[PATCH 1/2] macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()

[PATCH 1/2] macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()

[Zhi Yong Wu]

From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

By checking related codes, it is impossible that ret > len or total_len,
so we should remove some useless coeds in both above functions.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
 drivers/net/macvtap.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 4c6f84c..7f4ccdd 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -871,7 +871,6 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
 	}
 
 	ret = macvtap_do_read(q, iv, len, file->f_flags & O_NONBLOCK);
-	ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
 out:
 	return ret;
 }
@@ -1104,10 +1103,6 @@ static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
 		return -EINVAL;
 	ret = macvtap_do_read(q, m->msg_iov, total_len,
 			  flags & MSG_DONTWAIT);
-	if (ret > total_len) {
-		m->msg_flags |= MSG_TRUNC;
-		ret = flags & MSG_TRUNC ? ret : total_len;
-	}
 	return ret;
 }
 
-- 
1.7.6.5

[PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[Zhi Yong Wu]

From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

By checking related codes, it is impossible that ret > len or total_len,
so we should remove some useless codes in both above functions.

Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
---
 drivers/net/tun.c |    5 -----
 1 files changed, 0 insertions(+), 5 deletions(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index f9c935a..d61719c 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1354,7 +1354,6 @@ static ssize_t tun_chr_aio_read(struct kiocb *iocb, const struct iovec *iv,
 
 	ret = tun_do_read(tun, tfile, iv, len,
 			  file->f_flags & O_NONBLOCK);
-	ret = min_t(ssize_t, ret, len);
 out:
 	tun_put(tun);
 	return ret;
@@ -1453,10 +1452,6 @@ static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 	}
 	ret = tun_do_read(tun, tfile, m->msg_iov, total_len,
 			  flags & MSG_DONTWAIT);
-	if (ret > total_len) {
-		m->msg_flags |= MSG_TRUNC;
-		ret = flags & MSG_TRUNC ? ret : total_len;
-	}
 out:
 	tun_put(tun);
 	return ret;
-- 
1.7.6.5

Re: [PATCH 1/2] macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()

[Vlad Yasevich]

On 12/06/2013 03:54 PM, Zhi Yong Wu wrote:
> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> 
> By checking related codes, it is impossible that ret > len or total_len,
> so we should remove some useless coeds in both above functions.

Looks like commit 6680ec68eff47d36f67b4351bc9836fd6cba9532
Author: Jason Wang <jasowang@redhat.com>
Date:   Thu Jul 25 13:00:33 2013 +0800

    tuntap: hardware vlan tx support

Introduced a change in tun_put_user() where we can
never return a length longer then len or total_len.
This has an effect that is now impossible to signal
truncated status.  It seems like a potential loss
of functionality and it might make sense to restore it.

-vlad
> 
> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> ---
>  drivers/net/macvtap.c |    5 -----
>  1 files changed, 0 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
> index 4c6f84c..7f4ccdd 100644
> --- a/drivers/net/macvtap.c
> +++ b/drivers/net/macvtap.c
> @@ -871,7 +871,6 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
>  	}
>  
>  	ret = macvtap_do_read(q, iv, len, file->f_flags & O_NONBLOCK);
> -	ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
>  out:
>  	return ret;
>  }
> @@ -1104,10 +1103,6 @@ static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
>  		return -EINVAL;
>  	ret = macvtap_do_read(q, m->msg_iov, total_len,
>  			  flags & MSG_DONTWAIT);
> -	if (ret > total_len) {
> -		m->msg_flags |= MSG_TRUNC;
> -		ret = flags & MSG_TRUNC ? ret : total_len;
> -	}
>  	return ret;
>  }
>  
> 

Re: [PATCH 1/2] macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()

[Jason Wang]

On 12/07/2013 10:38 AM, Vlad Yasevich wrote:
> On 12/06/2013 03:54 PM, Zhi Yong Wu wrote:
>> > From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>> > 
>> > By checking related codes, it is impossible that ret > len or total_len,
>> > so we should remove some useless coeds in both above functions.
> Looks like commit 6680ec68eff47d36f67b4351bc9836fd6cba9532
> Author: Jason Wang <jasowang@redhat.com>
> Date:   Thu Jul 25 13:00:33 2013 +0800
>
>     tuntap: hardware vlan tx support
>
> Introduced a change in tun_put_user() where we can
> never return a length longer then len or total_len.
> This has an effect that is now impossible to signal
> truncated status.  It seems like a potential loss
> of functionality and it might make sense to restore it.
>
> -vlad

True, will send a patch. For macvtap, we'd better also correct current
behaviour to be same with tun.

