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

[Shirley Ma]

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

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/