Simplify caching of thread-specific bitmaps for random_bool().

src/vmod_gcrypt.c

@@ -90,21 +90,24 @@ struct filedata {
 	size_t			len;
 };
 
-struct rnd_bool {
-	unsigned	magic;
-#define VMOD_GCRYPT_RND_BOOL_MAGIC 0x7d0a3e42
+struct rnd_bitmap {
 	uint64_t	bits;
 	uint8_t		nbits;
 };
 
+struct rnd_bool {
+	unsigned		magic;
+#define VMOD_GCRYPT_RND_BOOL_MAGIC 0x7d0a3e42
+	struct rnd_bitmap	bitmap[2];
+};
+
 VSLIST_HEAD(filedata_head, filedata);
 
 static const char *gcrypt_version = NULL;
 static int secmem_enabled = 1;
-static pthread_once_t strong_bool_once = PTHREAD_ONCE_INIT,
-	nonce_bool_once = PTHREAD_ONCE_INIT;
-static pthread_key_t strong_boolk, nonce_boolk;
-static int strong_boolk_inited = 0, nonce_boolk_inited = 0;
+static pthread_once_t rnd_bool_once = PTHREAD_ONCE_INIT;
+static pthread_key_t rnd_boolk;
+static int rnd_boolk_inited = 0;
 
 static void
 errmsg(VRT_CTX, const char *fmt, ...)
@@ -832,73 +835,43 @@ rnd_bool_fini(void *p)
 }
 
 /*
- * Initialize the pthread key for both quality levels via pthread_once,
- * only if random_bool() is called for that quality level at all.
+ * Initialize the pthread key for the cached bitmaps via pthread_once,
+ * only if random_bool() is called at all.
  */
-
 static void
-nonce_bool_init(void)
+rnd_bool_init(void)
 {
-	AZ(nonce_boolk_inited);
+	AZ(rnd_boolk_inited);
 	errno = 0;
-	if (pthread_key_create(&nonce_boolk, rnd_bool_fini) != 0) {
+	if (pthread_key_create(&rnd_boolk, rnd_bool_fini) != 0) {
 		assert(errno == EAGAIN);
 		return;
 	}
-	nonce_boolk_inited = 1;
-}
-
-static void
-strong_bool_init(void)
-{
-	AZ(strong_boolk_inited);
-	errno = 0;
-	if (pthread_key_create(&strong_boolk, rnd_bool_fini) != 0) {
-		assert(errno == EAGAIN);
-		return;
-	}
-	strong_boolk_inited = 1;
+	rnd_boolk_inited = 1;
 }
 
 VCL_BOOL
 vmod_random_bool(VRT_CTX, VCL_ENUM qualitys)
 {
 	VCL_BOOL r;
-	pthread_once_t *rnd_bool_once;
-	void (*rnd_bool_init)(void);
-	pthread_key_t *rnd_boolk;
-	int *rnd_boolk_inited;
 	void *p;
 	struct rnd_bool *rb;
+	int map = 0;
 
 	CHECK_OBJ_NOTNULL(ctx, VRT_CTX_MAGIC);
 	AN(qualitys);
 	assert(qualitys[0] != 'V');
 
-	switch(qualitys[0]) {
-	case 'N':
-		rnd_bool_once = &nonce_bool_once;
-		rnd_bool_init = nonce_bool_init;
-		rnd_boolk = &nonce_boolk;
-		rnd_boolk_inited = &nonce_boolk_inited;
-		break;
-	case 'S':
-		rnd_bool_once = &strong_bool_once;
-		rnd_bool_init = strong_bool_init;
-		rnd_boolk = &strong_boolk;
-		rnd_boolk_inited = &strong_boolk_inited;
-		break;
-	default:
-		WRONG("Invalid quality ENUM");
-	}
-	AZ(pthread_once(rnd_bool_once, rnd_bool_init));
-	if (! *rnd_boolk_inited) {
+	if (qualitys[0] == 'S')
+		map = 1;
+	AZ(pthread_once(&rnd_bool_once, rnd_bool_init));
+	if (! rnd_boolk_inited) {
 		VERR(ctx, "pthread key allocation exhausted "
 		     "(PTHREAD_KEYS_MAX=%d) in gcrypt.random_bool(), discard "
 		     "old VCL instances or restart Varnish", PTHREAD_KEYS_MAX);
 		return 0;
 	}
-	p = pthread_getspecific(*rnd_boolk);
+	p = pthread_getspecific(rnd_boolk);
 	if (p == NULL) {
 		ALLOC_OBJ(rb, VMOD_GCRYPT_RND_BOOL_MAGIC);
 		if (rb == NULL) {
@@ -906,20 +879,19 @@ vmod_random_bool(VRT_CTX, VCL_ENUM qualitys)
 				 "for random_bool()");
 			return 0;
 		}
-		AZ(rb->bits);
-		AZ(rb->nbits);
-		AZ(pthread_setspecific(*rnd_boolk, rb));
+		AZ(pthread_setspecific(rnd_boolk, rb));
 	}
 	else
 		CAST_OBJ(rb, p, VMOD_GCRYPT_RND_BOOL_MAGIC);
 
-	if (rb->nbits == 0) {
-		get_rnd(qualitys, &rb->bits, sizeof(rb->bits));
-		rb->nbits = sizeof(rb->bits) * 8;
+	if (rb->bitmap[map].nbits == 0) {
+		get_rnd(qualitys, &rb->bitmap[map].bits,
+			sizeof(rb->bitmap[map].bits));
+		rb->bitmap[map].nbits = sizeof(rb->bitmap[map].bits) * 8;
 	}
-	r = rb->bits & 0x01;
-	rb->bits >>= 1;
-	rb->nbits -= 1;
+	r = rb->bitmap[map].bits & 0x01;
+	rb->bitmap[map].bits >>= 1;
+	rb->bitmap[map].nbits -= 1;
 	return r;
 }