cregit-Linux how code gets into the kernel

Release 4.7 drivers/char/hw_random/virtio-rng.c

Directory: drivers/char/hw_random
/*
 * Randomness driver for virtio
 *  Copyright (C) 2007, 2008 Rusty Russell IBM Corporation
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <linux/err.h>
#include <linux/hw_random.h>
#include <linux/scatterlist.h>
#include <linux/spinlock.h>
#include <linux/virtio.h>
#include <linux/virtio_rng.h>
#include <linux/module.h>

static DEFINE_IDA(rng_index_ida);


struct virtrng_info {
	
struct hwrng hwrng;
	
struct virtqueue *vq;
	
struct completion have_data;
	
char name[25];
	
unsigned int data_avail;
	
int index;
	
bool busy;
	
bool hwrng_register_done;
	
bool hwrng_removed;
};




static void random_recv_done(struct virtqueue *vq)
{
	struct virtrng_info *vi = vq->vdev->priv;

	/* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */
	if (!virtqueue_get_buf(vi->vq, &vi->data_avail))
		return;

	complete(&vi->have_data);
}


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rusty russellrusty russell2655.32%120.00%


amos kongamos kong1736.17%120.00%


christian borntraegerchristian borntraeger24.26%120.00%


michael s. tsirkinmichael s. tsirkin12.13%120.00%


ian moltonian molton12.13%120.00%


Total47100.00%5100.00%



/* The host will fill any buffer we give it with sweet, sweet randomness. */



static void register_buffer(struct virtrng_info *vi, u8 *buf, size_t size)
{
	struct scatterlist sg;

	sg_init_one(&sg, buf, size);

	/* There should always be room for one buffer. */
	virtqueue_add_inbuf(vi->vq, &sg, 1, buf, GFP_KERNEL);

	virtqueue_kick(vi->vq);
}


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rusty russellrusty russell3766.07%350.00%


ian moltonian molton916.07%116.67%


amos kongamos kong916.07%116.67%


michael s. tsirkinmichael s. tsirkin11.79%116.67%


Total56100.00%6100.00%






static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait)
{
	int ret;
	struct virtrng_info *vi = (struct virtrng_info *)rng->priv;

	if (vi->hwrng_removed)
		return -ENODEV;

	if (!vi->busy) {
		vi->busy = true;
		init_completion(&vi->have_data);
		register_buffer(vi, buf, size);
	}

	if (!wait)
		return 0;

	ret = wait_for_completion_killable(&vi->have_data);
	if (ret < 0)
		return ret;

	vi->busy = false;

	return vi->data_avail;
}


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amos kongamos kong3832.20%233.33%


ian moltonian molton3327.97%116.67%


rusty russellrusty russell3227.12%233.33%


amit shahamit shah1512.71%116.67%


Total118100.00%6100.00%






static void virtio_cleanup(struct hwrng *rng)
{
	struct virtrng_info *vi = (struct virtrng_info *)rng->priv;

	if (vi->busy)
		wait_for_completion(&vi->have_data);
}


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amos kongamos kong1846.15%133.33%


rusty russellrusty russell1743.59%133.33%


ian moltonian molton410.26%133.33%


Total39100.00%3100.00%






static int probe_common(struct virtio_device *vdev)
{
	int err, index;
	struct virtrng_info *vi = NULL;

	vi = kzalloc(sizeof(struct virtrng_info), GFP_KERNEL);
	if (!vi)
		return -ENOMEM;

	vi->index = index = ida_simple_get(&rng_index_ida, 0, 0, GFP_KERNEL);
	if (index < 0) {
		err = index;
		goto err_ida;
	}
	sprintf(vi->name, "virtio_rng.%d", index);
	init_completion(&vi->have_data);

	vi->hwrng = (struct hwrng) {
		.read = virtio_read,
		.cleanup = virtio_cleanup,
		.priv = (unsigned long)vi,
		.name = vi->name,
		.quality = 1000,
        };
	vdev->priv = vi;

