drm/amdgpu: add common HMM get pages function

Move the HMM get pages function from amdgpu_ttm and to amdgpu_mn. This
common function will be used by new svm APIs.

Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c

@@ -155,3 +155,86 @@ void amdgpu_mn_unregister(struct amdgpu_bo *bo)
 	mmu_interval_notifier_remove(&bo->notifier);
 	bo->notifier.mm = NULL;
 }
+
+int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
+			       struct mm_struct *mm, struct page **pages,
+			       uint64_t start, uint64_t npages,
+			       struct hmm_range **phmm_range, bool readonly,
+			       bool mmap_locked)
+{
+	struct hmm_range *hmm_range;
+	unsigned long timeout;
+	unsigned long i;
+	unsigned long *pfns;
+	int r = 0;
+
+	hmm_range = kzalloc(sizeof(*hmm_range), GFP_KERNEL);
+	if (unlikely(!hmm_range))
+		return -ENOMEM;
+
+	pfns = kvmalloc_array(npages, sizeof(*pfns), GFP_KERNEL);
+	if (unlikely(!pfns)) {
+		r = -ENOMEM;
+		goto out_free_range;
+	}
+
+	hmm_range->notifier = notifier;
+	hmm_range->default_flags = HMM_PFN_REQ_FAULT;
+	if (!readonly)
+		hmm_range->default_flags |= HMM_PFN_REQ_WRITE;
+	hmm_range->hmm_pfns = pfns;
+	hmm_range->start = start;
+	hmm_range->end = start + npages * PAGE_SIZE;
+	timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
+
+retry:
+	hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
+
+	if (likely(!mmap_locked))
+		mmap_read_lock(mm);
+
+	r = hmm_range_fault(hmm_range);
+
+	if (likely(!mmap_locked))
+		mmap_read_unlock(mm);
+	if (unlikely(r)) {
+		/*
+		 * FIXME: This timeout should encompass the retry from
+		 * mmu_interval_read_retry() as well.
+		 */
+		if (r == -EBUSY && !time_after(jiffies, timeout))
+			goto retry;
+		goto out_free_pfns;
+	}
+
+	/*
+	 * Due to default_flags, all pages are HMM_PFN_VALID or
+	 * hmm_range_fault() fails. FIXME: The pages cannot be touched outside
+	 * the notifier_lock, and mmu_interval_read_retry() must be done first.
+	 */
+	for (i = 0; pages && i < npages; i++)
+		pages[i] = hmm_pfn_to_page(pfns[i]);
+
+	*phmm_range = hmm_range;
+
+	return 0;
+
+out_free_pfns:
+	kvfree(pfns);
+out_free_range:
+	kfree(hmm_range);
+
+	return r;
+}
+
+int amdgpu_hmm_range_get_pages_done(struct hmm_range *hmm_range)
+{
+	int r;
+
+	r = mmu_interval_read_retry(hmm_range->notifier,
+				    hmm_range->notifier_seq);
+	kvfree(hmm_range->hmm_pfns);
+	kfree(hmm_range);
+
+	return r;
+}

drivers/gpu/drm/amd/amdgpu/amdgpu_mn.h

@@ -30,6 +30,13 @@
 #include <linux/workqueue.h>
 #include <linux/interval_tree.h>
 
+int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier *notifier,
+			       struct mm_struct *mm, struct page **pages,
+			       uint64_t start, uint64_t npages,
+			       struct hmm_range **phmm_range, bool readonly,
+			       bool mmap_locked);
+int amdgpu_hmm_range_get_pages_done(struct hmm_range *hmm_range);
+
 #if defined(CONFIG_HMM_MIRROR)
 int amdgpu_mn_register(struct amdgpu_bo *bo, unsigned long addr);
 void amdgpu_mn_unregister(struct amdgpu_bo *bo);

