drm/i915/gvt: Revert "drm/i915/gvt: Fix possible recursive locking issue"

This reverts commit 62d02fd1f807bf5a259a242c483c9fb98a242630.

The rwsem recursive trace should not be fixed from kvmgt side by using
a workqueue and it is an issue should be fixed in VFIO. So this one
should be reverted.

Signed-off-by: Chuanxiao Dong <chuanxiao.dong@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: stable@vger.kernel.org # v4.10+
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>

diff --git a/drivers/gpu/drm/i915/gvt/gvt.h b/drivers/gpu/drm/i915/gvt/gvt.h
index 28d817e..3a74e79 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/gvt.h
+++ b/drivers/gpu/drm/i915/gvt/gvt.h
@@ -182,9 +182,6 @@ struct intel_vgpu {
                struct kvm *kvm;
                struct work_struct release_work;
                atomic_t released;
-               struct work_struct unpin_work;
-               spinlock_t unpin_lock; /* To protect unpin_list */
-               struct list_head unpin_list;
        } vdev;
 #endif
 };

diff --git a/drivers/gpu/drm/i915/gvt/kvmgt.c b/drivers/gpu/drm/i915/gvt/kvmgt.c
index 75a6e1d..fd0c85f 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/kvmgt.c
+++ b/drivers/gpu/drm/i915/gvt/kvmgt.c
@@ -78,7 +78,6 @@ struct gvt_dma {
        struct rb_node node;
        gfn_t gfn;
        unsigned long iova;
-       struct list_head list;
 };
 
 static inline bool handle_valid(unsigned long handle)
@@ -167,7 +166,6 @@ static void gvt_cache_add(struct intel_vgpu *vgpu, gfn_t gfn,
 
        new->gfn = gfn;
        new->iova = iova;
-       INIT_LIST_HEAD(&new->list);
 
        mutex_lock(&vgpu->vdev.cache_lock);
        while (*link) {
@@ -199,52 +197,26 @@ static void __gvt_cache_remove_entry(struct intel_vgpu *vgpu,
        kfree(entry);
 }
 
-static void intel_vgpu_unpin_work(struct work_struct *work)
+static void gvt_cache_remove(struct intel_vgpu *vgpu, gfn_t gfn)
 {
-       struct intel_vgpu *vgpu = container_of(work, struct intel_vgpu,
-                                              vdev.unpin_work);
        struct device *dev = mdev_dev(vgpu->vdev.mdev);
        struct gvt_dma *this;
-       unsigned long gfn;
-
-       for (;;) {
-               spin_lock(&vgpu->vdev.unpin_lock);
-               if (list_empty(&vgpu->vdev.unpin_list)) {
-                       spin_unlock(&vgpu->vdev.unpin_lock);
-                       break;
-               }
-               this = list_first_entry(&vgpu->vdev.unpin_list,
-                                       struct gvt_dma, list);
-               list_del(&this->list);
-               spin_unlock(&vgpu->vdev.unpin_lock);
-
-               gfn = this->gfn;
-               vfio_unpin_pages(dev, &gfn, 1);
-               kfree(this);
-       }
-}
-
-static bool gvt_cache_mark_remove(struct intel_vgpu *vgpu, gfn_t gfn)
-{
-       struct gvt_dma *this;
+       unsigned long g1;
+       int rc;
 
        mutex_lock(&vgpu->vdev.cache_lock);
        this  = __gvt_cache_find(vgpu, gfn);
        if (!this) {
                mutex_unlock(&vgpu->vdev.cache_lock);
-               return false;
+               return;
        }
+
+       g1 = gfn;
        gvt_dma_unmap_iova(vgpu, this->iova);
-       /* remove this from rb tree */
-       rb_erase(&this->node, &vgpu->vdev.cache);
+       rc = vfio_unpin_pages(dev, &g1, 1);
+       WARN_ON(rc != 1);
+       __gvt_cache_remove_entry(vgpu, this);
        mutex_unlock(&vgpu->vdev.cache_lock);
-
-       /* put this to the unpin_list */
-       spin_lock(&vgpu->vdev.unpin_lock);
-       list_move_tail(&this->list, &vgpu->vdev.unpin_list);
-       spin_unlock(&vgpu->vdev.unpin_lock);
-
-       return true;
 }
 
 static void gvt_cache_init(struct intel_vgpu *vgpu)
@@ -485,9 +457,6 @@ static int intel_vgpu_create(struct kobject *kobj, struct mdev_device *mdev)
        }
 
        INIT_WORK(&vgpu->vdev.release_work, intel_vgpu_release_work);
-       INIT_WORK(&vgpu->vdev.unpin_work, intel_vgpu_unpin_work);
-       spin_lock_init(&vgpu->vdev.unpin_lock);
-       INIT_LIST_HEAD(&vgpu->vdev.unpin_list);
 
        vgpu->vdev.mdev = mdev;
        mdev_set_drvdata(mdev, vgpu);
@@ -517,7 +486,6 @@ static int intel_vgpu_iommu_notifier(struct notifier_block *nb,
        struct intel_vgpu *vgpu = container_of(nb,
                                        struct intel_vgpu,
                                        vdev.iommu_notifier);
-       bool sched_unmap = false;
 
        if (action == VFIO_IOMMU_NOTIFY_DMA_UNMAP) {
                struct vfio_iommu_type1_dma_unmap *unmap = data;
@@ -527,10 +495,7 @@ static int intel_vgpu_iommu_notifier(struct notifier_block *nb,
                end_gfn = gfn + unmap->size / PAGE_SIZE;
 
                while (gfn < end_gfn)
-                       sched_unmap |= gvt_cache_mark_remove(vgpu, gfn++);
-
-               if (sched_unmap)
-                       schedule_work(&vgpu->vdev.unpin_work);
+                       gvt_cache_remove(vgpu, gfn++);
        }
 
        return NOTIFY_OK;