[PATCH 5/7] drm/gpusvm: lower get/unmap pages

[Matthew Auld <matthew.auld@intel.com>]

Lower get/unmap pages to facilitate operating on the lowest level
pieces, without needing a full drm_gpusvm_range structure. In the next
patch we want to extract get/unmap/free to operate on a different range
type.

Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/drm_gpusvm.c | 90 ++++++++++++++++++++++--------------
 1 file changed, 55 insertions(+), 35 deletions(-)

diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
index f27731a51f34..2beca5a6dc0a 100644
--- a/drivers/gpu/drm/drm_gpusvm.c
+++ b/drivers/gpu/drm/drm_gpusvm.c
@@ -1323,38 +1323,28 @@ drm_gpusvm_range_pages_valid_unlocked(struct drm_gpusvm *gpusvm,
 	return pages_valid;
 }
 
-/**
- * drm_gpusvm_range_get_pages() - Get pages for a GPU SVM range
- * @gpusvm: Pointer to the GPU SVM structure
- * @range: Pointer to the GPU SVM range structure
- * @ctx: GPU SVM context
- *
- * This function gets pages for a GPU SVM range and ensures they are mapped for
- * DMA access.
- *
- * Return: 0 on success, negative error code on failure.
- */
-int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
-			       struct drm_gpusvm_range *range,
-			       const struct drm_gpusvm_ctx *ctx)
+static int drm_gpusvm_get_pages(struct drm_gpusvm *gpusvm,
+				struct drm_gpusvm_pages *svm_pages,
+				struct mm_struct *mm,
+				struct mmu_interval_notifier *notifier,
+				unsigned long *notifier_seq,
+				unsigned long mm_start,
+				unsigned long mm_end,
+				const struct drm_gpusvm_ctx *ctx)
 {
-	struct drm_gpusvm_pages *svm_pages = &range->pages;
-	struct mmu_interval_notifier *notifier = &range->notifier->notifier;
 	struct hmm_range hmm_range = {
 		.default_flags = HMM_PFN_REQ_FAULT | (ctx->read_only ? 0 :
 			HMM_PFN_REQ_WRITE),
 		.notifier = notifier,
-		.start = drm_gpusvm_range_start(range),
-		.end = drm_gpusvm_range_end(range),
+		.start = mm_start,
+		.end = mm_end,
 		.dev_private_owner = gpusvm->device_private_page_owner,
 	};
-	struct mm_struct *mm = gpusvm->mm;
 	struct drm_gpusvm_zdd *zdd;
 	unsigned long timeout =
 		jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 	unsigned long i, j;
-	unsigned long npages = npages_in_range(drm_gpusvm_range_start(range),
-					       drm_gpusvm_range_end(range));
+	unsigned long npages = npages_in_range(mm_start, mm_end);
 	unsigned long num_dma_mapped;
 	unsigned int order = 0;
 	unsigned long *pfns;
@@ -1518,7 +1508,7 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
 	drm_gpusvm_notifier_unlock(gpusvm);
 	kvfree(pfns);
 set_seqno:
-	range->notifier_seq = hmm_range.notifier_seq;
+	*notifier_seq = hmm_range.notifier_seq;
 
 	return 0;
 
@@ -1531,8 +1521,48 @@ int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
 		goto retry;
 	return err;
 }
+
+/**
+ * drm_gpusvm_range_get_pages() - Get pages for a GPU SVM range
+ * @gpusvm: Pointer to the GPU SVM structure
+ * @range: Pointer to the GPU SVM range structure
+ * @ctx: GPU SVM context
+ *
+ * This function gets pages for a GPU SVM range and ensures they are mapped for
+ * DMA access.
+ *
+ * Return: 0 on success, negative error code on failure.
+ */
+int drm_gpusvm_range_get_pages(struct drm_gpusvm *gpusvm,
+			       struct drm_gpusvm_range *range,
+			       const struct drm_gpusvm_ctx *ctx)
+{
+	return drm_gpusvm_get_pages(gpusvm, &range->pages, gpusvm->mm,
+				    &range->notifier->notifier,
+				    &range->notifier_seq,
+				    drm_gpusvm_range_start(range),
+				    drm_gpusvm_range_end(range), ctx);
+}
 EXPORT_SYMBOL_GPL(drm_gpusvm_range_get_pages);
 
+static void drm_gpusvm_unmap_pages(struct drm_gpusvm *gpusvm,
+				   unsigned long mm_start, unsigned long mm_end,
+				   struct drm_gpusvm_pages *svm_pages,
+				   const struct drm_gpusvm_ctx *ctx)
+{
+	unsigned long npages = npages_in_range(mm_start, mm_end);
+
+	if (ctx->in_notifier)
+		lockdep_assert_held_write(&gpusvm->notifier_lock);
+	else
+		drm_gpusvm_notifier_lock(gpusvm);
+
+	__drm_gpusvm_unmap_pages(gpusvm, svm_pages, npages);
+
+	if (!ctx->in_notifier)
+		drm_gpusvm_notifier_unlock(gpusvm);
+}
+
 /**
  * drm_gpusvm_range_unmap_pages() - Unmap pages associated with a GPU SVM range
  * @gpusvm: Pointer to the GPU SVM structure
@@ -1549,19 +1579,9 @@ void drm_gpusvm_range_unmap_pages(struct drm_gpusvm *gpusvm,
 				  struct drm_gpusvm_range *range,
 				  const struct drm_gpusvm_ctx *ctx)
 {
-	struct drm_gpusvm_pages *svm_pages = &range->pages;
-	unsigned long npages = npages_in_range(drm_gpusvm_range_start(range),
-					       drm_gpusvm_range_end(range));
-
-	if (ctx->in_notifier)
-		lockdep_assert_held_write(&gpusvm->notifier_lock);
-	else
-		drm_gpusvm_notifier_lock(gpusvm);
-
-	__drm_gpusvm_unmap_pages(gpusvm, svm_pages, npages);
-
-	if (!ctx->in_notifier)
-		drm_gpusvm_notifier_unlock(gpusvm);
+	return drm_gpusvm_unmap_pages(gpusvm, drm_gpusvm_range_start(range),
+				      drm_gpusvm_range_end(range),
+				      &range->pages, ctx);
 }
 EXPORT_SYMBOL_GPL(drm_gpusvm_range_unmap_pages);
 
-- 
2.48.1