU_INIT_POINTER().
>
>>  	q->sock.type = SOCK_RAW;
>>  	q->sock.state = SS_CONNECTED;
>
> --
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