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-rw-r--r--sound/core/seq/seq_ports.c39
1 files changed, 27 insertions, 12 deletions
diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c
index b9c2ce2b8d5a..84d78630463e 100644
--- a/sound/core/seq/seq_ports.c
+++ b/sound/core/seq/seq_ports.c
@@ -514,10 +514,11 @@ static int check_and_subscribe_port(struct snd_seq_client *client,
return err;
}
-static void delete_and_unsubscribe_port(struct snd_seq_client *client,
- struct snd_seq_client_port *port,
- struct snd_seq_subscribers *subs,
- bool is_src, bool ack)
+/* called with grp->list_mutex held */
+static void __delete_and_unsubscribe_port(struct snd_seq_client *client,
+ struct snd_seq_client_port *port,
+ struct snd_seq_subscribers *subs,
+ bool is_src, bool ack)
{
struct snd_seq_port_subs_info *grp;
struct list_head *list;
@@ -525,7 +526,6 @@ static void delete_and_unsubscribe_port(struct snd_seq_client *client,
grp = is_src ? &port->c_src : &port->c_dest;
list = is_src ? &subs->src_list : &subs->dest_list;
- down_write(&grp->list_mutex);
write_lock_irq(&grp->list_lock);
empty = list_empty(list);
if (!empty)
@@ -535,6 +535,18 @@ static void delete_and_unsubscribe_port(struct snd_seq_client *client,
if (!empty)
unsubscribe_port(client, port, grp, &subs->info, ack);
+}
+
+static void delete_and_unsubscribe_port(struct snd_seq_client *client,
+ struct snd_seq_client_port *port,
+ struct snd_seq_subscribers *subs,
+ bool is_src, bool ack)
+{
+ struct snd_seq_port_subs_info *grp;
+
+ grp = is_src ? &port->c_src : &port->c_dest;
+ down_write(&grp->list_mutex);
+ __delete_and_unsubscribe_port(client, port, subs, is_src, ack);
up_write(&grp->list_mutex);
}
@@ -590,27 +602,30 @@ int snd_seq_port_disconnect(struct snd_seq_client *connector,
struct snd_seq_client_port *dest_port,
struct snd_seq_port_subscribe *info)
{
- struct snd_seq_port_subs_info *src = &src_port->c_src;
+ struct snd_seq_port_subs_info *dest = &dest_port->c_dest;
struct snd_seq_subscribers *subs;
int err = -ENOENT;
- down_write(&src->list_mutex);
+ /* always start from deleting the dest port for avoiding concurrent
+ * deletions
+ */
+ down_write(&dest->list_mutex);
/* look for the connection */
- list_for_each_entry(subs, &src->list_head, src_list) {
+ list_for_each_entry(subs, &dest->list_head, dest_list) {
if (match_subs_info(info, &subs->info)) {
- atomic_dec(&subs->ref_count); /* mark as not ready */
+ __delete_and_unsubscribe_port(dest_client, dest_port,
+ subs, false,
+ connector->number != dest_client->number);
err = 0;
break;
}
}
- up_write(&src->list_mutex);
+ up_write(&dest->list_mutex);
if (err < 0)
return err;
delete_and_unsubscribe_port(src_client, src_port, subs, true,
connector->number != src_client->number);
- delete_and_unsubscribe_port(dest_client, dest_port, subs, false,
- connector->number != dest_client->number);
kfree(subs);
return 0;
}