From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: [PATCH 21/22] nouveau: unlock mmap_sem on all errors from nouveau_range_fault Date: Mon, 1 Jul 2019 08:20:19 +0200 Message-ID: <20190701062020.19239-22-hch@lst.de> References: <20190701062020.19239-1-hch@lst.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190701062020.19239-1-hch-jcswGhMUV9g@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org Sender: "Linux-nvdimm" To: Dan Williams , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , Jason Gunthorpe , Ben Skeggs Cc: linux-nvdimm-hn68Rpc1hR1g9hUCZPvPmw@public.gmane.org, linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, nouveau-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org List-Id: dri-devel@lists.freedesktop.org Currently nouveau_svm_fault expects nouveau_range_fault to never unlock mmap_sem, but the latter unlocks it for a random selection of error codes. Fix this up by always unlocking mmap_sem for non-zero return values in nouveau_range_fault, and only unlocking it in the caller for successful returns. Signed-off-by: Christoph Hellwig --- drivers/gpu/drm/nouveau/nouveau_svm.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/gpu/drm/nouveau/nouveau_svm.c b/drivers/gpu/drm/nouveau/nouveau_svm.c index e831f4184a17..c0cf7aeaefb3 100644 --- a/drivers/gpu/drm/nouveau/nouveau_svm.c +++ b/drivers/gpu/drm/nouveau/nouveau_svm.c @@ -500,8 +500,10 @@ nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range, ret = hmm_range_register(range, mirror, range->start, range->end, PAGE_SHIFT); - if (ret) + if (ret) { + up_read(&range->vma->vm_mm->mmap_sem); return (int)ret; + } if (!hmm_range_wait_until_valid(range, NOUVEAU_RANGE_FAULT_TIMEOUT)) { /* @@ -515,15 +517,14 @@ nouveau_range_fault(struct hmm_mirror *mirror, struct hmm_range *range, ret = hmm_range_fault(range, block); if (ret <= 0) { - if (ret == -EBUSY || !ret) { - /* Same as above, drop mmap_sem to match old API. */ - up_read(&range->vma->vm_mm->mmap_sem); - ret = -EBUSY; - } else if (ret == -EAGAIN) + if (ret == 0) ret = -EBUSY; + if (ret != -EAGAIN) + up_read(&range->vma->vm_mm->mmap_sem); hmm_range_unregister(range); return ret; } + return 0; } @@ -718,8 +719,8 @@ nouveau_svm_fault(struct nvif_notify *notify) NULL); svmm->vmm->vmm.object.client->super = false; mutex_unlock(&svmm->mutex); + up_read(&svmm->mm->mmap_sem); } - up_read(&svmm->mm->mmap_sem); /* Cancel any faults in the window whose pages didn't manage * to keep their valid bit, or stay writeable when required. -- 2.20.1