From 3943875e7b73fdd94dd9e911d69f0cee9ab66a89 Mon Sep 17 00:00:00 2001 From: Thomas Hellstrom Date: Wed, 6 Nov 2013 09:32:59 -0800 Subject: drm/ttm: Fix vma page_prot bit manipulation 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 Reviewed-by: Jerome Glisse --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) (limited to 'drivers/gpu/drm/ttm/ttm_bo_vm.c') diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index c03514b93f9c..ac617f3ecd0c 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. -- cgit