1 files changed, 35 insertions, 43 deletions

diff --git a/fs/nfsd/nfscache.c b/fs/nfsd/nfscache.c
index e76244edd74..6040da8830f 100644
--- a/fs/nfsd/nfscache.c
+++ b/fs/nfsd/nfscache.c
@@ -59,11 +59,14 @@ static unsigned int		longest_chain_cachesize;
 
 static int	nfsd_cache_append(struct svc_rqst *rqstp, struct kvec *vec);
 static void	cache_cleaner_func(struct work_struct *unused);
-static int 	nfsd_reply_cache_shrink(struct shrinker *shrink,
-					struct shrink_control *sc);
+static unsigned long nfsd_reply_cache_count(struct shrinker *shrink,
+					    struct shrink_control *sc);
+static unsigned long nfsd_reply_cache_scan(struct shrinker *shrink,
+					   struct shrink_control *sc);
 
 static struct shrinker nfsd_reply_cache_shrinker = {
-	.shrink	= nfsd_reply_cache_shrink,
+	.scan_objects = nfsd_reply_cache_scan,
+	.count_objects = nfsd_reply_cache_count,
 	.seeks	= 1,
 };
 
@@ -221,27 +224,28 @@ hash_refile(struct svc_cacherep *rp)
 	hlist_add_head(&rp->c_hash, cache_hash + hash_32(rp->c_xid, maskbits));
 }
 
-static inline bool
-nfsd_cache_entry_expired(struct svc_cacherep *rp)
-{
-	return rp->c_state != RC_INPROG &&
-	       time_after(jiffies, rp->c_timestamp + RC_EXPIRE);
-}
-
 /*
  * Walk the LRU list and prune off entries that are older than RC_EXPIRE.
  * Also prune the oldest ones when the total exceeds the max number of entries.
  */
-static void
+static long
 prune_cache_entries(void)
 {
 	struct svc_cacherep *rp, *tmp;
+	long freed = 0;
 
 	list_for_each_entry_safe(rp, tmp, &lru_head, c_lru) {
-		if (!nfsd_cache_entry_expired(rp) &&
-		    num_drc_entries <= max_drc_entries)
+		/*
+		 * Don't free entries attached to calls that are still
+		 * in-progress, but do keep scanning the list.
+		 */
+		if (rp->c_state == RC_INPROG)
+			continue;
+		if (num_drc_entries <= max_drc_entries &&
+		    time_before(jiffies, rp->c_timestamp + RC_EXPIRE))
 			break;
 		nfsd_reply_cache_free_locked(rp);
+		freed++;
 	}
 
 	/*
@@ -254,6 +258,7 @@ prune_cache_entries(void)
 		cancel_delayed_work(&cache_cleaner);
 	else
 		mod_delayed_work(system_wq, &cache_cleaner, RC_EXPIRE);
+	return freed;
 }
 
 static void
@@ -264,20 +269,28 @@ cache_cleaner_func(struct work_struct *unused)
 	spin_unlock(&cache_lock);
 }
 
-static int
-nfsd_reply_cache_shrink(struct shrinker *shrink, struct shrink_control *sc)
+static unsigned long
+nfsd_reply_cache_count(struct shrinker *shrink, struct shrink_control *sc)
 {
-	unsigned int num;
+	unsigned long num;
 
 	spin_lock(&cache_lock);
-	if (sc->nr_to_scan)
-		prune_cache_entries();
 	num = num_drc_entries;
 	spin_unlock(&cache_lock);
 
 	return num;
 }
 
+static unsigned long
+nfsd_reply_cache_scan(struct shrinker *shrink, struct shrink_control *sc)
+{
+	unsigned long freed;
+
+	spin_lock(&cache_lock);
+	freed = prune_cache_entries();
+	spin_unlock(&cache_lock);
+	return freed;
+}
 /*
  * Walk an xdr_buf and get a CRC for at most the first RC_CSUMLEN bytes
  */
@@ -395,22 +408,8 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 
 	/*
 	 * Since the common case is a cache miss followed by an insert,
-	 * preallocate an entry. First, try to reuse the first entry on the LRU
-	 * if it works, then go ahead and prune the LRU list.
+	 * preallocate an entry.
 	 */
-	spin_lock(&cache_lock);
-	if (!list_empty(&lru_head)) {
-		rp = list_first_entry(&lru_head, struct svc_cacherep, c_lru);
-		if (nfsd_cache_entry_expired(rp) ||
-		    num_drc_entries >= max_drc_entries) {
-			lru_put_end(rp);
-			prune_cache_entries();
-			goto search_cache;
-		}
-	}
-
-	/* No expired ones available, allocate a new one. */
-	spin_unlock(&cache_lock);
 	rp = nfsd_reply_cache_alloc();
 	spin_lock(&cache_lock);
 	if (likely(rp)) {
@@ -418,7 +417,9 @@ nfsd_cache_lookup(struct svc_rqst *rqstp)
 		drc_mem_usage += sizeof(*rp);
 	}
 
-search_cache:
+	/* go ahead and prune the cache */
+	prune_cache_entries();
+
 	found = nfsd_cache_search(rqstp, csum);
 	if (found) {
 		if (likely(rp))
@@ -432,15 +433,6 @@ search_cache:
 		goto out;
 	}
 
-	/*
-	 * We're keeping the one we just allocated. Are we now over the
-	 * limit? Prune one off the tip of the LRU in trade for the one we
-	 * just allocated if so.
-	 */
-	if (num_drc_entries >= max_drc_entries)
-		nfsd_reply_cache_free_locked(list_first_entry(&lru_head,
-						struct svc_cacherep, c_lru));
-
 	nfsdstats.rcmisses++;
 	rqstp->rq_cacherep = rp;
 	rp->c_state = RC_INPROG;