	/* We expect a single virtqueue. */
	vi->vq = virtio_find_single_vq(vdev, random_recv_done, "input");
	if (IS_ERR(vi->vq)) {
		err = PTR_ERR(vi->vq);
		goto err_find;
	}

	return 0;

err_find:
	ida_simple_remove(&rng_index_ida, index);
err_ida:
	kfree(vi);
	return err;
}


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amos kongamos kong6933.82%110.00%


sasha levinsasha levin6431.37%220.00%


rusty russellrusty russell3517.16%220.00%


michael s. tsirkinmichael s. tsirkin2311.27%220.00%


amit shahamit shah136.37%330.00%


Total204100.00%10100.00%






static void remove_common(struct virtio_device *vdev)
{
	struct virtrng_info *vi = vdev->priv;

	vi->hwrng_removed = true;
	vi->data_avail = 0;
	complete(&vi->have_data);
	vdev->config->reset(vdev);
	vi->busy = false;
	if (vi->hwrng_register_done)
		hwrng_unregister(&vi->hwrng);
	vdev->config->del_vqs(vdev);
	ida_simple_remove(&rng_index_ida, vi->index);
	kfree(vi);
}


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amos kongamos kong4447.31%333.33%


rusty russellrusty russell2830.11%111.11%


amit shahamit shah1415.05%333.33%


sasha levinsasha levin55.38%111.11%


michael s. tsirkinmichael s. tsirkin22.15%111.11%


Total93100.00%9100.00%






static int virtrng_probe(struct virtio_device *vdev)
{
	return probe_common(vdev);
}


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amit shahamit shah17100.00%1100.00%


Total17100.00%1100.00%






static void virtrng_remove(struct virtio_device *vdev)
{
	remove_common(vdev);
}


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amit shahamit shah1381.25%150.00%


rusty russellrusty russell318.75%150.00%


Total16100.00%2100.00%






static void virtrng_scan(struct virtio_device *vdev)
{
	struct virtrng_info *vi = vdev->priv;
	int err;

	err = hwrng_register(&vi->hwrng);
	if (!err)
		vi->hwrng_register_done = true;
}


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amit shahamit shah44100.00%1100.00%


Total44100.00%1100.00%



#ifdef CONFIG_PM_SLEEP



static int virtrng_freeze(struct virtio_device *vdev)
{
	remove_common(vdev);
	return 0;
}


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amit shahamit shah19100.00%1100.00%


Total19100.00%1100.00%






static int virtrng_restore(struct virtio_device *vdev)
{
	return probe_common(vdev);
}

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amit shahamit shah17100.00%1100.00%


Total17100.00%1100.00%



#endif


static struct virtio_device_id id_table[] = {
	{ VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID },
	{ 0 },
};


static struct virtio_driver virtio_rng_driver = {
	.driver.name =	KBUILD_MODNAME,
	.driver.owner =	THIS_MODULE,
	.id_table =	id_table,
	.probe =	virtrng_probe,
	.remove =	virtrng_remove,
	.scan =		virtrng_scan,
#ifdef CONFIG_PM_SLEEP
	.freeze =	virtrng_freeze,
	.restore =	virtrng_restore,
#endif
};


module_virtio_driver(virtio_rng_driver);
MODULE_DEVICE_TABLE(virtio, id_table);
MODULE_DESCRIPTION("Virtio random number driver");
MODULE_LICENSE("GPL");

Overall Contributors
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rusty russellrusty russell27732.94%622.22%


amos kongamos kong21024.97%311.11%


amit shahamit shah18722.24%829.63%


sasha levinsasha levin849.99%27.41%


ian moltonian molton485.71%13.70%


michael s. tsirkinmichael s. tsirkin273.21%311.11%


paul gortmakerpaul gortmaker30.36%13.70%


aaron luaaron lu20.24%13.70%


christian borntraegerchristian borntraeger20.24%13.70%


jeff mahoneyjeff mahoney10.12%13.70%


Total841100.00%27100.00%

  
Directory: drivers/char/hw_random



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