From: Trond Myklebust <trondmy@gmail.com>
Date: Sun, 1 Mar 2020 23:21:43 +0000 (-0500)
Subject: SUNRPC/cache: Allow garbage collection of invalid cache entries
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=277f27e2f277;p=linux.git

SUNRPC/cache: Allow garbage collection of invalid cache entries

If the cache entry never gets initialised, we want the garbage
collector to be able to evict it. Otherwise if the upcall daemon
fails to initialise the entry, we end up never expiring it.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
[ cel: resolved a merge conflict ]
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---

diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
index 656882a50991e..532cdbda43da0 100644
--- a/include/linux/sunrpc/cache.h
+++ b/include/linux/sunrpc/cache.h
@@ -209,9 +209,6 @@ static inline void cache_put(struct cache_head *h, struct cache_detail *cd)
 
 static inline bool cache_is_expired(struct cache_detail *detail, struct cache_head *h)
 {
-	if (!test_bit(CACHE_VALID, &h->flags))
-		return false;
-
 	return  (h->expiry_time < seconds_since_boot()) ||
 		(detail->flush_time >= h->last_refresh);
 }
diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
index 7f2e5d818e05e..cd76ef2d26b82 100644
--- a/net/sunrpc/cache.c
+++ b/net/sunrpc/cache.c
@@ -64,13 +64,14 @@ static struct cache_head *sunrpc_cache_find_rcu(struct cache_detail *detail,
 
 	rcu_read_lock();
 	hlist_for_each_entry_rcu(tmp, head, cache_list) {
-		if (detail->match(tmp, key)) {
-			if (cache_is_expired(detail, tmp))
-				continue;
-			tmp = cache_get_rcu(tmp);
-			rcu_read_unlock();
-			return tmp;
-		}
+		if (!detail->match(tmp, key))
+			continue;
+		if (test_bit(CACHE_VALID, &tmp->flags) &&
+		    cache_is_expired(detail, tmp))
+			continue;
+		tmp = cache_get_rcu(tmp);
+		rcu_read_unlock();
+		return tmp;
 	}
 	rcu_read_unlock();
 	return NULL;
@@ -114,17 +115,18 @@ static struct cache_head *sunrpc_cache_add_entry(struct cache_detail *detail,
 	/* check if entry appeared while we slept */
 	hlist_for_each_entry_rcu(tmp, head, cache_list,
 				 lockdep_is_held(&detail->hash_lock)) {
-		if (detail->match(tmp, key)) {
-			if (cache_is_expired(detail, tmp)) {
-				sunrpc_begin_cache_remove_entry(tmp, detail);
-				freeme = tmp;
-				break;
-			}
-			cache_get(tmp);
-			spin_unlock(&detail->hash_lock);
-			cache_put(new, detail);
-			return tmp;
+		if (!detail->match(tmp, key))
+			continue;
+		if (test_bit(CACHE_VALID, &tmp->flags) &&
+		    cache_is_expired(detail, tmp)) {
+			sunrpc_begin_cache_remove_entry(tmp, detail);
+			freeme = tmp;
+			break;
 		}
+		cache_get(tmp);
+		spin_unlock(&detail->hash_lock);
+		cache_put(new, detail);
+		return tmp;
 	}
 
 	hlist_add_head_rcu(&new->cache_list, head);