From: Chris Wilson Date: Tue, 27 Oct 2020 18:47:59 +0000 (+0000) Subject: drm/i915/gem: Avoid synchronous binds deep within locks X-Git-Tag: v5.15~2259^2~8^2~14 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=c071ab8c20748873183d5f210aa105d6a3e2d56a;p=platform%2Fkernel%2Flinux-starfive.git drm/i915/gem: Avoid synchronous binds deep within locks On bxt, we require a VT'd w/a to serialise all GGTT updates with memory transfers, and use stop_machine() for this purpose. stop_machine() is a global serialisation barrier and so dangerous to use from within critical sections, as the stop_machine() will wait for all cpus to enter the stop_machine callback, and those cpus may be waiting for the critical section already held. Fixes: d7085b0faac8 ("drm/i915/gem: Poison stolen pages before use") Signed-off-by: Chris Wilson Cc: Mika Kuoppala Reviewed-by: Mika Kuoppala Link: https://patchwork.freedesktop.org/patch/msgid/20201027184759.29888-1-chris@chris-wilson.co.uk --- diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c index 78f64a2..69a37a1 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c @@ -505,6 +505,9 @@ static void dbg_poison(struct i915_ggtt *ggtt, if (!drm_mm_node_allocated(&ggtt->error_capture)) return; + if (ggtt->vm.bind_async_flags & I915_VMA_GLOBAL_BIND) + return; /* beware stop_machine() inversion */ + GEM_BUG_ON(!IS_ALIGNED(size, PAGE_SIZE)); mutex_lock(&ggtt->error_mutex);