diff options
Diffstat (limited to 'drivers/xen/xenbus/xenbus_dev_frontend.c')
-rw-r--r-- | drivers/xen/xenbus/xenbus_dev_frontend.c | 188 |
1 files changed, 120 insertions, 68 deletions
diff --git a/drivers/xen/xenbus/xenbus_dev_frontend.c b/drivers/xen/xenbus/xenbus_dev_frontend.c index e4b984777507..4d343eed08f5 100644 --- a/drivers/xen/xenbus/xenbus_dev_frontend.c +++ b/drivers/xen/xenbus/xenbus_dev_frontend.c @@ -113,6 +113,7 @@ struct xenbus_file_priv { struct list_head read_buffers; wait_queue_head_t read_waitq; + struct kref kref; }; /* Read out any raw xenbus messages queued up. */ @@ -297,6 +298,107 @@ static void watch_fired(struct xenbus_watch *watch, mutex_unlock(&adap->dev_data->reply_mutex); } +static void xenbus_file_free(struct kref *kref) +{ + struct xenbus_file_priv *u; + struct xenbus_transaction_holder *trans, *tmp; + struct watch_adapter *watch, *tmp_watch; + struct read_buffer *rb, *tmp_rb; + + u = container_of(kref, struct xenbus_file_priv, kref); + + /* + * No need for locking here because there are no other users, + * by definition. + */ + + list_for_each_entry_safe(trans, tmp, &u->transactions, list) { + xenbus_transaction_end(trans->handle, 1); + list_del(&trans->list); + kfree(trans); + } + + list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { + unregister_xenbus_watch(&watch->watch); + list_del(&watch->list); + free_watch_adapter(watch); + } + + list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) { + list_del(&rb->list); + kfree(rb); + } + kfree(u); +} + +static struct xenbus_transaction_holder *xenbus_get_transaction( + struct xenbus_file_priv *u, uint32_t tx_id) +{ + struct xenbus_transaction_holder *trans; + + list_for_each_entry(trans, &u->transactions, list) + if (trans->handle.id == tx_id) + return trans; + + return NULL; +} + +void xenbus_dev_queue_reply(struct xb_req_data *req) +{ + struct xenbus_file_priv *u = req->par; + struct xenbus_transaction_holder *trans = NULL; + int rc; + LIST_HEAD(staging_q); + + xs_request_exit(req); + + mutex_lock(&u->msgbuffer_mutex); + + if (req->type == XS_TRANSACTION_START) { + trans = xenbus_get_transaction(u, 0); + if (WARN_ON(!trans)) + goto out; + if (req->msg.type == XS_ERROR) { + list_del(&trans->list); + kfree(trans); + } else { + rc = kstrtou32(req->body, 10, &trans->handle.id); + if (WARN_ON(rc)) + goto out; + } + } else if (req->msg.type == XS_TRANSACTION_END) { + trans = xenbus_get_transaction(u, req->msg.tx_id); + if (WARN_ON(!trans)) + goto out; + list_del(&trans->list); + kfree(trans); + } + + mutex_unlock(&u->msgbuffer_mutex); + + mutex_lock(&u->reply_mutex); + rc = queue_reply(&staging_q, &req->msg, sizeof(req->msg)); + if (!rc) + rc = queue_reply(&staging_q, req->body, req->msg.len); + if (!rc) { + list_splice_tail(&staging_q, &u->read_buffers); + wake_up(&u->read_waitq); + } else { + queue_cleanup(&staging_q); + } + mutex_unlock(&u->reply_mutex); + + kfree(req->body); + kfree(req); + + kref_put(&u->kref, xenbus_file_free); + + return; + + out: + mutex_unlock(&u->msgbuffer_mutex); +} + static int xenbus_command_reply(struct xenbus_file_priv *u, unsigned int msg_type, const char *reply) { @@ -317,6 +419,9 @@ static int xenbus_command_reply(struct xenbus_file_priv *u, wake_up(&u->read_waitq); mutex_unlock(&u->reply_mutex); + if (!rc) + kref_put(&u->kref, xenbus_file_free); + return