Re: [PATCH] crypto: virtio-crypto: Handle dataq logic with tasklet

["Michael S. Tsirkin" <mst@redhat.com>]

On Mon, Nov 20, 2023 at 11:49:45AM +0000, Gonglei (Arei) wrote:
> Doing ipsec produces a spinlock recursion warning.
> This is due to crypto_finalize_request() being called in the upper half.
> Move virtual data queue processing of virtio-crypto driver to tasklet.
> 
> Fixes: dbaf0624ffa57 ("crypto: add virtio-crypto driver")
> Reported-by: Halil Pasic <pasic@linux.ibm.com>
> Signed-off-by: wangyangxin <wangyangxin1@huawei.com>
> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
> ---
>  drivers/crypto/virtio/virtio_crypto_common.h |  2 ++
>  drivers/crypto/virtio/virtio_crypto_core.c   | 23 +++++++++++++----------
>  2 files changed, 15 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/crypto/virtio/virtio_crypto_common.h b/drivers/crypto/virtio/virtio_crypto_common.h
> index 59a4c02..5c17c6e 100644
> --- a/drivers/crypto/virtio/virtio_crypto_common.h
> +++ b/drivers/crypto/virtio/virtio_crypto_common.h
> @@ -10,6 +10,7 @@
>  #include <linux/virtio.h>
>  #include <linux/crypto.h>
>  #include <linux/spinlock.h>
> +#include <linux/interrupt.h>
>  #include <crypto/aead.h>
>  #include <crypto/aes.h>
>  #include <crypto/engine.h>
> @@ -28,6 +29,7 @@ struct data_queue {
>  	char name[32];
>  
>  	struct crypto_engine *engine;
> +	struct tasklet_struct done_task;
>  };
>  
>  struct virtio_crypto {
> diff --git a/drivers/crypto/virtio/virtio_crypto_core.c b/drivers/crypto/virtio/virtio_crypto_core.c
> index 1198bd3..e747f4f 100644
> --- a/drivers/crypto/virtio/virtio_crypto_core.c
> +++ b/drivers/crypto/virtio/virtio_crypto_core.c
> @@ -72,27 +72,28 @@ int virtio_crypto_ctrl_vq_request(struct virtio_crypto *vcrypto, struct scatterl
>  	return 0;
>  }
>  
> -static void virtcrypto_dataq_callback(struct virtqueue *vq)
> +static void virtcrypto_done_task(unsigned long data)
>  {
> -	struct virtio_crypto *vcrypto = vq->vdev->priv;
> +	struct data_queue *data_vq = (struct data_queue *)data;
> +	struct virtqueue *vq = data_vq->vq;
>  	struct virtio_crypto_request *vc_req;
> -	unsigned long flags;
>  	unsigned int len;
> -	unsigned int qid = vq->index;
>  
> -	spin_lock_irqsave(&vcrypto->data_vq[qid].lock, flags);
>  	do {
>  		virtqueue_disable_cb(vq);
>  		while ((vc_req = virtqueue_get_buf(vq, &len)) != NULL) {
> -			spin_unlock_irqrestore(
> -				&vcrypto->data_vq[qid].lock, flags);
>  			if (vc_req->alg_cb)
>  				vc_req->alg_cb(vc_req, len);
> -			spin_lock_irqsave(
> -				&vcrypto->data_vq[qid].lock, flags);
>  		}
>  	} while (!virtqueue_enable_cb(vq));
> -	spin_unlock_irqrestore(&vcrypto->data_vq[qid].lock, flags);
> +}
> +
> +static void virtcrypto_dataq_callback(struct virtqueue *vq)
> +{
> +	struct virtio_crypto *vcrypto = vq->vdev->priv;
> +	struct data_queue *dq = &vcrypto->data_vq[vq->index];
> +
> +	tasklet_schedule(&dq->done_task);
>  }
>

Don't we then need to wait for tasklet to complete on
device remove?

  
>  static int virtcrypto_find_vqs(struct virtio_crypto *vi)
> @@ -150,6 +151,8 @@ static int virtcrypto_find_vqs(struct virtio_crypto *vi)
>  			ret = -ENOMEM;
>  			goto err_engine;
>  		}
> +		tasklet_init(&vi->data_vq[i].done_task, virtcrypto_done_task,
> +				(unsigned long)&vi->data_vq[i]);
>  	}
>  
>  	kfree(names);
> -- 
> 1.8.3.1
> 
>