netfront: fix netfront create_dev error path

[liuw_liuw.name]

Summary

The failure path for allocating rx grant refs should not try to free tx grant refs because tx grant refs were allocated after that.

Don't free tx grant refs twice.

[royger]

I have one comment, LMK what you think.

sys/dev/xen/netfront/netfront.c

1954

IMHO, I would rename this to error and add a KASSERT(err != 0, ("Error path with no error code specified"));

[liuw_liuw.name]

sys/dev/xen/netfront/netfront.c

1954

That's of course fine.

You can do that when you commit this patch if convenient. If you want me to update this patch or send a follow-up, please let me know.

[royger]

sys/dev/xen/netfront/netfront.c

1925–1926

Is this error case missing:

gnttab_free_grant_references(np->gref_tx_head);
gnttab_free_grant_references(np->gref_rx_head);

[liuw_liuw.name]

Also fix error path for xen_net_read_mac