From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> 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 <tglx@xxxxxxxxxxxxx> Cc: Christian Koenig <christian.koenig@xxxxxxx> Cc: Huang Rui <ray.huang@xxxxxxx> Cc: David Airlie <airlied@xxxxxxxx> Cc: Daniel Vetter <daniel@xxxxxxxx> Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx --- drivers/gpu/drm/ttm/ttm_bo_util.c | 20 ++++++++++++-------- 1 file changed, 12 insertions(+), 8 deletions(-) --- 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 t 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 t 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; }
