From: Yang Erkun <yangerkun@xxxxxxxxxx>
rcu_read_lock/rcu_read_unlock has already protect any ptr we will
when we call c_show. No need get cache ref. Besides, cache_put may drop
the last ref for cache_head, and the .put like expkey_put/svc_export_put
will call dput, which may sleep, and this will break rcu protection.
Fixes: ae74136b4bb6 ("SUNRPC: Allow cache lookups to use RCU protection rather than the r/w spinlock")
Signed-off-by: Yang Erkun <yangerkun@xxxxxxxxxx>
---
net/sunrpc/cache.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index eaf4defd1fcf..01745a6f595d 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -1425,18 +1425,12 @@ static int c_show(struct seq_file *m, void *p)
seq_printf(m, "# expiry=%lld refcnt=%d flags=%lx\n",
convert_to_wallclock(cp->expiry_time),
kref_read(&cp->ref), cp->flags);
- if (!cache_get_rcu(cp))
- return 0;
- if (cache_check(cd, cp, NULL)) {
- cache_put(cp, cd);
+ if (cache_check(cd, cp, NULL))
/* cache_check does a cache_put on failure */
seq_puts(m, "# ");
- } else {
- if (cache_is_expired(cd, cp))
- seq_puts(m, "# ");
- cache_put(cp, cd);
- }
+ else if (cache_is_expired(cd, cp))
+ seq_puts(m, "# ");
return cd->cache_show(m, cd, cp);
}
--
2.39.2
