Commit 1bdc8555 authored by Shashank Gupta's avatar Shashank Gupta Committed by Herbert Xu
Browse files

crypto: qat - fix concurrency issue when device state changes 



The sysfs `state` attribute is not protected against race conditions.
If multiple processes perform a device state transition on the same
device in parallel, unexpected behaviors might occur.

For transitioning the device state, adf_sysfs.c calls the functions
adf_dev_init(), adf_dev_start(), adf_dev_stop() and adf_dev_shutdown()
which are unprotected and interdependent on each other. To perform a
state transition, these functions needs to be called in a specific
order:
  * device up:   adf_dev_init() -> adf_dev_start()
  * device down: adf_dev_stop() -> adf_dev_shutdown()

This change introduces the functions adf_dev_up() and adf_dev_down()
which wrap the state machine functions and protect them with a
per-device lock. These are then used in adf_sysfs.c instead of the
individual state transition functions.

Fixes: 5ee52118 ("crypto: qat - expose device state through sysfs for 4xxx")
Signed-off-by: default avatarShashank Gupta <shashank.gupta@intel.com>
Reviewed-by: default avatarGiovanni Cabiddu <giovanni.cabiddu@intel.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 59a0ab49

drivers/crypto/qat/qat_common/adf_accel_devices.h

+1 −0
Original line number Diff line number Diff line
@@ -310,6 +310,7 @@ struct adf_accel_dev { 
			u8 pf_compat_ver;

		} vf;

	};

	struct mutex state_lock; /* protect state of the device */

	bool is_vf;

	u32 accel_id;

};

drivers/crypto/qat/qat_common/adf_common_drv.h

+3 −0
Original line number Diff line number Diff line
@@ -58,6 +58,9 @@ void adf_dev_stop(struct adf_accel_dev *accel_dev); 
void adf_dev_shutdown(struct adf_accel_dev *accel_dev);

int adf_dev_shutdown_cache_cfg(struct adf_accel_dev *accel_dev);



int adf_dev_up(struct adf_accel_dev *accel_dev, bool init_config);

int adf_dev_down(struct adf_accel_dev *accel_dev, bool cache_config);



void adf_devmgr_update_class_index(struct adf_hw_device_data *hw_data);

void adf_clean_vf_map(bool);

drivers/crypto/qat/qat_common/adf_dev_mgr.c

+2 −0
Original line number Diff line number Diff line
@@ -223,6 +223,7 @@ int adf_devmgr_add_dev(struct adf_accel_dev *accel_dev, 
		map->attached = true;

		list_add_tail(&map->list, &vfs_table);

	}

	mutex_init(&accel_dev->state_lock);

unlock:

	mutex_unlock(&table_lock);

	return ret;
@@ -269,6 +270,7 @@ void adf_devmgr_rm_dev(struct adf_accel_dev *accel_dev, 
		}

	}

unlock:

	mutex_destroy(&accel_dev->state_lock);

	list_del(&accel_dev->list);

	mutex_unlock(&table_lock);

}

drivers/crypto/qat/qat_common/adf_init.c

+64 −0
Original line number Diff line number Diff line
@@ -400,3 +400,67 @@ int adf_dev_shutdown_cache_cfg(struct adf_accel_dev *accel_dev) 


	return 0;

}



int adf_dev_down(struct adf_accel_dev *accel_dev, bool reconfig)

{

	int ret = 0;



	if (!accel_dev)

		return -EINVAL;



	mutex_lock(&accel_dev->state_lock);



	if (!adf_dev_started(accel_dev)) {

		dev_info(&GET_DEV(accel_dev), "Device qat_dev%d already down\n",

			 accel_dev->accel_id);

		ret = -EINVAL;

		goto out;

	}



	if (reconfig) {

		ret = adf_dev_shutdown_cache_cfg(accel_dev);

		goto out;

	}



	adf_dev_stop(accel_dev);

	adf_dev_shutdown(accel_dev);



out:

	mutex_unlock(&accel_dev->state_lock);

	return ret;

}

EXPORT_SYMBOL_GPL(adf_dev_down);



int adf_dev_up(struct adf_accel_dev *accel_dev, bool config)

{

	int ret = 0;



	if (!accel_dev)

		return -EINVAL;



	mutex_lock(&accel_dev->state_lock);



	if (adf_dev_started(accel_dev)) {

		dev_info(&GET_DEV(accel_dev), "Device qat_dev%d already up\n",

			 accel_dev->accel_id);

		ret = -EALREADY;

		goto out;

	}



	if (config && GET_HW_DATA(accel_dev)->dev_config) {

		ret = GET_HW_DATA(accel_dev)->dev_config(accel_dev);

		if (unlikely(ret))

			goto out;

	}



	ret = adf_dev_init(accel_dev);

	if (unlikely(ret))

		goto out;



	ret = adf_dev_start(accel_dev);



out:

	mutex_unlock(&accel_dev->state_lock);

	return ret;

}

EXPORT_SYMBOL_GPL(adf_dev_up);

drivers/crypto/qat/qat_common/adf_sysfs.c

+3 −20
Original line number Diff line number Diff line
@@ -50,38 +50,21 @@ static ssize_t state_store(struct device *dev, struct device_attribute *attr, 


	switch (ret) {

	case DEV_DOWN:

		if (!adf_dev_started(accel_dev)) {

			dev_info(dev, "Device qat_dev%d already down\n",

				 accel_id);

			return -EINVAL;

		}



		dev_info(dev, "Stopping device qat_dev%d\n", accel_id);



		ret = adf_dev_shutdown_cache_cfg(accel_dev);

		ret = adf_dev_down(accel_dev, true);

		if (ret < 0)

			return -EINVAL;



		break;

	case DEV_UP:

		if (adf_dev_started(accel_dev)) {

			dev_info(dev, "Device qat_dev%d already up\n",

				 accel_id);

			return -EINVAL;

		}



		dev_info(dev, "Starting device qat_dev%d\n", accel_id);



		ret = GET_HW_DATA(accel_dev)->dev_config(accel_dev);

		if (!ret)

			ret = adf_dev_init(accel_dev);

		if (!ret)

			ret = adf_dev_start(accel_dev);



		ret = adf_dev_up(accel_dev, true);

		if (ret < 0) {

			dev_err(dev, "Failed to start device qat_dev%d\n",

				accel_id);

			adf_dev_shutdown_cache_cfg(accel_dev);

			adf_dev_down(accel_dev, true);

			return ret;

		}

		break;