From: Ville Syrjälä Date: Tue, 17 Jun 2014 18:03:00 +0000 (+0300) Subject: drm/i915: Don't prefault the entire obj if the vma is smaller X-Git-Tag: v3.17-rc1~82^2~63^2~21 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=beff0d0f6121f6a2a818a050a1e4d91706b3f190;p=karo-tx-linux.git drm/i915: Don't prefault the entire obj if the vma is smaller 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 Date: Tue Jun 10 12:14:40 2014 +0100 drm/i915: Prefault the entire object on first page fault Cc: Chris Wilson Signed-off-by: Ville Syrjälä Testcase: igt/gem_mmap/short-mmap Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 7f643db26829..d8364135c2e5 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1570,9 +1570,12 @@ 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);