ALSA: seq: More protection for concurrent write and ioctl races

[pandora-kernel.git] / sound / core / seq / seq_clientmgr.c

diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c
index 04522dc..12f80c5 100644 (file)
--- a/sound/core/seq/seq_clientmgr.c
+++ b/sound/core/seq/seq_clientmgr.c
@@ -907,7 +907,8 @@ int snd_seq_dispatch_event(struct snd_seq_event_cell *cell, int atomic, int hop)
 static int snd_seq_client_enqueue_event(struct snd_seq_client *client,
                                        struct snd_seq_event *event,
                                        struct file *file, int blocking,
-                                       int atomic, int hop)
+                                       int atomic, int hop,
+                                       struct mutex *mutexp)
 {
        struct snd_seq_event_cell *cell;
        int err;
@@ -945,7 +946,8 @@ static int snd_seq_client_enqueue_event(struct snd_seq_client *client,
                return -ENXIO; /* queue is not allocated */
 
        /* allocate an event cell */
-       err = snd_seq_event_dup(client->pool, event, &cell, !blocking || atomic, file);
+       err = snd_seq_event_dup(client->pool, event, &cell, !blocking || atomic,
+                               file, mutexp);
        if (err < 0)
                return err;
 
@@ -1014,12 +1016,11 @@ static ssize_t snd_seq_write(struct file *file, const char __user *buf,
                return -ENXIO;
 
        /* allocate the pool now if the pool is not allocated yet */ 
+       mutex_lock(&client->ioctl_mutex);
        if (client->pool->size > 0 && !snd_seq_write_pool_allocated(client)) {
-               mutex_lock(&client->ioctl_mutex);
                err = snd_seq_pool_init(client->pool);
-               mutex_unlock(&client->ioctl_mutex);
                if (err < 0)
-                       return -ENOMEM;
+                       goto out;
        }
 
        /* only process whole events */
@@ -1070,7 +1071,7 @@ static ssize_t snd_seq_write(struct file *file, const char __user *buf,
                /* ok, enqueue it */
                err = snd_seq_client_enqueue_event(client, &event, file,
                                                   !(file->f_flags & O_NONBLOCK),
-                                                  0, 0);
+                                                  0, 0, &client->ioctl_mutex);
                if (err < 0)
                        break;
 
@@ -1081,6 +1082,8 @@ static ssize_t snd_seq_write(struct file *file, const char __user *buf,
                written += len;
        }
 
+ out:
+       mutex_unlock(&client->ioctl_mutex);
        return written ? written : err;
 }
 
@@ -2343,7 +2346,8 @@ static int kernel_client_enqueue(int client, struct snd_seq_event *ev,
        if (! cptr->accept_output)
                result = -EPERM;
        else /* send it */
-               result = snd_seq_client_enqueue_event(cptr, ev, file, blocking, atomic, hop);
+               result = snd_seq_client_enqueue_event(cptr, ev, file, blocking,
+                                                     atomic, hop, NULL);
 
        snd_seq_client_unlock(cptr);
        return result;