Re: [V2 PATCH 4/9] macvtap: zerocopy: set SKBTX_DEV_ZEROCOPY onlywhen skb is built successfully

[Jason Wang]

On 05/16/2012 01:44 AM, Shirley Ma wrote:
> On Wed, 2012-05-02 at 11:42 +0800, Jason Wang wrote:
> > Current the SKBTX_DEV_ZEROCOPY is set unconditionally after
> > zerocopy_sg_from_iovec(), this would lead NULL pointer when macvtap
> > fails to build zerocopy skb because destructor_arg was not
> > initialized. Solve this by set this flag after the skb were built
> > successfully.
> I thought this flag was needed for zerocopy skb free even in err case.
> I've checked it back again, it's OK to move the flag after the skb
> successfully built. Or we can fix it by modify skb free with
> destructor_arg NULL check as below:
> ...
> skb_release_data() {
> ...
>                  if (skb_shinfo(skb)->tx_flags&  SKBTX_DEV_ZEROCOPY) {
>                          struct ubuf_info *uarg;
>
>                          uarg = skb_shinfo(skb)->destructor_arg;
>                          if (uarg&&  uarg->callback)
>                                  uarg->callback(uarg);
>                  }
>
> ...
> }
> Thanks
> Shirley
Yes, both are ok. Since the code were merged, let's just use current method.
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