[PATCH] vhost_vdpa: remove unnecessary spin_lock in vhost_vring_call

[Zhu Lingshan]

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....@intel.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. */
-- 
2.18.4