The Linux 4.4.119 kernel (and perhaps others) from kernel.org
backports some dst_cache code that breaks the openvswitch kernel
due to a duplicated name "dst_cache_destroy". For most cases the
"USE_UPSTREAM_TUNNEL" covers this but in this case the dst_cache
feature needs to be separated out.
Add the necessary compatibility detection layer in acinclude.m4 and
then fixup the source files so that if the built-in kernel includes
dst_cache support then exclude our own compatibility code.
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Acked-by: Pravin B Shelar <pshelar@ovn.org>
This backports dst-cache implementation from upstream implementation.
commit 911362c70df5b766c243dc297fadeaced786ffd8
Author: Paolo Abeni <pabeni@redhat.com>
net: add dst_cache support
This patch add a generic, lockless dst cache implementation.
The need for lock is avoided updating the dst cache fields
only in per cpu scope, and requiring that the cache manipulation
functions are invoked with the local bh disabled.
The refresh_ts and reset_ts fields are used to ensure the cache
consistency in case of cuncurrent cache update (dst_cache_set*) and
reset operation (dst_cache_reset).
Consider the following scenario:
CPU1: CPU2:
<cache lookup with emtpy cache: it fails>
<get dst via uncached route lookup>
<related configuration changes>
dst_cache_reset()
dst_cache_set()
The dst entry set passed to dst_cache_set() should not be used
for later dst cache lookup, because it's obtained using old
configuration values.
Since the refresh_ts is updated only on dst_cache lookup, the
cached value in the above scenario will be discarded on the next
lookup.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Suggested-and-acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Acked-by: Jesse Gross <jesse@kernel.org>
