| Message ID | 1383759663-3426-1-git-send-email-thellstrom@vmware.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Nov 06, 2013 at 09:41:03AM -0800, Thomas Hellstrom wrote: > Fix a long-standing TTM issue where we manipulated the vma page_prot > bits while mmap_sem was taken in read mode only. We now make a local > copy of the vma structure which we pass when we set the ptes. > > Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> Reviewed-by: Jerome Glisse <jglisse@redhat.com> > --- > drivers/gpu/drm/ttm/ttm_bo_vm.c | 30 +++++++++++++----------------- > 1 file changed, 13 insertions(+), 17 deletions(-) > > diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c > index c03514b..ac617f3 100644 > --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c > +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c > @@ -102,6 +102,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) > int retval = VM_FAULT_NOPAGE; > struct ttm_mem_type_manager *man = > &bdev->man[bo->mem.mem_type]; > + struct vm_area_struct cvma; > > /* > * Work around locking order reversal in fault / nopfn > @@ -164,26 +165,21 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) > } > > /* > - * Strictly, we're not allowed to modify vma->vm_page_prot here, > - * since the mmap_sem is only held in read mode. However, we > - * modify only the caching bits of vma->vm_page_prot and > - * consider those bits protected by > - * the bo->mutex, as we should be the only writers. > - * There shouldn't really be any readers of these bits except > - * within vm_insert_mixed()? fork? > - * > - * TODO: Add a list of vmas to the bo, and change the > - * vma->vm_page_prot when the object changes caching policy, with > - * the correct locks held. > + * Make a local vma copy to modify the page_prot member > + * and vm_flags if necessary. The vma parameter is protected > + * by mmap_sem in write mode. > */ > + cvma = *vma; > + cvma.vm_page_prot = vm_get_page_prot(cvma.vm_flags); > + > if (bo->mem.bus.is_iomem) { > - vma->vm_page_prot = ttm_io_prot(bo->mem.placement, > - vma->vm_page_prot); > + cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, > + cvma.vm_page_prot); > } else { > ttm = bo->ttm; > - vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ? > - vm_get_page_prot(vma->vm_flags) : > - ttm_io_prot(bo->mem.placement, vma->vm_page_prot); > + if (!(bo->mem.placement & TTM_PL_FLAG_CACHED)) > + cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, > + cvma.vm_page_prot); > > /* Allocate all page at once, most common usage */ > if (ttm->bdev->driver->ttm_tt_populate(ttm)) { > @@ -210,7 +206,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) > pfn = page_to_pfn(page); > } > > - ret = vm_insert_mixed(vma, address, pfn); > + ret = vm_insert_mixed(&cvma, address, pfn); > /* > * Somebody beat us to this PTE or prefaulting to > * an already populated PTE, or prefaulting error. > -- > 1.7.10.4 > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index c03514b..ac617f3 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -102,6 +102,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) int retval = VM_FAULT_NOPAGE; struct ttm_mem_type_manager *man = &bdev->man[bo->mem.mem_type]; + struct vm_area_struct cvma; /* * Work around locking order reversal in fault / nopfn @@ -164,26 +165,21 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) } /* - * Strictly, we're not allowed to modify vma->vm_page_prot here, - * since the mmap_sem is only held in read mode. However, we - * modify only the caching bits of vma->vm_page_prot and - * consider those bits protected by - * the bo->mutex, as we should be the only writers. - * There shouldn't really be any readers of these bits except - * within vm_insert_mixed()? fork? - * - * TODO: Add a list of vmas to the bo, and change the - * vma->vm_page_prot when the object changes caching policy, with - * the correct locks held. + * Make a local vma copy to modify the page_prot member + * and vm_flags if necessary. The vma parameter is protected + * by mmap_sem in write mode. */ + cvma = *vma; + cvma.vm_page_prot = vm_get_page_prot(cvma.vm_flags); + if (bo->mem.bus.is_iomem) { - vma->vm_page_prot = ttm_io_prot(bo->mem.placement, - vma->vm_page_prot); + cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, + cvma.vm_page_prot); } else { ttm = bo->ttm; - vma->vm_page_prot = (bo->mem.placement & TTM_PL_FLAG_CACHED) ? - vm_get_page_prot(vma->vm_flags) : - ttm_io_prot(bo->mem.placement, vma->vm_page_prot); + if (!(bo->mem.placement & TTM_PL_FLAG_CACHED)) + cvma.vm_page_prot = ttm_io_prot(bo->mem.placement, + cvma.vm_page_prot); /* Allocate all page at once, most common usage */ if (ttm->bdev->driver->ttm_tt_populate(ttm)) { @@ -210,7 +206,7 @@ static int ttm_bo_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) pfn = page_to_pfn(page); } - ret = vm_insert_mixed(vma, address, pfn); + ret = vm_insert_mixed(&cvma, address, pfn); /* * Somebody beat us to this PTE or prefaulting to * an already populated PTE, or prefaulting error.
Fix a long-standing TTM issue where we manipulated the vma page_prot bits while mmap_sem was taken in read mode only. We now make a local copy of the vma structure which we pass when we set the ptes. Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com> --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-)