* Re: [PATCH] vhost_vdpa: remove unnecessary spin_lock in vhost_vring_call
[not found] <20200909065234.3313-1-lingshan.zhu@intel.com>
@ 2020-09-09 9:04 ` Jason Wang
0 siblings, 0 replies; only message in thread
From: Jason Wang @ 2020-09-09 9:04 UTC (permalink / raw)
To: Zhu Lingshan, mst; +Cc: netdev, kvm, virtualization
On 2020/9/9 下午2:52, Zhu Lingshan wrote:
> This commit removed unnecessary spin_locks in vhost_vring_call
> and related operations. Because we manipulate irq offloading
> contents in vhost_vdpa ioctl code path which is already
> protected by dev mutex and vq mutex.
>
> Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Acked-by: Jason Wang <jasowang@redhat.com>
> ---
> drivers/vhost/vdpa.c | 8 +-------
> drivers/vhost/vhost.c | 3 ---
> drivers/vhost/vhost.h | 1 -
> 3 files changed, 1 insertion(+), 11 deletions(-)
>
> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
> index 3fab94f88894..bc679d0b7b87 100644
> --- a/drivers/vhost/vdpa.c
> +++ b/drivers/vhost/vdpa.c
> @@ -97,26 +97,20 @@ static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
> return;
>
> irq = ops->get_vq_irq(vdpa, qid);
> - spin_lock(&vq->call_ctx.ctx_lock);
> irq_bypass_unregister_producer(&vq->call_ctx.producer);
> - if (!vq->call_ctx.ctx || irq < 0) {
> - spin_unlock(&vq->call_ctx.ctx_lock);
> + if (!vq->call_ctx.ctx || irq < 0)
> return;
> - }
>
> vq->call_ctx.producer.token = vq->call_ctx.ctx;
> vq->call_ctx.producer.irq = irq;
> ret = irq_bypass_register_producer(&vq->call_ctx.producer);
> - spin_unlock(&vq->call_ctx.ctx_lock);
> }
>
> static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)
> {
> struct vhost_virtqueue *vq = &v->vqs[qid];
>
> - spin_lock(&vq->call_ctx.ctx_lock);
> irq_bypass_unregister_producer(&vq->call_ctx.producer);
> - spin_unlock(&vq->call_ctx.ctx_lock);
> }
>
> static void vhost_vdpa_reset(struct vhost_vdpa *v)
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index b45519ca66a7..99f27ce982da 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -302,7 +302,6 @@ static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
> {
> call_ctx->ctx = NULL;
> memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
> - spin_lock_init(&call_ctx->ctx_lock);
> }
>
> static void vhost_vq_reset(struct vhost_dev *dev,
> @@ -1637,9 +1636,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
> break;
> }
>
> - spin_lock(&vq->call_ctx.ctx_lock);
> swap(ctx, vq->call_ctx.ctx);
> - spin_unlock(&vq->call_ctx.ctx_lock);
> break;
> case VHOST_SET_VRING_ERR:
> if (copy_from_user(&f, argp, sizeof f)) {
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 9032d3c2a9f4..486dcf371e06 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -64,7 +64,6 @@ enum vhost_uaddr_type {
> struct vhost_vring_call {
> struct eventfd_ctx *ctx;
> struct irq_bypass_producer producer;
> - spinlock_t ctx_lock;
> };
>
> /* The virtqueue structure describes a queue attached to a device. */
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