linux/net/xdp
Maxim Mikityanskiy 96dee90a9d xsk: Add rcu_read_lock around the XSK wakeup
[ Upstream commit 0687068208 ]

The XSK wakeup callback in drivers makes some sanity checks before
triggering NAPI. However, some configuration changes may occur during
this function that affect the result of those checks. For example, the
interface can go down, and all the resources will be destroyed after the
checks in the wakeup function, but before it attempts to use these
resources. Wrap this callback in rcu_read_lock to allow driver to
synchronize_rcu before actually destroying the resources.

xsk_wakeup is a new function that encapsulates calling ndo_xsk_wakeup
wrapped into the RCU lock. After this commit, xsk_poll starts using
xsk_wakeup and checks xs->zc instead of ndo_xsk_wakeup != NULL to decide
ndo_xsk_wakeup should be called. It also fixes a bug introduced with the
need_wakeup feature: a non-zero-copy socket may be used with a driver
supporting zero-copy, and in this case ndo_xsk_wakeup should not be
called, so the xs->zc check is the correct one.

Fixes: 77cd0d7b3f ("xsk: add support for need_wakeup flag in AF_XDP rings")
Signed-off-by: Maxim Mikityanskiy <maximmi@mellanox.com>
Signed-off-by: Björn Töpel <bjorn.topel@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20191217162023.16011-2-maximmi@mellanox.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-12 12:21:41 +01:00
..
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
xdp_umem.c xsk: Fix registration of Rx-only sockets 2019-10-23 20:22:11 -07:00
xdp_umem.h xdp: fix hang while unregistering device bound to xdp socket 2019-07-03 15:10:55 +02:00
xsk.c xsk: Add rcu_read_lock around the XSK wakeup 2020-01-12 12:21:41 +01:00
xsk.h xsk: add support for need_wakeup flag in AF_XDP rings 2019-08-17 23:07:32 +02:00
xsk_diag.c xsk: lock the control mutex in sock_diag interface 2019-09-05 14:11:52 +02:00
xsk_queue.c net: xsk: add a simple buffer reuse queue 2018-09-25 13:13:15 -07:00
xsk_queue.h xsk: add support to allow unaligned chunk placement 2019-08-31 01:08:26 +02:00