Re: [PATCH 2/2] virtio: Use ida to allocate virtio index
flat view
From: Rusty Russell <hidden>
Date: 2012-05-07 04:57:23
Also in:
kvm
On Thu, 3 May 2012 10:20:51 +0800, Asias He [off-list ref] wrote:
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 <redacted>Applied. Nice and simple. Thanks, Rusty.
quoted hunk ↗ jump to hunk
--- 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 <linux/spinlock.h> #include <linux/virtio_config.h> #include <linux/module.h> +#include <linux/idr.h> /* 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