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ipv6: Refactor fib6_drop_pcpu_from 

Move the existing pcpu walk in fib6_drop_pcpu_from to a new
helper, __fib6_drop_pcpu_from, that can be invoked per fib6_nh with a
reference to the from entries that need to be evicted. If the passed
in 'from' is non-NULL then only entries associated with that fib6_info
are removed (e.g., case where fib entry is deleted); if the 'from' is
NULL are entries are flushed (e.g., fib6_nh is deleted).

For fib6_info entries with builtin fib6_nh (ie., current code) there
is no change in behavior.

Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David Ahern 2019-05-22 20:27:56 -07:00 committed by David S. Miller
parent f40b6ae2b6
commit 7d88d8b557
1 changed files with 25 additions and 10 deletions
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35
net/ipv6/ip6_fib.c
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@ -874,21 +874,15 @@ static struct fib6_node *fib6_add_1(struct net *net,
return ln;
}
static void fib6_drop_pcpu_from(struct fib6_info *f6i,
const struct fib6_table *table)
static void __fib6_drop_pcpu_from(struct fib6_nh *fib6_nh,
const struct fib6_info *match,
const struct fib6_table *table)
{
struct fib6_nh *fib6_nh = &f6i->fib6_nh;
int cpu;
if (!fib6_nh->rt6i_pcpu)
return;
/* Make sure rt6_make_pcpu_route() wont add other percpu routes
* while we are cleaning them here.
*/
f6i->fib6_destroying = 1;
mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
/* release the reference to this fib entry from
* all of its cached pcpu routes
*/
@ -898,7 +892,13 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i,
ppcpu_rt = per_cpu_ptr(fib6_nh->rt6i_pcpu, cpu);
pcpu_rt = *ppcpu_rt;
if (pcpu_rt) {
/* only dropping the 'from' reference if the cached route
* is using 'match'. The cached pcpu_rt->from only changes
* from a fib6_info to NULL (ip6_dst_destroy); it can never
* change from one fib6_info reference to another
*/
if (pcpu_rt && rcu_access_pointer(pcpu_rt->from) == match) {
struct fib6_info *from;
from = xchg((__force struct fib6_info **)&pcpu_rt->from, NULL);
@ -907,6 +907,21 @@ static void fib6_drop_pcpu_from(struct fib6_info *f6i,
}
}
static void fib6_drop_pcpu_from(struct fib6_info *f6i,
const struct fib6_table *table)
{
struct fib6_nh *fib6_nh;
/* Make sure rt6_make_pcpu_route() wont add other percpu routes
* while we are cleaning them here.
*/
f6i->fib6_destroying = 1;
mb(); /* paired with the cmpxchg() in rt6_make_pcpu_route() */
fib6_nh = &f6i->fib6_nh;
__fib6_drop_pcpu_from(fib6_nh, f6i, table);
}
static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn,
struct net *net)
{