From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Daniel Vetter Subject: [PATCH 3/4] mm, notifier: Catch sleeping/blocking for !blockable Date: Mon, 10 Dec 2018 11:36:40 +0100 Message-Id: <20181210103641.31259-4-daniel.vetter@ffwll.ch> In-Reply-To: <20181210103641.31259-1-daniel.vetter@ffwll.ch> References: <20181210103641.31259-1-daniel.vetter@ffwll.ch> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org To: Intel Graphics Development Cc: DRI Development , LKML , linux-mm@kvack.org, Daniel Vetter , Andrew Morton , Michal Hocko , David Rientjes , =?UTF-8?q?Christian=20K=C3=B6nig?= , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Daniel Vetter List-ID: We need to make sure implementations don't cheat and don't have a possible schedule/blocking point deeply burried where review can't catch it. I'm not sure whether this is the best way to make sure all the might_sleep() callsites trigger, and it's a bit ugly in the code flow. But it gets the job done. Inspired by an i915 patch series which did exactly that, because the rules haven't been entirely clear to us. v2: Use the shiny new non_block_start/end annotations instead of abusing preempt_disable/enable. Cc: Andrew Morton Cc: Michal Hocko Cc: David Rientjes Cc: "Christian König" Cc: Daniel Vetter Cc: "Jérôme Glisse" Cc: linux-mm@kvack.org Signed-off-by: Daniel Vetter --- mm/mmu_notifier.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index ccc22f21b735..a50ed7d1ecef 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -185,7 +185,13 @@ int __mmu_notifier_invalidate_range_start(struct mm_struct *mm, id = srcu_read_lock(&srcu); hlist_for_each_entry_rcu(mn, &mm->mmu_notifier_mm->list, hlist) { if (mn->ops->invalidate_range_start) { - int _ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable); + int _ret; + + if (!blockable) + non_block_start(); + _ret = mn->ops->invalidate_range_start(mn, mm, start, end, blockable); + if (!blockable) + non_block_end(); if (_ret) { pr_info("%pS callback failed with %d in %sblockable context.\n", mn->ops->invalidate_range_start, _ret, -- 2.20.0.rc1