[dpdk-dev] [PATCH v3] bus/vdev: replace device list lock by a recursive one

[Matan Azrad]

From: Thomas Monjalon
> A device like failsafe can manage sub-devices.
> When removing such device, it removes its sub-devices and try to take the
> same vdev_device_list_lock.
> It was causing a deadlock because the lock was not recursive.
> 
> Fixes: 35f462839b69 ("bus/vdev: add lock on device list")
> 
> Suggested-by: Anatoly Burakov <anatoly.burakov at intel.com>
> Signed-off-by: Thomas Monjalon <thomas at monjalon.net>
Tested-by: Matan Azrad <matan at mellanox.com>
> ---
> v3: try recursive lock
> WARNING: not yet tested!
> ---
>  drivers/bus/vdev/vdev.c | 26 ++++++++++++++------------
>  1 file changed, 14 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c index
> 099b9ff85..6139dd551 100644
> --- a/drivers/bus/vdev/vdev.c
> +++ b/drivers/bus/vdev/vdev.c
> @@ -36,7 +36,9 @@ TAILQ_HEAD(vdev_device_list, rte_vdev_device);
> 
>  static struct vdev_device_list vdev_device_list =
>  	TAILQ_HEAD_INITIALIZER(vdev_device_list);
> -static rte_spinlock_t vdev_device_list_lock = RTE_SPINLOCK_INITIALIZER;
> +/* The lock needs to be recursive because a vdev can manage another
> +vdev. */ static rte_spinlock_recursive_t vdev_device_list_lock =
> +	RTE_SPINLOCK_RECURSIVE_INITIALIZER;
> 
>  struct vdev_driver_list vdev_driver_list =
>  	TAILQ_HEAD_INITIALIZER(vdev_driver_list);
> @@ -249,7 +251,7 @@ rte_vdev_init(const char *name, const char *args)
>  	struct rte_devargs *devargs;
>  	int ret;
> 
> -	rte_spinlock_lock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_lock(&vdev_device_list_lock);
>  	ret = insert_vdev(name, args, &dev);
>  	if (ret == 0) {
>  		ret = vdev_probe_all_drivers(dev);
> @@ -263,7 +265,7 @@ rte_vdev_init(const char *name, const char *args)
>  			free(dev);
>  		}
>  	}
> -	rte_spinlock_unlock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>  	return ret;
>  }
> 
> @@ -293,7 +295,7 @@ rte_vdev_uninit(const char *name)
>  	if (name == NULL)
>  		return -EINVAL;
> 
> -	rte_spinlock_lock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_lock(&vdev_device_list_lock);
> 
>  	dev = find_vdev(name);
>  	if (!dev) {
> @@ -311,7 +313,7 @@ rte_vdev_uninit(const char *name)
>  	free(dev);
> 
>  unlock:
> -	rte_spinlock_unlock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>  	return ret;
>  }
> 
> @@ -355,7 +357,7 @@ vdev_action(const struct rte_mp_msg *mp_msg, const
> void *peer)
>  		ou->num = 1;
>  		num = 0;
> 
> -		rte_spinlock_lock(&vdev_device_list_lock);
> +		rte_spinlock_recursive_lock(&vdev_device_list_lock);
>  		TAILQ_FOREACH(dev, &vdev_device_list, next) {
>  			devname = rte_vdev_device_name(dev);
>  			if (strlen(devname) == 0) {
> @@ -369,7 +371,7 @@ vdev_action(const struct rte_mp_msg *mp_msg, const
> void *peer)
>  					 devname, strerror(rte_errno));
>  			num++;
>  		}
> -		rte_spinlock_unlock(&vdev_device_list_lock);
> +		rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> 
>  		ou->type = VDEV_SCAN_REP;
>  		ou->num = num;
> @@ -445,10 +447,10 @@ vdev_scan(void)
>  		if (!dev)
>  			return -1;
> 
> -		rte_spinlock_lock(&vdev_device_list_lock);
> +		rte_spinlock_recursive_lock(&vdev_device_list_lock);
> 
>  		if (find_vdev(devargs->name)) {
> -			rte_spinlock_unlock(&vdev_device_list_lock);
> +
> 	rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>  			free(dev);
>  			continue;
>  		}
> @@ -459,7 +461,7 @@ vdev_scan(void)
> 
>  		TAILQ_INSERT_TAIL(&vdev_device_list, dev, next);
> 
> -		rte_spinlock_unlock(&vdev_device_list_lock);
> +		rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>  	}
> 
>  	return 0;
> @@ -498,7 +500,7 @@ vdev_find_device(const struct rte_device *start,
> rte_dev_cmp_t cmp,
>  	const struct rte_vdev_device *vstart;
>  	struct rte_vdev_device *dev;
> 
> -	rte_spinlock_lock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_lock(&vdev_device_list_lock);
>  	if (start != NULL) {
>  		vstart = RTE_DEV_TO_VDEV_CONST(start);
>  		dev = TAILQ_NEXT(vstart, next);
> @@ -510,7 +512,7 @@ vdev_find_device(const struct rte_device *start,
> rte_dev_cmp_t cmp,
>  			break;
>  		dev = TAILQ_NEXT(dev, next);
>  	}
> -	rte_spinlock_unlock(&vdev_device_list_lock);
> +	rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> 
>  	return dev ? &dev->device : NULL;
>  }
> --
> 2.16.2