From c8185520aed6faab58b310f573790badfca27981 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 13 Sep 2019 07:42:00 +0100 Subject: [PATCH] drm/i915/gtt: Make sure the gen6 ppgtt is bound before first use As we remove the struct_mutex protection from around the vma pinning, counters need to be atomic and aware that there may be multiple threads simultaneously active. Signed-off-by: Chris Wilson Reviewed-by: Matthew Auld Link: https://patchwork.freedesktop.org/patch/msgid/20190913064200.24297-1-chris@chris-wilson.co.uk --- drivers/gpu/drm/i915/i915_gem_gtt.c | 40 ++++++++++++++++++++----------------- drivers/gpu/drm/i915/i915_gem_gtt.h | 4 +++- 2 files changed, 25 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c index a09a9b6..e62e9d1 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.c +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c @@ -1790,6 +1790,8 @@ static void gen6_ppgtt_cleanup(struct i915_address_space *vm) gen6_ppgtt_free_pd(ppgtt); free_scratch(vm); + + mutex_destroy(&ppgtt->pin_mutex); kfree(ppgtt->base.pd); } @@ -1895,7 +1897,7 @@ static struct i915_vma *pd_vma_create(struct gen6_ppgtt *ppgtt, int size) int gen6_ppgtt_pin(struct i915_ppgtt *base) { struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(base); - int err; + int err = 0; GEM_BUG_ON(ppgtt->base.vm.closed); @@ -1905,24 +1907,26 @@ int gen6_ppgtt_pin(struct i915_ppgtt *base) * (When vma->pin_count becomes atomic, I expect we will naturally * need a larger, unpacked, type and kill this redundancy.) */ - if (ppgtt->pin_count++) + if (atomic_add_unless(&ppgtt->pin_count, 1, 0)) return 0; + if (mutex_lock_interruptible(&ppgtt->pin_mutex)) + return -EINTR; + /* * PPGTT PDEs reside in the GGTT and consists of 512 entries. The * allocator works in address space sizes, so it's multiplied by page * size. We allocate at the top of the GTT to avoid fragmentation. */ - err = i915_vma_pin(ppgtt->vma, - 0, GEN6_PD_ALIGN, - PIN_GLOBAL | PIN_HIGH); - if (err) - goto unpin; - - return 0; + if (!atomic_read(&ppgtt->pin_count)) { + err = i915_vma_pin(ppgtt->vma, + 0, GEN6_PD_ALIGN, + PIN_GLOBAL | PIN_HIGH); + } + if (!err) + atomic_inc(&ppgtt->pin_count); + mutex_unlock(&ppgtt->pin_mutex); -unpin: - ppgtt->pin_count = 0; return err; } @@ -1930,22 +1934,20 @@ void gen6_ppgtt_unpin(struct i915_ppgtt *base) { struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(base); - GEM_BUG_ON(!ppgtt->pin_count); - if (--ppgtt->pin_count) - return; - - i915_vma_unpin(ppgtt->vma); + GEM_BUG_ON(!atomic_read(&ppgtt->pin_count)); + if (atomic_dec_and_test(&ppgtt->pin_count)) + i915_vma_unpin(ppgtt->vma); } void gen6_ppgtt_unpin_all(struct i915_ppgtt *base) { struct gen6_ppgtt *ppgtt = to_gen6_ppgtt(base); - if (!ppgtt->pin_count) + if (!atomic_read(&ppgtt->pin_count)) return; - ppgtt->pin_count = 0; i915_vma_unpin(ppgtt->vma); + atomic_set(&ppgtt->pin_count, 0); } static struct i915_ppgtt *gen6_ppgtt_create(struct drm_i915_private *i915) @@ -1958,6 +1960,8 @@ static struct i915_ppgtt *gen6_ppgtt_create(struct drm_i915_private *i915) if (!ppgtt) return ERR_PTR(-ENOMEM); + mutex_init(&ppgtt->pin_mutex); + ppgtt_init(&ppgtt->base, &i915->gt); ppgtt->base.vm.top = 1; diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.h b/drivers/gpu/drm/i915/i915_gem_gtt.h index 2017881..8fd2234 100644 --- a/drivers/gpu/drm/i915/i915_gem_gtt.h +++ b/drivers/gpu/drm/i915/i915_gem_gtt.h @@ -437,7 +437,9 @@ struct gen6_ppgtt { struct i915_vma *vma; gen6_pte_t __iomem *pd_addr; - unsigned int pin_count; + atomic_t pin_count; + struct mutex pin_mutex; + bool scan_for_unused_pt; }; -- 2.7.4