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -32,7 +32,6 @@
 
 #include <linux/dma-mapping.h>
 #include <linux/iommu.h>
-#include <linux/hmm.h>
 #include <linux/pagemap.h>
 #include <linux/sched/task.h>
 #include <linux/sched/mm.h>
@@ -663,10 +662,8 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 	struct amdgpu_ttm_tt *gtt = (void *)ttm;
 	unsigned long start = gtt->userptr;
 	struct vm_area_struct *vma;
-	struct hmm_range *range;
-	unsigned long timeout;
 	struct mm_struct *mm;
-	unsigned long i;
+	bool readonly;
 	int r = 0;
 
 	mm = bo->notifier.mm;
@@ -682,76 +679,26 @@ int amdgpu_ttm_tt_get_user_pages(struct amdgpu_bo *bo, struct page **pages)
 	if (!mmget_not_zero(mm)) /* Happens during process shutdown */
 		return -ESRCH;
 
-	range = kzalloc(sizeof(*range), GFP_KERNEL);
-	if (unlikely(!range)) {
-		r = -ENOMEM;
-		goto out;
-	}
-	range->notifier = &bo->notifier;
-	range->start = bo->notifier.interval_tree.start;
-	range->end = bo->notifier.interval_tree.last + 1;
-	range->default_flags = HMM_PFN_REQ_FAULT;
-	if (!amdgpu_ttm_tt_is_readonly(ttm))
-		range->default_flags |= HMM_PFN_REQ_WRITE;
-
-	range->hmm_pfns = kvmalloc_array(ttm->num_pages,
-					 sizeof(*range->hmm_pfns), GFP_KERNEL);
-	if (unlikely(!range->hmm_pfns)) {
-		r = -ENOMEM;
-		goto out_free_ranges;
-	}
-
 	mmap_read_lock(mm);
 	vma = find_vma(mm, start);
+	mmap_read_unlock(mm);
 	if (unlikely(!vma || start < vma->vm_start)) {
 		r = -EFAULT;
-		goto out_unlock;
+		goto out_putmm;
 	}
 	if (unlikely((gtt->userflags & AMDGPU_GEM_USERPTR_ANONONLY) &&
 		vma->vm_file)) {
 		r = -EPERM;
-		goto out_unlock;
-	}
-	mmap_read_unlock(mm);
-	timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
-
-retry:
-	range->notifier_seq = mmu_interval_read_begin(&bo->notifier);
-
-	mmap_read_lock(mm);
-	r = hmm_range_fault(range);
-	mmap_read_unlock(mm);
-	if (unlikely(r)) {
-		/*
-		 * FIXME: This timeout should encompass the retry from
-		 * mmu_interval_read_retry() as well.
-		 */
-		if (r == -EBUSY && !time_after(jiffies, timeout))
-			goto retry;
-		goto out_free_pfns;
+		goto out_putmm;
 	}
 
-	/*
-	 * Due to default_flags, all pages are HMM_PFN_VALID or
-	 * hmm_range_fault() fails. FIXME: The pages cannot be touched outside
-	 * the notifier_lock, and mmu_interval_read_retry() must be done first.
-	 */
-	for (i = 0; i < ttm->num_pages; i++)
-		pages[i] = hmm_pfn_to_page(range->hmm_pfns[i]);
-
-	gtt->range = range;
+	readonly = amdgpu_ttm_tt_is_readonly(ttm);
+	r = amdgpu_hmm_range_get_pages(&bo->notifier, mm, pages, start,
+				       ttm->num_pages, &gtt->range, readonly,
+				       false);
+out_putmm:
 	mmput(mm);
 
-	return 0;
-
-out_unlock:
-	mmap_read_unlock(mm);
-out_free_pfns:
-	kvfree(range->hmm_pfns);
-out_free_ranges:
-	kfree(range);
-out:
-	mmput(mm);
 	return r;
 }
 
@@ -780,10 +727,7 @@ bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm)
 		 * FIXME: Must always hold notifier_lock for this, and must
 		 * not ignore the return code.
 		 */
-		r = mmu_interval_read_retry(gtt->range->notifier,
-					 gtt->range->notifier_seq);
-		kvfree(gtt->range->hmm_pfns);
-		kfree(gtt->range);
+		r = amdgpu_hmm_range_get_pages_done(gtt->range);
 		gtt->range = NULL;
 	}