From 1cdaafa1b8b4ef6052869c86ba2b41c0cff05957 Mon Sep 17 00:00:00 2001 From: Mike Christie Date: Mon, 26 Jun 2023 18:23:04 -0500 Subject: [PATCH] vhost: replace single worker pointer with xarray The next patch allows userspace to create multiple workers per device, so this patch replaces the vhost_worker pointer with an xarray so we can store mupltiple workers and look them up. Signed-off-by: Mike Christie Message-Id: <20230626232307.97930-15-michael.christie@oracle.com> Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vhost.c | 64 ++++++++++++++++++++++++++++++++----------- drivers/vhost/vhost.h | 3 +- 2 files changed, 50 insertions(+), 17 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 12203d3893c5..ffbaf7d32e2c 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -280,7 +280,11 @@ EXPORT_SYMBOL_GPL(vhost_vq_flush); void vhost_dev_flush(struct vhost_dev *dev) { - vhost_worker_flush(dev->worker); + struct vhost_worker *worker; + unsigned long i; + + xa_for_each(&dev->worker_xa, i, worker) + vhost_worker_flush(worker); } EXPORT_SYMBOL_GPL(vhost_dev_flush); @@ -482,7 +486,6 @@ void vhost_dev_init(struct vhost_dev *dev, dev->umem = NULL; dev->iotlb = NULL; dev->mm = NULL; - dev->worker = NULL; dev->iov_limit = iov_limit; dev->weight = weight; dev->byte_weight = byte_weight; @@ -492,7 +495,7 @@ void vhost_dev_init(struct vhost_dev *dev, INIT_LIST_HEAD(&dev->read_list); INIT_LIST_HEAD(&dev->pending_list); spin_lock_init(&dev->iotlb_lock); - + xa_init_flags(&dev->worker_xa, XA_FLAGS_ALLOC); for (i = 0; i < dev->nvqs; ++i) { vq = dev->vqs[i]; @@ -554,15 +557,35 @@ static void vhost_detach_mm(struct vhost_dev *dev) dev->mm = NULL; } -static void vhost_worker_free(struct vhost_dev *dev) +static void vhost_worker_destroy(struct vhost_dev *dev, + struct vhost_worker *worker) +{ + if (!worker) + return; + + WARN_ON(!llist_empty(&worker->work_list)); + xa_erase(&dev->worker_xa, worker->id); + vhost_task_stop(worker->vtsk); + kfree(worker); +} + +static void vhost_workers_free(struct vhost_dev *dev) { - if (!dev->worker) + struct vhost_worker *worker; + unsigned long i; + + if (!dev->use_worker) return; - WARN_ON(!llist_empty(&dev->worker->work_list)); - vhost_task_stop(dev->worker->vtsk); - kfree(dev->worker); - dev->worker = NULL; + for (i = 0; i < dev->nvqs; i++) + dev->vqs[i]->worker = NULL; + /* + * Free the default worker we created and cleanup workers userspace + * created but couldn't clean up (it forgot or crashed). + */ + xa_for_each(&dev->worker_xa, i, worker) + vhost_worker_destroy(dev, worker); + xa_destroy(&dev->worker_xa); } static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev) @@ -570,6 +593,8 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev) struct vhost_worker *worker; struct vhost_task *vtsk; char name[TASK_COMM_LEN]; + int ret; + u32 id; worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT); if (!worker) @@ -584,16 +609,18 @@ static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev) init_llist_head(&worker->work_list); worker->kcov_handle = kcov_common_handle(); worker->vtsk = vtsk; - /* - * vsock can already try to queue so make sure llist and vtsk are both - * set before vhost_work_queue sees dev->worker is set. - */ - smp_wmb(); - dev->worker = worker; vhost_task_start(vtsk); + + ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL); + if (ret < 0) + goto stop_worker; + worker->id = id; + return worker; +stop_worker: + vhost_task_stop(vtsk); free_worker: kfree(worker); return NULL; @@ -650,6 +677,11 @@ long vhost_dev_set_owner(struct vhost_dev *dev) err = -ENOMEM; goto err_worker; } + /* + * vsock can already try to queue so make sure the worker + * is setup before vhost_vq_work_queue sees vq->worker is set. + */ + smp_wmb(); for (i = 0; i < dev->nvqs; i++) dev->vqs[i]->worker = worker; @@ -751,7 +783,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) dev->iotlb = NULL; vhost_clear_msg(dev); wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); - vhost_worker_free(dev); + vhost_workers_free(dev); vhost_detach_mm(dev); } EXPORT_SYMBOL_GPL(vhost_dev_cleanup); diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h index b850f534bc9a..31937e98c01b 100644 --- a/drivers/vhost/vhost.h +++ b/drivers/vhost/vhost.h @@ -30,6 +30,7 @@ struct vhost_worker { struct vhost_task *vtsk; struct llist_head work_list; u64 kcov_handle; + u32 id; }; /* Poll a file (eventfd or socket) */ @@ -159,7 +160,6 @@ struct vhost_dev { struct vhost_virtqueue **vqs; int nvqs; struct eventfd_ctx *log_ctx; - struct vhost_worker *worker; struct vhost_iotlb *umem; struct vhost_iotlb *iotlb; spinlock_t iotlb_lock; @@ -169,6 +169,7 @@ struct vhost_dev { int iov_limit; int weight; int byte_weight; + struct xarray worker_xa; bool use_worker; int (*msg_handler)(struct vhost_dev *dev, u32 asid, struct vhost_iotlb_msg *msg); -- 2.25.1