Date: Sun, 25 Aug 2013 15:06:49 +0000 (UTC) From: Jean-Sebastien Pedron <dumbbell@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r254874 - head/sys/dev/drm2/ttm Message-ID: <201308251506.r7PF6nKT055977@svn.freebsd.org>
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Author: dumbbell Date: Sun Aug 25 15:06:48 2013 New Revision: 254874 URL: http://svnweb.freebsd.org/changeset/base/254874 Log: drm/ttm: Improve comment in ttm_bo_vm_ctor() about lack of ref acquisition Approved by: kib@ Modified: head/sys/dev/drm2/ttm/ttm_bo_vm.c Modified: head/sys/dev/drm2/ttm/ttm_bo_vm.c ============================================================================== --- head/sys/dev/drm2/ttm/ttm_bo_vm.c Sun Aug 25 15:05:22 2013 (r254873) +++ head/sys/dev/drm2/ttm/ttm_bo_vm.c Sun Aug 25 15:06:48 2013 (r254874) @@ -285,8 +285,16 @@ ttm_bo_vm_ctor(void *handle, vm_ooffset_ { /* - * We don't acquire a reference on bo->kref here, because it was - * already done in ttm_bo_mmap_single(). + * On Linux, a reference to the buffer object is acquired here. + * The reason is that this function is not called when the + * mmap() is initialized, but only when a process forks for + * instance. Therefore on Linux, the reference on the bo is + * acquired either in ttm_bo_mmap() or ttm_bo_vm_open(). It's + * then released in ttm_bo_vm_close(). + * + * Here, this function is called during mmap() intialization. + * Thus, the reference acquired in ttm_bo_mmap_single() is + * sufficient. */ *color = 0;
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