netfilter: nf_tables: add GC synchronization helpers
GC is expected to happen asynchrously to the netlink interface. In the netlink path, both insertion and removal of elements consist of two steps, insertion followed by activation or deactivation followed by removal, during which the element must not be freed by GC. The synchronization helpers use an unused bit in the genmask field to atomically mark an element as "busy", meaning it is either currently being handled through the netlink API or by GC. Elements being processed by GC will never survive, netlink will simply ignore them. Elements being currently processed through netlink will be skipped by GC and reprocessed during the next run. Signed-off-by:Patrick McHardy <kaber@trash.net> Signed-off-by:
Pablo Neira Ayuso <pablo@netfilter.org>
parent
cfed7e1b
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