Thanks

Re: [PATCH 1/2] macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()

[David Miller]

From: Zhi Yong Wu <zwu.kernel@gmail.com>
Date: Sat,  7 Dec 2013 04:54:59 +0800

> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> 
> By checking related codes, it is impossible that ret > len or total_len,
> so we should remove some useless coeds in both above functions.
> 
> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

Applied.

Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[David Miller]

From: Zhi Yong Wu <zwu.kernel@gmail.com>
Date: Sat,  7 Dec 2013 04:55:00 +0800

> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> 
> By checking related codes, it is impossible that ret > len or total_len,
> so we should remove some useless codes in both above functions.
> 
> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>

Applied.

Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[Vlad Yasevich]

On 12/09/2013 08:36 PM, David Miller wrote:
> From: Zhi Yong Wu <zwu.kernel@gmail.com>
> Date: Sat,  7 Dec 2013 04:55:00 +0800
> 
>> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>
>> By checking related codes, it is impossible that ret > len or total_len,
>> so we should remove some useless codes in both above functions.
>>
>> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> 
> Applied.

Wait a sec.  We want to be able to return a value bigger then len
to trigger a MSG_TRUNC.  Jason has patches for to fix this.  If you
apply this, we'll have to re-introduce this code back in.

Same goes for patch 1/2.

-vlad

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Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[David Miller]

From: Vlad Yasevich <vyasevich@gmail.com>
Date: Tue, 10 Dec 2013 12:18:09 -0500

> On 12/09/2013 08:36 PM, David Miller wrote:
>> From: Zhi Yong Wu <zwu.kernel@gmail.com>
>> Date: Sat,  7 Dec 2013 04:55:00 +0800
>> 
>>> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>>
>>> By checking related codes, it is impossible that ret > len or total_len,
>>> so we should remove some useless codes in both above functions.
>>>
>>> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>> 
>> Applied.
> 
> Wait a sec.  We want to be able to return a value bigger then len
> to trigger a MSG_TRUNC.  Jason has patches for to fix this.  If you
> apply this, we'll have to re-introduce this code back in.
> 
> Same goes for patch 1/2.

That's fine, right now the code makes no sense as the condition can
never be triggered so there is no harm removing the illogical code
meanwhile.

Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[Zhi Yong Wu]

Only one reminder, since David has committed the two patches, you
maybe need to take their impact on your patches into account.

On Wed, Dec 11, 2013 at 3:00 AM, David Miller <davem@davemloft.net> wrote:
> From: Vlad Yasevich <vyasevich@gmail.com>
> Date: Tue, 10 Dec 2013 12:18:09 -0500
>
>> On 12/09/2013 08:36 PM, David Miller wrote:
>>> From: Zhi Yong Wu <zwu.kernel@gmail.com>
>>> Date: Sat,  7 Dec 2013 04:55:00 +0800
>>>
>>>> From: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>>>
>>>> By checking related codes, it is impossible that ret > len or total_len,
>>>> so we should remove some useless codes in both above functions.
>>>>
>>>> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>>
>>> Applied.
>>
>> Wait a sec.  We want to be able to return a value bigger then len
>> to trigger a MSG_TRUNC.  Jason has patches for to fix this.  If you
>> apply this, we'll have to re-introduce this code back in.
>>
>> Same goes for patch 1/2.
>
> That's fine, right now the code makes no sense as the condition can
> never be triggered so there is no harm removing the illogical code
> meanwhile.



-- 
Regards,

Zhi Yong Wu

Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[David Miller]

From: Zhi Yong Wu <zwu.kernel@gmail.com>
Date: Wed, 11 Dec 2013 11:14:04 +0800

> Only one reminder, since David has committed the two patches, you
> maybe need to take their impact on your patches into account.

I reverted these changes from net-next.

Re: [PATCH 2/2] tun: remove useless codes in tun_chr_aio_read() and tun_recvmsg()

[Zhi Yong Wu]

On Wed, Dec 11, 2013 at 11:19 AM, David Miller <davem@davemloft.net> wrote:
> From: Zhi Yong Wu <zwu.kernel@gmail.com>
> Date: Wed, 11 Dec 2013 11:14:04 +0800
>
>> Only one reminder, since David has committed the two patches, you
>> maybe need to take their impact on your patches into account.
>
> I reverted these changes from net-next.
So rapid:), thanks for your reminder.



-- 
Regards,

Zhi Yong Wu