On 08/17/2015 04:52 PM, Inki Dae wrote: > On 2015년 08월 17일 14:29, Joonyoung Shim wrote: >> On 08/16/2015 02:07 PM, Inki Dae wrote: >>> On 2015년 07월 28일 17:53, Joonyoung Shim wrote: >>>> The drm_gem_object_release() function already performs this cleanup, >>>> so there is no reason to do it explicitly. >>>> >>>> Signed-off-by: Joonyoung Shim <jy0922.shim@xxxxxxxxxxx> >>>> --- >>>> drivers/gpu/drm/exynos/exynos_drm_gem.c | 3 --- >>>> 1 file changed, 3 deletions(-) >>>> >>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_gem.c b/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>> index c76aa8a..ab7d029 100644 >>>> --- a/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_gem.c >>>> @@ -100,8 +100,6 @@ out: >>>> exynos_drm_fini_buf(obj->dev, buf); >>>> exynos_gem_obj->buffer = NULL; >>>> >>>> - drm_gem_free_mmap_offset(obj); >>>> - >>>> /* release file pointer to gem object. */ >>>> drm_gem_object_release(obj); >>>> >>>> @@ -600,7 +598,6 @@ int exynos_drm_gem_mmap(struct file *filp, struct vm_area_struct *vma) >>>> >>>> err_close_vm: >>>> drm_gem_vm_close(vma); >>>> - drm_gem_free_mmap_offset(obj); >>> >>> Without previous patch, drm_gem_free_mmap_offset is required. I guess >>> the reason you removed above line is that you thought >>> drm_gem_object_release function would be called by drm_gem_vm_close >>> function which drops a reference of the gem object. >>> >>> However, drm_gem_vm_close should be a pair with drm_gem_vm_open >>> function. These will be called whenever a process opens or closes the >>> VMA. So the reference count of the gem object had already been taken by >>> open operation when a new reference to the VMA had been created. >>> >> >> This changes is not related with drm_gem_vm_close and prior patch. Why >> should free mmap offset when mmap operation is failed? The mmap offset >> can be used repeatedly. > > Isn't vm space of vm manager still used even if any user-space process > doesn't use the region? And if mmap is failed, then the user-space > process will be terminated. Do you think it can be re-tried? However, > mmap system call never return -EAGAIN. Is it reasonable to you? I cannot > understand how the mmap offset can be re-used. So can you show me some > example? > Currently, mmap offset of exynos-drm gem is made by DRM_IOCTL_MODE_MAP_DUMB ioctl and mmap() ioctl just uses the mmap offset. User will use same mmap offset about same gem. It's why mmap offset made by DRM_IOCTL_MODE_MAP_DUMB ioctl is unnecessary, it's just enough to make mmap offset from when gem is create. You can get a reference from drm_gem_cma_helper.c file. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel