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/* Management for virtio crypto devices (refer to adf_dev_mgr.c)
*
* Copyright 2016 HUAWEI TECHNOLOGIES CO., LTD.
*
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <linux/mutex.h>
#include <linux/list.h>
#include <linux/module.h>
#include <uapi/linux/virtio_crypto.h>
#include "virtio_crypto_common.h"
static LIST_HEAD(virtio_crypto_table);
static uint32_t num_devices;
/* The table_lock protects the above global list and num_devices */
static DEFINE_MUTEX(table_lock);
#define VIRTIO_CRYPTO_MAX_DEVICES 32
/*
* virtcrypto_devmgr_add_dev() - Add vcrypto_dev to the acceleration
* framework.
* @vcrypto_dev: Pointer to virtio crypto device.
*
* Function adds virtio crypto device to the global list.
* To be used by virtio crypto device specific drivers.
*
* Return: 0 on success, error code othewise.
*/
int virtcrypto_devmgr_add_dev(struct virtio_crypto *vcrypto_dev)
{
struct list_head *itr;
mutex_lock(&table_lock);
if (num_devices == VIRTIO_CRYPTO_MAX_DEVICES) {
pr_info("virtio_crypto: only support up to %d devices\n",
VIRTIO_CRYPTO_MAX_DEVICES);
mutex_unlock(&table_lock);
return -EFAULT;
}
list_for_each(itr, &virtio_crypto_table) {
struct virtio_crypto *ptr =
list_entry(itr, struct virtio_crypto, list);
if (ptr == vcrypto_dev) {
mutex_unlock(&table_lock);
return -EEXIST;
}
}
atomic_set(&vcrypto_dev->ref_count, 0);
list_add_tail(&vcrypto_dev->list, &virtio_crypto_table);
vcrypto_dev->dev_id = num_devices++;
mutex_unlock(&table_lock);
return 0;
}
struct list_head *virtcrypto_devmgr_get_head(void)
{
return &virtio_crypto_table;
}
/*
* virtcrypto_devmgr_rm_dev() - Remove vcrypto_dev from the acceleration
* framework.
* @vcrypto_dev: Pointer to virtio crypto device.
*
* Function removes virtio crypto device from the acceleration framework.
* To be used by virtio crypto device specific drivers.
*
* Return: void
*/
void virtcrypto_devmgr_rm_dev(struct virtio_crypto *vcrypto_dev)
{
mutex_lock(&table_lock);
list_del(&vcrypto_dev->list);
num_devices--;
mutex_unlock(&table_lock);
}
/*
* virtcrypto_devmgr_get_first()
*
* Function returns the first virtio crypto device from the acceleration
* framework.
*
* To be used by virtio crypto device specific drivers.
*
* Return: pointer to vcrypto_dev or NULL if not found.
*/
struct virtio_crypto *virtcrypto_devmgr_get_first(void)
{
struct virtio_crypto *dev = NULL;
mutex_lock(&table_lock);
if (!list_empty(&virtio_crypto_table))
dev = list_first_entry(&virtio_crypto_table,
struct virtio_crypto,
list);
mutex_unlock(&table_lock);
return dev;
}
/*
* virtcrypto_dev_in_use() - Check whether vcrypto_dev is currently in use
* @vcrypto_dev: Pointer to virtio crypto device.
*
* To be used by virtio crypto device specific drivers.
*
* Return: 1 when device is in use, 0 otherwise.
*/
int virtcrypto_dev_in_use(struct virtio_crypto *vcrypto_dev)
{
return atomic_read(&vcrypto_dev->ref_count) != 0;
}
/*
* virtcrypto_dev_get() - Increment vcrypto_dev reference count
* @vcrypto_dev: Pointer to virtio crypto device.
*
* Increment the vcrypto_dev refcount and if this is the first time
* incrementing it during this period the vcrypto_dev is in use,
* increment the module refcount too.
* To be used by virtio crypto device specific drivers.
