From 75a077fa0ee4b0094b6d43619cd0a068a82ebfd7 Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org.ua>
Date: Sun, 6 Aug 2017 18:14:55 +0300
Subject: Switch to POSIX pthread_rwlock functions instead of the custom locker

---
 src/vmod_dict.c | 92 ++++++++-------------------------------------------------
 1 file changed, 12 insertions(+), 80 deletions(-)

(limited to 'src/vmod_dict.c')

diff --git a/src/vmod_dict.c b/src/vmod_dict.c
index 5875abd..04ee52c 100644
--- a/src/vmod_dict.c
+++ b/src/vmod_dict.c
@@ -74,75 +74,7 @@ static size_t hash_size;
 static struct entry **hash_table;
 static size_t max_hash_size = 8192;
 static ssize_t max_coll = -1; /* Max. number of collisions allowed */
-
-typedef struct {
-	size_t readers;
-	size_t writer;
-	pthread_mutex_t mutex;
-	pthread_cond_t lock_free;
-} locker_t;
-
-static locker_t rwlock;
-
-static void
-locker_init(locker_t *rdwr)
-{
-	rdwr->readers = 0;
-	rdwr->writer = 0;
-	pthread_mutex_init(&rdwr->mutex, NULL);
-	pthread_cond_init(&rdwr->lock_free, NULL);
-}
-
-static void
-locker_rlock(locker_t *rdwr)
-{
-	pthread_mutex_lock(&rdwr->mutex);
-	while (rdwr->writer) 
-		pthread_cond_wait(&rdwr->lock_free, &rdwr->mutex);
-	rdwr->readers++;
-	pthread_mutex_unlock(&rdwr->mutex);
-}
-
-static void
-locker_wlock(locker_t *rdwr)
-{
-	pthread_mutex_lock(&rdwr->mutex);
-	while (rdwr->writer || rdwr->readers) 
-		pthread_cond_wait(&rdwr->lock_free, &rdwr->mutex);
-	rdwr->writer++;
-	pthread_mutex_unlock(&rdwr->mutex);
-}
-
-static int
-locker_runlock(locker_t *rdwr)
-{
-	pthread_mutex_lock(&rdwr->mutex);
-	if (rdwr->readers == 0) {
-		pthread_mutex_unlock(&rdwr->mutex);
-		return -1;
-	} else {
-		rdwr->readers--;
-		if (rdwr->readers == 0)
-			pthread_cond_signal(&rdwr->lock_free);
-		pthread_mutex_unlock(&rdwr->mutex);
-		return 0;
-	}
-}
-
-static int
-locker_wunlock(locker_t *rdwr)
-{
-	pthread_mutex_lock(&rdwr->mutex);
-	if (rdwr->writer == 0) {
-		pthread_mutex_unlock(&rdwr->mutex);
-		return -1;
-	} else {
-		rdwr->writer = 0;
-		pthread_cond_signal(&rdwr->lock_free);
-		pthread_mutex_unlock(&rdwr->mutex);
-		return 0;
-	}
-}
+static pthread_rwlock_t rwlock;
 
 static int cs_coll[] = {
 	0,   1,   2,   3,   4,   5,   6,   7,
@@ -440,17 +372,17 @@ dict_event(VRT_CTX, struct vmod_priv *priv, enum vcl_event_e e)
 {
 	switch (e) {
 	case VCL_EVENT_LOAD:
-		locker_init(&rwlock);
+		pthread_rwlock_init(&rwlock, NULL);
 		break;
 
 	case VCL_EVENT_DISCARD:
-		locker_wlock(&rwlock);
+		pthread_rwlock_wrlock(&rwlock);
 		while (ent_head)
 			entry_remove(ent_head);
 		free(hash_table);
 		hash_table = NULL;
 		hash_size = 0;
-		locker_wunlock(&rwlock);
+		pthread_rwlock_unlock(&rwlock);
 		break;
 		
 	case VCL_EVENT_WARM:
@@ -464,14 +396,14 @@ VCL_VOID
 vmod_ci(VRT_CTX, VCL_BOOL ci)
 {
 	int *cp;
-	locker_wlock(&rwlock);
+	pthread_rwlock_wrlock(&rwlock);
         cp = ci ? ci_coll : cs_coll;
 	if (cp != collation) {
 		collation = cp;
 		rehash();
 		fill_table();
 	}
-	locker_wunlock(&rwlock);
+	pthread_rwlock_unlock(&rwlock);
 }
 
 VCL_VOID
@@ -483,10 +415,10 @@ vmod_collisions(VRT_CTX, VCL_INT coll)
 VCL_VOID
 vmod_load(VRT_CTX, VCL_STRING file)
 {
-	locker_wlock(&rwlock);
+	pthread_rwlock_wrlock(&rwlock);
 	load_entries(file);
 	fill_table();
-	locker_wunlock(&rwlock);
+	pthread_rwlock_unlock(&rwlock);
 }
 
 VCL_VOID
@@ -494,12 +426,12 @@ vmod_clear(VRT_CTX)
 {
 	size_t i;
 	
-	locker_wlock(&rwlock);
+	pthread_rwlock_wrlock(&rwlock);
 	for (i = 0; i < hash_size; i++)
 		hash_table[i] = NULL;
 	while (ent_head)
 		entry_remove(ent_head);
-	locker_wunlock(&rwlock);
+	pthread_rwlock_unlock(&rwlock);
 }	
 
 static char const *
@@ -530,13 +462,13 @@ vmod_lookup(VRT_CTX, VCL_STRING key)
 {
 	char *s = NULL;
 	if (key) {
-		locker_rlock(&rwlock);
+		pthread_rwlock_rdlock(&rwlock);
 		char const *p = lookup_unlocked(key);
 		if (p) {
 			s = WS_Copy(ctx->ws, p, -1);
 			AN(s);
 		}
-		locker_runlock(&rwlock);
+		pthread_rwlock_unlock(&rwlock);
 	}
 	return s;
 }
-- 
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