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Date: Fri, 8 Dec 2023 15:43:38 -0700
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Subject: Re: [PATCH net-next v2 1/2] net/ipv6: insert a f6i to a GC list only
 if the f6i is in a fib6_table tree.
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To: thinker.li@gmail.com, netdev@vger.kernel.org, martin.lau@linux.dev,
 kernel-team@meta.com, davem@davemloft.net, kuba@kernel.org,
 pabeni@redhat.com, edumazet@google.com
Cc: sinquersw@gmail.com, kuifeng@meta.com,
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References: <20231208194523.312416-1-thinker.li@gmail.com>
 <20231208194523.312416-2-thinker.li@gmail.com>
From: David Ahern <dsahern@kernel.org>
In-Reply-To: <20231208194523.312416-2-thinker.li@gmail.com>
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On 12/8/23 12:45 PM, thinker.li@gmail.com wrote:
> From: Kui-Feng Lee <thinker.li@gmail.com>
> 
> Check f6i->fib6_node and hlist_unhashed(&f6i->gc_link) before inserting a
> f6i (fib6_info) to tb6_gc_hlist.
> 
> The current implementation checks if f6i->fib6_table is not NULL to
> determines if a f6i is on a tree, however it is not enough. When a f6i is
> removed from a fib6_table, f6i->fib6_table is not reset. However, fib6_node
> is always reset when a f6i is removed from a fib6_table and is set when a
> f6i is added to a fib6_table. So, f6i->fib6_node is a reliable way to
> determine if a f6i is on a tree.

Which is an indication that the table is not the right check but neither
is the fib6_node. If expires is set on a route entry, add it to the
gc_list; if expires is reset on a route entry, remove it from the
gc_list. If the value of expires is changed while on the gc_list list,
just update the expires value.