From 581e2ab5c6cbbc0011ac9c0ac0d02551bbd529f0 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Wed, 10 Jun 2015 15:58:01 +0100 Subject: [PATCH] drm: Avoid the double clflush on the last cache line in drm_clflush_virt_range() As the clflush operates on cache lines, and we can flush any byte address, in order to flush all bytes given in the range we issue an extra clflush on the last byte to ensure the last cacheline is flushed. We can can the iteration to be over the actual cache lines to avoid this double clflush on the last byte. Signed-off-by: Chris Wilson Cc: Imre Deak Reviewed-by: Imre Deak Signed-off-by: Daniel Vetter --- drivers/gpu/drm/drm_cache.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index 9a62d7a53553d..6743ff7dccfa3 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -130,11 +130,12 @@ drm_clflush_virt_range(void *addr, unsigned long length) { #if defined(CONFIG_X86) if (cpu_has_clflush) { + const int size = boot_cpu_data.x86_clflush_size; void *end = addr + length; + addr = (void *)(((unsigned long)addr) & -size); mb(); - for (; addr < end; addr += boot_cpu_data.x86_clflush_size) + for (; addr < end; addr += size) clflushopt(addr); - clflushopt(end - 1); mb(); return; } -- 2.39.5