From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Take the minimum of the object size and the vma size and prefault
only that much. Avoids a SIGBUS when mmapping only a portion of the
object.
Prefaulting was introduced here:
commit b90b91d87038f6b257b40a02b42ed4f9705e06f0
Author: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Date: Tue Jun 10 12:14:40 2014 +0100
drm/i915: Prefault the entire object on first page fault
Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/i915_gem.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 6f8c206..4ef80d1 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1578,9 +1578,12 @@ int i915_gem_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
pfn >>= PAGE_SHIFT;
if (!obj->fault_mappable) {
+ unsigned long size = min_t(unsigned long,
+ vma->vm_end - vma->vm_start,
+ obj->base.size);
int i;
- for (i = 0; i < obj->base.size >> PAGE_SHIFT; i++) {
+ for (i = 0; i < size >> PAGE_SHIFT; i++) {
ret = vm_insert_pfn(vma,
(unsigned long)vma->vm_start + i * PAGE_SIZE,
pfn + i);
--
1.8.5.5
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