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Commit 90e03207 authored by Asias He's avatar Asias He Committed by Rusty Russell
Browse files

virtio: Use ida to allocate virtio index 



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: default avatarAsias He <asias@redhat.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent c877bab5

drivers/virtio/virtio.c

+9 −2
Original line number Diff line number Diff line
@@ -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);