From cd9f2293478040e4ee9bb03a5f1bfbc60fe45fa5 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 3 Nov 2020 10:27:43 +0100 Subject: [PATCH 054/323] drm/ttm: Replace kmap_atomic() usage Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.215-rt107.tar.xz There is no reason to disable pagefaults and preemption as a side effect of kmap_atomic_prot(). Use kmap_local_page_prot() instead and document the reasoning for the mapping usage with the given pgprot. Remove the NULL pointer check for the map. These functions return a valid address for valid pages and the return was bogus anyway as it would have left preemption and pagefaults disabled. Signed-off-by: Thomas Gleixner Cc: Christian Koenig Cc: Huang Rui Cc: David Airlie Cc: Daniel Vetter Cc: dri-devel@lists.freedesktop.org Signed-off-by: Sebastian Andrzej Siewior --- drivers/gpu/drm/ttm/ttm_bo_util.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c index 1968df9743fcb..79b9c883431ad 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_util.c +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c @@ -181,13 +181,15 @@ static int ttm_copy_io_ttm_page(struct ttm_tt *ttm, void *src, return -ENOMEM; src = (void *)((unsigned long)src + (page << PAGE_SHIFT)); - dst = kmap_atomic_prot(d, prot); - if (!dst) - return -ENOMEM; + /* + * Ensure that a highmem page is mapped with the correct + * pgprot. For non highmem the mapping is already there. + */ + dst = kmap_local_page_prot(d, prot); memcpy_fromio(dst, src, PAGE_SIZE); - kunmap_atomic(dst); + kunmap_local(dst); return 0; } @@ -203,13 +205,15 @@ static int ttm_copy_ttm_io_page(struct ttm_tt *ttm, void *dst, return -ENOMEM; dst = (void *)((unsigned long)dst + (page << PAGE_SHIFT)); - src = kmap_atomic_prot(s, prot); - if (!src) - return -ENOMEM; + /* + * Ensure that a highmem page is mapped with the correct + * pgprot. For non highmem the mapping is already there. + */ + src = kmap_local_page_prot(s, prot); memcpy_toio(dst, src, PAGE_SIZE); - kunmap_atomic(src); + kunmap_local(src); return 0; } -- 2.44.0