From mboxrd@z Thu Jan 1 00:00:00 1970 From: Asias He Subject: [PATCH 2/2] virtio: Use ida to allocate virtio index Date: Thu, 3 May 2012 10:20:51 +0800 Message-ID: <1336011651-24997-1-git-send-email-asias@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: virtualization@lists.linux-foundation.org, Rusty Russell , "Michael S. Tsirkin" Cc: kvm@vger.kernel.org List-Id: virtualization@lists.linuxfoundation.org Current index allocation in virtio is based on a monotonically increasing variable "index". This means we'll run out of numbers after a while. E.g. someone crazy doing this in host side. while(1) { hot-plug a virtio device hot-unplug the virito devcie } Signed-off-by: Asias He --- drivers/virtio/virtio.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c index 984c501..f355807 100644 --- a/drivers/virtio/virtio.c +++ b/drivers/virtio/virtio.c @@ -2,9 +2,10 @@ #include #include #include +#include /* Unique numbering for virtio devices. */ -static unsigned int dev_index; +static DEFINE_IDA(virtio_index_ida); static ssize_t device_show(struct device *_d, struct device_attribute *attr, char *buf) @@ -193,7 +194,11 @@ int register_virtio_device(struct virtio_device *dev) dev->dev.bus = &virtio_bus; /* Assign a unique device index and hence name. */ - dev->index = dev_index++; + err = ida_simple_get(&virtio_index_ida, 0, 0, GFP_KERNEL); + if (err < 0) + goto out; + + dev->index = err; dev_set_name(&dev->dev, "virtio%u", dev->index); /* We always start by resetting the device, in case a previous @@ -208,6 +213,7 @@ int register_virtio_device(struct virtio_device *dev) /* device_register() causes the bus infrastructure to look for a * matching driver. */ err = device_register(&dev->dev); +out: if (err) add_status(dev, VIRTIO_CONFIG_S_FAILED); return err; @@ -217,6 +223,7 @@ EXPORT_SYMBOL_GPL(register_virtio_device); void unregister_virtio_device(struct virtio_device *dev) { device_unregister(&dev->dev); + ida_simple_remove(&virtio_index_ida, dev->index); } EXPORT_SYMBOL_GPL(unregister_virtio_device); -- 1.7.10