The only generic interface to execute asynchronously in the BH context is tasklet; however, it's marked deprecated and has some design flaws such as the execution code accessing the tasklet item after the execution is complete which can lead to subtle use-after-free in certain usage scenarios and less-developed flush and cancel mechanisms.
To replace tasklets, BH workqueue support was recently added. A BH workqueue behaves similarly to regular workqueues except that the queued work items are executed in the BH context. Convert virtio_crypto_core.c from tasklet to BH workqueue. Semantically, this is an equivalent conversion and there shouldn't be any user-visible behavior changes. The BH workqueue implementation uses the same softirq infrastructure, and performance-critical networking conversions have shown no measurable performance impact. Signed-off-by: Pat Somaru <[email protected]> --- Hi, I'm working on converting tasklet usages to the BH WQ API. The virtio-crypto driver uses a tasklet per data queue to process completed crypto operations in BH context. This converts that tasklet to use the BH workqueue infrastructure. This patch was tested by: - Building with allmodconfig: no new warnings (compared to v6.18) - Building with allyesconfig: no new warnings (compared to v6.18) - Booting defconfig kernel via vng and running `uname -a`: Linux virtme-ng 6.18.0-virtme #1 SMP PREEMPT_DYNAMIC 0 x86_64 GNU/Linux Maintainers can apply this directly to the crypto subsystem tree or ack it for the workqueue tree to carry. drivers/crypto/virtio/virtio_crypto_common.h | 3 ++- drivers/crypto/virtio/virtio_crypto_core.c | 11 +++++------ 2 files changed, 7 insertions(+), 7 deletions(-) diff --git a/drivers/crypto/virtio/virtio_crypto_common.h b/drivers/crypto/virtio/virtio_crypto_common.h index 19c934af3df6..c758a5a37729 100644 --- a/drivers/crypto/virtio/virtio_crypto_common.h +++ b/drivers/crypto/virtio/virtio_crypto_common.h @@ -11,6 +11,7 @@ #include <linux/crypto.h> #include <linux/spinlock.h> #include <linux/interrupt.h> +#include <linux/workqueue.h> #include <crypto/aead.h> #include <crypto/aes.h> #include <crypto/engine.h> @@ -29,7 +30,7 @@ struct data_queue { char name[32]; struct crypto_engine *engine; - struct tasklet_struct done_task; + struct work_struct done_work; }; struct virtio_crypto { diff --git a/drivers/crypto/virtio/virtio_crypto_core.c b/drivers/crypto/virtio/virtio_crypto_core.c index 3d241446099c..345d1f1ed195 100644 --- a/drivers/crypto/virtio/virtio_crypto_core.c +++ b/drivers/crypto/virtio/virtio_crypto_core.c @@ -70,9 +70,9 @@ int virtio_crypto_ctrl_vq_request(struct virtio_crypto *vcrypto, struct scatterl return 0; } -static void virtcrypto_done_task(unsigned long data) +static void virtcrypto_done_work(struct work_struct *work) { - struct data_queue *data_vq = (struct data_queue *)data; + struct data_queue *data_vq = from_work(data_vq, work, done_work); struct virtqueue *vq = data_vq->vq; struct virtio_crypto_request *vc_req; unsigned int len; @@ -91,7 +91,7 @@ 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); + queue_work(system_bh_wq, &dq->done_work); } static int virtcrypto_find_vqs(struct virtio_crypto *vi) @@ -145,8 +145,7 @@ 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]); + INIT_WORK(&vi->data_vq[i].done_work, virtcrypto_done_work); } kfree(vqs_info); @@ -497,7 +496,7 @@ static void virtcrypto_remove(struct virtio_device *vdev) if (virtcrypto_dev_started(vcrypto)) virtcrypto_dev_stop(vcrypto); for (i = 0; i < vcrypto->max_data_queues; i++) - tasklet_kill(&vcrypto->data_vq[i].done_task); + cancel_work_sync(&vcrypto->data_vq[i].done_work); virtio_reset_device(vdev); virtcrypto_free_unused_reqs(vcrypto); virtcrypto_clear_crypto_engines(vcrypto); -- 2.52.0
