Astobj2 locking enhancement.

Add the ability to specify what kind of locking an ao2 object has when it
is allocated.  The locking could be one of: MUTEX, RWLOCK, or none.

New API:

ao2_t_alloc_options()
ao2_alloc_options()
ao2_t_container_alloc_options()
ao2_container_alloc_options()

ao2_rdlock()
ao2_wrlock()
ao2_tryrdlock()
ao2_trywrlock()

The OBJ_NOLOCK and AO2_ITERATOR_DONTLOCK flags have a slight meaning
change.  They no longer mean that the object is protected by an external
mechanism.  They mean the lock associated with the object has already been
manually obtained by one of the ao2_lock calls.  This change is necessary
for RWLOCK support since they are not reentrant.  Also an operation on an
ao2 container may require promoting a read lock to a write lock by
releasing the already held read lock to re-acquire as a write lock.


Replaced API calls:

ao2_t_link_nolock()
ao2_link_nolock()
ao2_t_unlink_nolock()
ao2_unlink_nolock()

with the respective

ao2_t_link_flags()
ao2_link_flags()
ao2_t_unlink_flags()
ao2_unlink_flags()

API calls to be more flexible and to allow an anticipated enhancement to
control linking duplicate objects into a container.


The changes to format.c and format_cap.c are taking advantange of the new
ao2 locking options to simplify the use of the format capabilities
containers.

Review: https://reviewboard.asterisk.org/r/1554/


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@357272 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 33 insertions, 34 deletions

diff --git a/main/format_cap.c b/main/format_cap.c
index bd471d4a7..ffec45fe2 100644
--- a/main/format_cap.c
+++ b/main/format_cap.c
@@ -39,6 +39,7 @@ struct ast_format_cap {
 	/* The capabilities structure is just an ao2 container of ast_formats */
 	struct ao2_container *formats;
 	struct ao2_iterator it;
+	/*! TRUE if the formats container created without a lock. */
 	int nolock;
 };
 
@@ -69,8 +70,11 @@ static struct ast_format_cap *cap_alloc_helper(int nolock)
 	if (!cap) {
 		return NULL;
 	}
-	cap->nolock = nolock ? OBJ_NOLOCK : 0;
-	if (!(cap->formats = ao2_container_alloc(283, hash_cb, cmp_cb))) {
+	cap->nolock = nolock;
+	cap->formats = ao2_container_alloc_options(
+		nolock ? AO2_ALLOC_OPT_LOCK_NOLOCK : AO2_ALLOC_OPT_LOCK_MUTEX,
+		283, hash_cb, cmp_cb);
+	if (!cap->formats) {
 		ast_free(cap);
 		return NULL;
 	}
@@ -109,11 +113,7 @@ void ast_format_cap_add(struct ast_format_cap *cap, const struct ast_format *for
 		return;
 	}
 	ast_format_copy(fnew, format);
-	if (cap->nolock) {
-		ao2_link_nolock(cap->formats, fnew);
-	} else {
-		ao2_link(cap->formats, fnew);
-	}
+	ao2_link(cap->formats, fnew);
 	ao2_ref(fnew, -1);
 }
 
@@ -157,7 +157,7 @@ static int append_cb(void *obj, void *arg, int flag)
 
 void ast_format_cap_append(struct ast_format_cap *dst, const struct ast_format_cap *src)
 {
-	ao2_callback(src->formats, OBJ_NODATA | src->nolock, append_cb, dst);
+	ao2_callback(src->formats, OBJ_NODATA, append_cb, dst);
 }
 
 static int copy_cb(void *obj, void *arg, int flag)
@@ -172,7 +172,7 @@ static int copy_cb(void *obj, void *arg, int flag)
 void ast_format_cap_copy(struct ast_format_cap *dst, const struct ast_format_cap *src)
 {
 	ast_format_cap_remove_all(dst);
-	ao2_callback(src->formats, OBJ_NODATA | src->nolock, copy_cb, dst);
+	ao2_callback(src->formats, OBJ_NODATA, copy_cb, dst);
 }
 
 struct ast_format_cap *ast_format_cap_dup(const struct ast_format_cap *cap)
@@ -186,7 +186,7 @@ struct ast_format_cap *ast_format_cap_dup(const struct ast_format_cap *cap)
 	if (!dst) {
 		return NULL;
 	}
-	ao2_callback(cap->formats, OBJ_NODATA | cap->nolock, copy_cb, dst);
+	ao2_callback(cap->formats, OBJ_NODATA, copy_cb, dst);
 	return dst;
 }
 
