From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr730114.outbound.protection.outlook.com ([40.107.73.114]:49585 "EHLO NAM05-DM3-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727205AbeH3WEh (ORCPT ); Thu, 30 Aug 2018 18:04:37 -0400 From: Sasha Levin To: "stable@vger.kernel.org" CC: Marc Zyngier , Olof Johansson , Sasha Levin Subject: [PATCH AUTOSEL 4.18 008/113] iommu/rockchip: Handle errors returned from PM framework Date: Thu, 30 Aug 2018 18:01:16 +0000 Message-ID: <20180830180050.35735-8-alexander.levin@microsoft.com> References: <20180830180050.35735-1-alexander.levin@microsoft.com> In-Reply-To: <20180830180050.35735-1-alexander.levin@microsoft.com> Content-Language: en-US Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org List-ID: From: Marc Zyngier [ Upstream commit 3fc7c5c0cff3150e471f5fd12f59971c6d2c6513 ] pm_runtime_get_if_in_use can fail: either PM has been disabled altogether (-EINVAL), or the device hasn't been enabled yet (0). Sadly, the Rockchip IOMMU driver tends to conflate the two things by considering a non-zero return value as successful. This has the consequence of hiding other bugs, so let's handle this case throughout the driver, with a WARN_ON_ONCE so that we can try and work out what happened. Fixes: 0f181d3cf7d98 ("iommu/rockchip: Add runtime PM support") Reviewed-by: Heiko Stuebner Signed-off-by: Marc Zyngier Signed-off-by: Olof Johansson Signed-off-by: Sasha Levin --- drivers/iommu/rockchip-iommu.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.= c index 054cd2c8e9c8..4e0f9b61cd7f 100644 --- a/drivers/iommu/rockchip-iommu.c +++ b/drivers/iommu/rockchip-iommu.c @@ -521,10 +521,11 @@ static irqreturn_t rk_iommu_irq(int irq, void *dev_id= ) u32 int_status; dma_addr_t iova; irqreturn_t ret =3D IRQ_NONE; - int i; + int i, err; =20 - if (WARN_ON(!pm_runtime_get_if_in_use(iommu->dev))) - return 0; + err =3D pm_runtime_get_if_in_use(iommu->dev); + if (WARN_ON_ONCE(err <=3D 0)) + return ret; =20 if (WARN_ON(clk_bulk_enable(iommu->num_clocks, iommu->clocks))) goto out; @@ -620,11 +621,15 @@ static void rk_iommu_zap_iova(struct rk_iommu_domain = *rk_domain, spin_lock_irqsave(&rk_domain->iommus_lock, flags); list_for_each(pos, &rk_domain->iommus) { struct rk_iommu *iommu; + int ret; =20 iommu =3D list_entry(pos, struct rk_iommu, node); =20 /* Only zap TLBs of IOMMUs that are powered on. */ - if (pm_runtime_get_if_in_use(iommu->dev)) { + ret =3D pm_runtime_get_if_in_use(iommu->dev); + if (WARN_ON_ONCE(ret < 0)) + continue; + if (ret) { WARN_ON(clk_bulk_enable(iommu->num_clocks, iommu->clocks)); rk_iommu_zap_lines(iommu, iova, size); @@ -891,6 +896,7 @@ static void rk_iommu_detach_device(struct iommu_domain = *domain, struct rk_iommu *iommu; struct rk_iommu_domain *rk_domain =3D to_rk_domain(domain); unsigned long flags; + int ret; =20 /* Allow 'virtual devices' (eg drm) to detach from domain */ iommu =3D rk_iommu_from_dev(dev); @@ -909,7 +915,9 @@ static void rk_iommu_detach_device(struct iommu_domain = *domain, list_del_init(&iommu->node); spin_unlock_irqrestore(&rk_domain->iommus_lock, flags); =20 - if (pm_runtime_get_if_in_use(iommu->dev)) { + ret =3D pm_runtime_get_if_in_use(iommu->dev); + WARN_ON_ONCE(ret < 0); + if (ret > 0) { rk_iommu_disable(iommu); pm_runtime_put(iommu->dev); } @@ -946,7 +954,8 @@ static int rk_iommu_attach_device(struct iommu_domain *= domain, list_add_tail(&iommu->node, &rk_domain->iommus); spin_unlock_irqrestore(&rk_domain->iommus_lock, flags); =20 - if (!pm_runtime_get_if_in_use(iommu->dev)) + ret =3D pm_runtime_get_if_in_use(iommu->dev); + if (!ret || WARN_ON_ONCE(ret < 0)) return 0; =20 ret =3D rk_iommu_enable(iommu); --=20 2.17.1