drm/i915: Convert spt_tree to XArray

A straightforward conversion.  Notice the XArray does not suffer from
exposing the RCU problem to its users like the radix tree did.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 4b04af569c05c13df7cc4f6ca235abb0b281d025..87a77bad6e6da09a32a21a232ac39199f5d08337 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -741,7 +741,7 @@ static void ppgtt_free_spt(struct intel_vgpu_ppgtt_spt *spt)
        dma_unmap_page(kdev, spt->shadow_page.mfn << I915_GTT_PAGE_SHIFT, 4096,
                       PCI_DMA_BIDIRECTIONAL);
 
-       radix_tree_delete(&spt->vgpu->gtt.spt_tree, spt->shadow_page.mfn);
+       xa_erase(&spt->vgpu->gtt.spts, spt->shadow_page.mfn);
 
        if (spt->guest_page.gfn) {
                if (spt->guest_page.oos_page)
@@ -756,19 +756,10 @@ static void ppgtt_free_spt(struct intel_vgpu_ppgtt_spt *spt)
 
 static void ppgtt_free_all_spt(struct intel_vgpu *vgpu)
 {
-       struct intel_vgpu_ppgtt_spt *spt, *spn;
-       struct radix_tree_iter iter;
-       LIST_HEAD(all_spt);
-       void __rcu **slot;
-
-       rcu_read_lock();
-       radix_tree_for_each_slot(slot, &vgpu->gtt.spt_tree, &iter, 0) {
-               spt = radix_tree_deref_slot(slot);
-               list_move(&spt->post_shadow_list, &all_spt);
-       }
-       rcu_read_unlock();
+       struct intel_vgpu_ppgtt_spt *spt;
+       unsigned long index;
 
-       list_for_each_entry_safe(spt, spn, &all_spt, post_shadow_list)
+       xa_for_each(&vgpu->gtt.spts, index, spt)
                ppgtt_free_spt(spt);
 }
 
@@ -810,7 +801,7 @@ static struct intel_vgpu_ppgtt_spt *intel_vgpu_find_spt_by_gfn(
 static inline struct intel_vgpu_ppgtt_spt *intel_vgpu_find_spt_by_mfn(
                struct intel_vgpu *vgpu, unsigned long mfn)
 {
-       return radix_tree_lookup(&vgpu->gtt.spt_tree, mfn);
+       return xa_load(&vgpu->gtt.spts, mfn);
 }
 
 static int reclaim_one_ppgtt_mm(struct intel_gvt *gvt);
@@ -852,13 +843,13 @@ retry:
        spt->shadow_page.vaddr = page_address(spt->shadow_page.page);
        spt->shadow_page.mfn = daddr >> I915_GTT_PAGE_SHIFT;
 
-       ret = radix_tree_insert(&vgpu->gtt.spt_tree, spt->shadow_page.mfn, spt);
-       if (ret)
+       if (xa_store(&vgpu->gtt.spts, spt->shadow_page.mfn, spt, GFP_KERNEL))
                goto err_unmap_dma;
 
        return spt;
 
 err_unmap_dma:
+       ret = -ENOMEM;
        dma_unmap_page(kdev, daddr, PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
 err_free_spt:
        free_spt(spt);
@@ -2454,7 +2445,7 @@ int intel_vgpu_init_gtt(struct intel_vgpu *vgpu)
 {
        struct intel_vgpu_gtt *gtt = &vgpu->gtt;
 
-       INIT_RADIX_TREE(&gtt->spt_tree, GFP_KERNEL);
+       xa_init(&gtt->spts);
 
        INIT_LIST_HEAD(&gtt->ppgtt_mm_list_head);
        INIT_LIST_HEAD(&gtt->oos_page_list_head);
@@ -2486,7 +2477,7 @@ static void intel_vgpu_destroy_all_ppgtt_mm(struct intel_vgpu *vgpu)
        if (GEM_WARN_ON(!list_empty(&vgpu->gtt.ppgtt_mm_list_head)))
                gvt_err("vgpu ppgtt mm is not fully destroyed\n");
 
-       if (GEM_WARN_ON(!radix_tree_empty(&vgpu->gtt.spt_tree))) {
+       if (GEM_WARN_ON(!xa_empty(&vgpu->gtt.spts))) {
                gvt_err("Why we still has spt not freed?\n");
                ppgtt_free_all_spt(vgpu);
        }

diff --git a/drivers/gpu/drm/i915/gvt/gtt.h b/drivers/gpu/drm/i915/gvt/gtt.h
index 42d0394f0de2bcd0841fc35f44a7ecc5c8e520f3..b5834a13c599a6429bc8c8e38c1001f593c3185a 100644 (file)
--- a/drivers/gpu/drm/i915/gvt/gtt.h
+++ b/drivers/gpu/drm/i915/gvt/gtt.h
@@ -199,7 +199,7 @@ struct intel_vgpu_gtt {
        struct intel_vgpu_mm *ggtt_mm;
        unsigned long active_ppgtt_mm_bitmap;
        struct list_head ppgtt_mm_list_head;
-       struct radix_tree_root spt_tree;
+       struct xarray spts;
        struct list_head oos_page_list_head;
        struct list_head post_shadow_list_head;
        struct intel_vgpu_scratch_pt scratch_pt[GTT_TYPE_MAX];

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index fe7a6ec2c199c49bd2750b4ac92b2690fada1435..4998250bb2aaa15722e278dd6da3dae072068197 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -46,6 +46,7 @@
 #include <linux/reservation.h>
 #include <linux/shmem_fs.h>
 #include <linux/stackdepot.h>
+#include <linux/xarray.h>
 
 #include <drm/intel-gtt.h>
 #include <drm/drm_legacy.h> /* for struct drm_dma_handle */