@@ -209,8 +209,8 @@ static int find_exact_cb(void *obj, void *arg, int flag)
 int ast_format_cap_remove(struct ast_format_cap *cap, struct ast_format *format)
 {
 	struct ast_format *fremove;
-	fremove = ao2_callback(cap->formats, OBJ_POINTER | OBJ_UNLINK | cap->nolock, find_exact_cb, format);
 
+	fremove = ao2_callback(cap->formats, OBJ_POINTER | OBJ_UNLINK, find_exact_cb, format);
 	if (fremove) {
 		ao2_ref(fremove, -1);
 		return 0;
@@ -249,7 +249,7 @@ int ast_format_cap_remove_byid(struct ast_format_cap *cap, enum ast_format_id id
 	};
 
 	ao2_callback(cap->formats,
-		OBJ_NODATA | cap->nolock | OBJ_MULTIPLE | OBJ_UNLINK,
+		OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK,
 		multiple_by_id_cb,
 		&data);
 
@@ -271,14 +271,14 @@ static int multiple_by_type_cb(void *obj, void *arg, int flag)
 void ast_format_cap_remove_bytype(struct ast_format_cap *cap, enum ast_format_type type)
 {
 	ao2_callback(cap->formats,
-		OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE | cap->nolock,
+		OBJ_UNLINK | OBJ_NODATA | OBJ_MULTIPLE,
 		multiple_by_type_cb,
 		&type);
 }
 
 void ast_format_cap_remove_all(struct ast_format_cap *cap)
 {
-	ao2_callback(cap->formats, OBJ_NODATA | cap->nolock | OBJ_MULTIPLE | OBJ_UNLINK, NULL, NULL);
+	ao2_callback(cap->formats, OBJ_NODATA | OBJ_MULTIPLE | OBJ_UNLINK, NULL, NULL);
 }
 
 void ast_format_cap_set(struct ast_format_cap *cap, struct ast_format *format)
@@ -291,8 +291,8 @@ int ast_format_cap_get_compatible_format(const struct ast_format_cap *cap, const
 {
 	struct ast_format *f;
 	struct ast_format_cap *tmp_cap = (struct ast_format_cap *) cap;
-	f = ao2_find(tmp_cap->formats, (struct ast_format *) format, OBJ_POINTER | tmp_cap->nolock);
 
+	f = ao2_find(tmp_cap->formats, format, OBJ_POINTER);
 	if (f) {
 		ast_format_copy(result, f);
 		ao2_ref(f, -1);
@@ -310,7 +310,8 @@ int ast_format_cap_iscompatible(const struct ast_format_cap *cap, const struct a
 	if (!tmp_cap) {
 		return 0;
 	}
-	f = ao2_find(tmp_cap->formats, (struct ast_format *) format, OBJ_POINTER | tmp_cap->nolock);
+
+	f = ao2_find(tmp_cap->formats, format, OBJ_POINTER);
 	if (f) {
 		ao2_ref(f, -1);
 		return 1;
@@ -345,7 +346,7 @@ int ast_format_cap_best_byid(const struct ast_format_cap *cap, enum ast_format_i
 
 	ast_format_clear(result);
 	ao2_callback(cap->formats,
-		OBJ_MULTIPLE | OBJ_NODATA | cap->nolock,
+		OBJ_MULTIPLE | OBJ_NODATA,
 		find_best_byid_cb,
 		&data);
 	return result->id ? 1 : 0;
@@ -389,11 +390,11 @@ int ast_format_cap_has_joint(const struct ast_format_cap *cap1, const struct ast
 		.joint_cap = NULL,
 	};
 