rc; } @@ -324,57 +429,22 @@ static int xenbus_write_transaction(unsigned msg_type, struct xenbus_file_priv *u) { int rc; - void *reply; struct xenbus_transaction_holder *trans = NULL; - LIST_HEAD(staging_q); if (msg_type == XS_TRANSACTION_START) { - trans = kmalloc(sizeof(*trans), GFP_KERNEL); + trans = kzalloc(sizeof(*trans), GFP_KERNEL); if (!trans) { rc = -ENOMEM; goto out; } - } else if (u->u.msg.tx_id != 0) { - list_for_each_entry(trans, &u->transactions, list) - if (trans->handle.id == u->u.msg.tx_id) - break; - if (&trans->list == &u->transactions) - return xenbus_command_reply(u, XS_ERROR, "ENOENT"); - } - - reply = xenbus_dev_request_and_reply(&u->u.msg); - if (IS_ERR(reply)) { - if (msg_type == XS_TRANSACTION_START) - kfree(trans); - rc = PTR_ERR(reply); - goto out; - } + list_add(&trans->list, &u->transactions); + } else if (u->u.msg.tx_id != 0 && + !xenbus_get_transaction(u, u->u.msg.tx_id)) + return xenbus_command_reply(u, XS_ERROR, "ENOENT"); - if (msg_type == XS_TRANSACTION_START) { - if (u->u.msg.type == XS_ERROR) - kfree(trans); - else { - trans->handle.id = simple_strtoul(reply, NULL, 0); - list_add(&trans->list, &u->transactions); - } - } else if (u->u.msg.type == XS_TRANSACTION_END) { - list_del(&trans->list); + rc = xenbus_dev_request_and_reply(&u->u.msg, u); + if (rc) kfree(trans); - } - - mutex_lock(&u->reply_mutex); - rc = queue_reply(&staging_q, &u->u.msg, sizeof(u->u.msg)); - if (!rc) - rc = queue_reply(&staging_q, reply, u->u.msg.len); - if (!rc) { - list_splice_tail(&staging_q, &u->read_buffers); - wake_up(&u->read_waitq); - } else { - queue_cleanup(&staging_q); - } - mutex_unlock(&u->reply_mutex); - - kfree(reply); out: return rc; @@ -506,6 +576,8 @@ static ssize_t xenbus_file_write(struct file *filp, * OK, now we have a complete message. Do something with it. */ + kref_get(&u->kref); + msg_type = u->u.msg.type; switch (msg_type) { @@ -520,8 +592,10 @@ static ssize_t xenbus_file_write(struct file *filp, ret = xenbus_write_transaction(msg_type, u); break; } - if (ret != 0) + if (ret != 0) { rc = ret; + kref_put(&u->kref, xenbus_file_free); + } /* Buffered message consumed */ u->len = 0; @@ -546,6 +620,8 @@ static int xenbus_file_open(struct inode *inode, struct file *filp) if (u == NULL) return -ENOMEM; + kref_init(&u->kref); + INIT_LIST_HEAD(&u->transactions); INIT_LIST_HEAD(&u->watches); INIT_LIST_HEAD(&u->read_buffers); @@ -562,32 +638,8 @@ static int xenbus_file_open(struct inode *inode, struct file *filp) static int xenbus_file_release(struct inode *inode, struct file *filp) { struct xenbus_file_priv *u = filp->private_data; - struct xenbus_transaction_holder *trans, *tmp; - struct watch_adapter *watch, *tmp_watch; - struct read_buffer *rb, *tmp_rb; - - /* - * No need for locking here because there are no other users, - * by definition. - */ - list_for_each_entry_safe(trans, tmp, &u->transactions, list) { - xenbus_transaction_end(trans->handle, 1); - list_del(&trans->list); - kfree(trans); - } - - list_for_each_entry_safe(watch, tmp_watch, &u->watches, list) { - unregister_xenbus_watch(&watch->watch); - list_del(&watch->list); - free_watch_adapter(watch); - } - - list_for_each_entry_safe(rb, tmp_rb, &u->read_buffers, list) { - list_del(&rb->list); - kfree(rb); - } - kfree(u); + kref_put(&u->kref, xenbus_file_free); return 0; } |