Make 2 functions static to prevent build warnings:

arch/xtensa/platforms/iss/network.c:204:16: warning: no previous prototype for 'tuntap_protocol' [-Wmissing-prototypes]
  204 | unsigned short tuntap_protocol(struct sk_buff *skb)
arch/xtensa/platforms/iss/network.c:444:6: warning: no previous prototype for 'iss_net_user_timer_expire' [-Wmissing-prototypes]
  444 | void iss_net_user_timer_expire(struct timer_list *unused)

Fixes: 7282bee78798 ("xtensa: Architecture support for Tensilica Xtensa Part 8")
Fixes: d8479a21a98b ("xtensa: Convert timers to use timer_setup()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Message-Id: <20230920052139.10570-14-rdunlap@infradead.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

split_if_spec expects a NULL-pointer as an end marker for the argument
list, but tuntap_probe never supplied that terminating NULL. As a result
incorrectly formatted interface specification string may cause a crash
because of the random memory access. Fix that by adding NULL terminator
to the split_if_spec argument list.

Cc: stable@vger.kernel.org
Fixes: 7282bee78798 ("[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 8")
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

iss_net_configure explicitly frees etherdev in all error return paths
except one where register_netdevice fails. In that remaining error
return path the etherdev is freed by the iss_net_pdev_release callback
triggered by the platform_device_unregister call. Add a comment stating
that.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

The 'pdev' and 'netdev' need to be released in error cases of
iss_net_configure().

Change the return type of iss_net_configure() to void, because it's
not used.

Fixes: 7282bee78798 ("[PATCH] xtensa: Architecture support for Tensilica Xtensa Part 8")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Provide release() callback for the platform device embedded into struct
iss_net_private and registered in the iss_net_configure so that
platform_device_unregister could be called for it.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

There are two per-device lists in the ISS network driver: command line
parameters list and iss_net_private object list. The latter is only used
for duplicate checking in the function iss_net_setup where the former
should have been used.
Drop iss_net_private object list and associated code and use command
line parameters list in the iss_net_setup instead.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Instead of storing pointers to callback functions in the
struct iss_net_private::tp move them to struct struct iss_net_ops and
store a const pointer to it. Make static const tuntap_ops structure with
tuntap callbacks and initialize tp.net_ops with it in the tuntap_probe.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

Per-device locking in the ISS network driver is used to protect poll
timer and stats updates. Stat collection is not protected.
Remove per-device locking everywhere except the stats updates. Replace
ndo_get_stats callback with ndo_get_stats64 and use proper locking there
as well.
As a side effect this fixes possible deadlock between iss_net_close
and iss_net_timer.

Reported by: Duoming Zhou <duoming@zju.edu.cn>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

iss_net_set_mac is just a copy of eth_mac_addr with pointless locking.
Drop this function and replace it with eth_mac_addr.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

opened_list is used to poll all opened devices in the timer callback,
but there's individual timer that is associated with each device.
Drop opened_list and only poll the device that is associated with the
timer in the timer callback.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>