-	it = ao2_iterator_init(cap1->formats, cap1->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap1->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		data.format = tmp;
 		ao2_callback(cap2->formats,
-			OBJ_MULTIPLE | OBJ_NODATA | cap2->nolock,
+			OBJ_MULTIPLE | OBJ_NODATA,
 			find_joint_cb,
 			&data);
 		ao2_ref(tmp, -1);
@@ -412,7 +413,7 @@ int ast_format_cap_identical(const struct ast_format_cap *cap1, const struct ast
 		return 0; /* if they are not the same size, they are not identical */
 	}
 
-	it = ao2_iterator_init(cap1->formats, cap1->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap1->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		if (!ast_format_cap_iscompatible(cap2, tmp)) {
 			ao2_ref(tmp, -1);
@@ -439,11 +440,11 @@ struct ast_format_cap *ast_format_cap_joint(const struct ast_format_cap *cap1, c
 		return NULL;
 	}
 
-	it = ao2_iterator_init(cap1->formats, cap1->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap1->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		data.format = tmp;
 		ao2_callback(cap2->formats,
-			OBJ_MULTIPLE | OBJ_NODATA | cap2->nolock,
+			OBJ_MULTIPLE | OBJ_NODATA,
 			find_joint_cb,
 			&data);
 		ao2_ref(tmp, -1);
@@ -469,11 +470,11 @@ static int joint_copy_helper(const struct ast_format_cap *cap1, const struct ast
 	if (!append) {
 		ast_format_cap_remove_all(result);
 	}
-	it = ao2_iterator_init(cap1->formats, cap1->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap1->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		data.format = tmp;
 		ao2_callback(cap2->formats,
-			OBJ_MULTIPLE | OBJ_NODATA | cap2->nolock,
+			OBJ_MULTIPLE | OBJ_NODATA,
 			find_joint_cb,
 			&data);
 		ao2_ref(tmp, -1);
@@ -505,7 +506,7 @@ struct ast_format_cap *ast_format_cap_get_type(const struct ast_format_cap *cap,
 
 	/* for each format in cap1, see if that format is
 	 * compatible with cap2. If so copy it to the result */
-	it = ao2_iterator_init(cap->formats, cap->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		if (AST_FORMAT_GET_TYPE(tmp->id) == ftype) {
 			/* copy format */
@@ -529,7 +530,7 @@ int ast_format_cap_has_type(const struct ast_format_cap *cap, enum ast_format_ty
 	struct ao2_iterator it;
 	struct ast_format *tmp;
 
-	it = ao2_iterator_init(cap->formats, cap->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		if (AST_FORMAT_GET_TYPE(tmp->id) == type) {
 			ao2_ref(tmp, -1);
@@ -545,18 +546,16 @@ int ast_format_cap_has_type(const struct ast_format_cap *cap, enum ast_format_ty
 
 void ast_format_cap_iter_start(struct ast_format_cap *cap)
 {
-	if (!cap->nolock) {
-		ao2_lock(cap->formats);
-	}
-	cap->it = ao2_iterator_init(cap->formats, cap->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	/* We can unconditionally lock even if the container has no lock. */
+	ao2_lock(cap->formats);
+	cap->it = ao2_iterator_init(cap->formats, AO2_ITERATOR_DONTLOCK);
 }
 
 void ast_format_cap_iter_end(struct ast_format_cap *cap)
 {
 	ao2_iterator_destroy(&cap->it);
-	if (!cap->nolock) {
-		ao2_unlock(cap->formats);
-	}
+	/* We can unconditionally unlock even if the container has no lock. */
+	ao2_unlock(cap->formats);
 }
 
 int ast_format_cap_iter_next(struct ast_format_cap *cap, struct ast_format *format)
@@ -614,7 +613,7 @@ uint64_t ast_format_cap_to_old_bitfield(const struct ast_format_cap *cap)
 	struct ao2_iterator it;
 	struct ast_format *tmp;
 
-	it = ao2_iterator_init(cap->formats, cap->nolock ? AO2_ITERATOR_DONTLOCK : 0);
+	it = ao2_iterator_init(cap->formats, 0);
 	while ((tmp = ao2_iterator_next(&it))) {
 		res |= ast_format_to_old_bitfield(tmp);
 		ao2_ref(tmp, -1);