[RFC PATCH 28/42] drm/i915: Split out GTT fault handler to make it generic

Matthew Auld
2019-02-14T14:58:18Z

From: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>

In preparation for using multiple page-fault handlers depending
on the object's backing storage.

Signed-off-by: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
---
drivers/gpu/drm/i915/i915_gem.c | 112 +++++++++++++++++++-------------
1 file changed, 66 insertions(+), 46 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index e59f38e00f0d..95e31529a738 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1782,11 +1782,7 @@ compute_partial_view(const struct drm_i915_gem_object *obj,
}

/**
- * i915_gem_fault - fault a page into the GTT
- * @vmf: fault info
- *
- * The fault handler is set up by drm_gem_mmap() when a object is GTT mapped
- * from userspace. The fault handler takes care of binding the object to
+ * The GTT fill pages handler takes care of binding the object to
* the GTT (if needed), allocating and programming a fence register (again,
* only if needed based on whether the old reg is still valid or the object
* is tiled) and inserting a new PTE into the faulting process.
@@ -1799,57 +1795,20 @@ compute_partial_view(const struct drm_i915_gem_object *obj,
* The current feature set supported by i915_gem_fault() and thus GTT mmaps
* is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version).
*/
-vm_fault_t i915_gem_fault(struct vm_fault *vmf)
+static int __vmf_fill_pages_gtt(struct drm_i915_gem_object *obj,
+ struct vm_fault *vmf,
+ pgoff_t page_offset)
{
#define MIN_CHUNK_PAGES (SZ_1M >> PAGE_SHIFT)
struct vm_area_struct *area = vmf->vma;
- struct drm_i915_gem_object *obj = to_intel_bo(area->vm_private_data);
struct drm_device *dev = obj->base.dev;
struct drm_i915_private *dev_priv = to_i915(dev);
struct i915_ggtt *ggtt = &dev_priv->ggtt;
bool write = area->vm_flags & VM_WRITE;
- intel_wakeref_t wakeref;
struct i915_vma *vma;
- pgoff_t page_offset;
int srcu;
int ret;

- /* Sanity check that we allow writing into this object */
- if (i915_gem_object_is_readonly(obj) && write)
- return VM_FAULT_SIGBUS;
-
- /* We don't use vmf->pgoff since that has the fake offset */
- page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
-
- trace_i915_gem_object_fault(obj, page_offset, true, write);
-
- /* Try to flush the object off the GPU first without holding the lock.
- * Upon acquiring the lock, we will perform our sanity checks and then
- * repeat the flush holding the lock in the normal manner to catch cases
- * where we are gazumped.
- */
- ret = i915_gem_object_wait(obj,
- I915_WAIT_INTERRUPTIBLE,
- MAX_SCHEDULE_TIMEOUT);
- if (ret)
- goto err;
-
- ret = i915_gem_object_pin_pages(obj);
- if (ret)
- goto err;
-
- wakeref = intel_runtime_pm_get(dev_priv);
-
- ret = i915_mutex_lock_interruptible(dev);
- if (ret)
- goto err_rpm;
-
- /* Access to snoopable pages through the GTT is incoherent. */
- if (obj->cache_level != I915_CACHE_NONE && !HAS_LLC(dev_priv)) {
- ret = -EFAULT;
- goto err_unlock;
- }
-
/* Now pin it into the GTT as needed */
vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0,
PIN_MAPPABLE |
@@ -1880,7 +1839,7 @@ vm_fault_t i915_gem_fault(struct vm_fault *vmf)
}
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
- goto err_unlock;
+ return ret;
}

ret = i915_gem_object_set_to_gtt_domain(obj, write);
@@ -1920,6 +1879,67 @@ vm_fault_t i915_gem_fault(struct vm_fault *vmf)
i915_vma_unpin_fence(vma);
err_unpin:
__i915_vma_unpin(vma);
+
+ return ret;
+}
+
+/**
+ * i915_gem_fault - fault a page into the memory
+ * @vmf: fault info
+ *
+ * The fault handler is set up by drm_gem_mmap() when mmap_offset is called on
+ * an object from userspace. The missing pages are setup by an object's
+ * vmf_fill_pages pages handler, depending on it's backing storage.
+ */
+vm_fault_t i915_gem_fault(struct vm_fault *vmf)
+{
+ struct vm_area_struct *area = vmf->vma;
+ struct drm_i915_gem_object *obj = to_intel_bo(area->vm_private_data);
+ struct drm_device *dev = obj->base.dev;
+ struct drm_i915_private *dev_priv = to_i915(dev);
+ intel_wakeref_t wakeref;
+ bool write = !!(vmf->flags & FAULT_FLAG_WRITE);
+ pgoff_t page_offset;
+ int ret;
+
+ /* Sanity check that we allow writing into this object */
+ if (i915_gem_object_is_readonly(obj) && write)
+ return VM_FAULT_SIGBUS;
+
+ /* We don't use vmf->pgoff since that has the fake offset */
+ page_offset = (vmf->address - area->vm_start) >> PAGE_SHIFT;
+
+ trace_i915_gem_object_fault(obj, page_offset, true, write);
+
+ /* Try to flush the object off the GPU first without holding the lock.
+ * Upon acquiring the lock, we will perform our sanity checks and then
+ * repeat the flush holding the lock in the normal manner to catch cases
+ * where we are gazumped.
+ */
+ ret = i915_gem_object_wait(obj,
+ I915_WAIT_INTERRUPTIBLE,
+ MAX_SCHEDULE_TIMEOUT);
+ if (ret)
+ goto err;
+
+ ret = i915_gem_object_pin_pages(obj);
+ if (ret)
+ goto err;
+
+ wakeref = intel_runtime_pm_get(dev_priv);
+
+ ret = i915_mutex_lock_interruptible(dev);
+ if (ret)
+ goto err_rpm;
+
+ /* Access to snoopable pages through the GTT is incoherent. */
+ if (obj->cache_level != I915_CACHE_NONE && !HAS_LLC(dev_priv)) {
+ ret = -EFAULT;
+ goto err_unlock;
+ }
+
+ ret = __vmf_fill_pages_gtt(obj, vmf, page_offset);
+
err_unlock:
mutex_unlock(&dev->struct_mutex);
err_rpm:
--
2.20.1