*
* Return: 0 when successful, EFAULT when fail to bump module refcount
*/
int virtcrypto_dev_get(struct virtio_crypto *vcrypto_dev)
{
if (atomic_add_return(1, &vcrypto_dev->ref_count) == 1)
if (!try_module_get(vcrypto_dev->owner))
return -EFAULT;
return 0;
}
/*
* virtcrypto_dev_put() - Decrement vcrypto_dev reference count
* @vcrypto_dev: Pointer to virtio crypto device.
*
* Decrement the vcrypto_dev refcount and if this is the last time
* decrementing it during this period the vcrypto_dev is in use,
* decrement the module refcount too.
* To be used by virtio crypto device specific drivers.
*
* Return: void
*/
void virtcrypto_dev_put(struct virtio_crypto *vcrypto_dev)
{
if (atomic_sub_return(1, &vcrypto_dev->ref_count) == 0)
module_put(vcrypto_dev->owner);
}
/*
* virtcrypto_dev_started() - Check whether device has started
* @vcrypto_dev: Pointer to virtio crypto device.
*
* To be used by virtio crypto device specific drivers.
*
* Return: 1 when the device has started, 0 otherwise
*/
int virtcrypto_dev_started(struct virtio_crypto *vcrypto_dev)
{
return (vcrypto_dev->status & VIRTIO_CRYPTO_S_HW_READY);
}
/*
* virtcrypto_get_dev_node() - Get vcrypto_dev on the node.
* @node: Node id the driver works.
*
* Function returns the virtio crypto device used fewest on the node.
*
* To be used by virtio crypto device specific drivers.
*
* Return: pointer to vcrypto_dev or NULL if not found.
*/
struct virtio_crypto *virtcrypto_get_dev_node(int node)
{
struct virtio_crypto *vcrypto_dev = NULL, *tmp_dev;
unsigned long best = ~0;
unsigned long ctr;
mutex_lock(&table_lock);
list_for_each_entry(tmp_dev, virtcrypto_devmgr_get_head(), list) {
if ((node == dev_to_node(&tmp_dev->vdev->dev) ||
dev_to_node(&tmp_dev->vdev->dev) < 0) &&
virtcrypto_dev_started(tmp_dev)) {
ctr = atomic_read(&tmp_dev->ref_count);
if (best > ctr) {
vcrypto_dev = tmp_dev;
best = ctr;
}
}
}
if (!vcrypto_dev) {
pr_info("virtio_crypto: Could not find a device on node %d\n",
node);
/* Get any started device */
list_for_each_entry(tmp_dev,
virtcrypto_devmgr_get_head(), list) {
if (virtcrypto_dev_started(tmp_dev)) {
vcrypto_dev = tmp_dev;
break;
}
}
}
mutex_unlock(&table_lock);
if (!vcrypto_dev)
return NULL;
virtcrypto_dev_get(vcrypto_dev);
return vcrypto_dev;
}
/*
* virtcrypto_dev_start() - Start virtio crypto device
* @vcrypto: Pointer to virtio crypto device.
*
* Function notifies all the registered services that the virtio crypto device
* is ready to be used.
* To be used by virtio crypto device specific drivers.
*
* Return: 0 on success, EFAULT when fail to register algorithms
*/
int virtcrypto_dev_start(struct virtio_crypto *vcrypto)
{
if (virtio_crypto_algs_register()) {
pr_err("virtio_crypto: Failed to register crypto algs\n");
return -EFAULT;
}
return 0;
}
/*
* virtcrypto_dev_stop() - Stop virtio crypto device
* @vcrypto: Pointer to virtio crypto device.
*
* Function notifies all the registered services that the virtio crypto device
* is ready to be used.
* To be used by virtio crypto device specific drivers.
*
* Return: void
*/
void virtcrypto_dev_stop(struct virtio_crypto *vcrypto)
{
virtio_crypto_algs_unregister();
}
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