4.18-stable review patch. If anyone has any objections, please let me know.
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From: Marc Zyngier marc.zyngier@arm.com
[ 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 heiko@sntech.de Signed-off-by: Marc Zyngier marc.zyngier@arm.com Signed-off-by: Olof Johansson olof@lixom.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/rockchip-iommu.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)
--- a/drivers/iommu/rockchip-iommu.c +++ b/drivers/iommu/rockchip-iommu.c @@ -521,10 +521,11 @@ static irqreturn_t rk_iommu_irq(int irq, u32 int_status; dma_addr_t iova; irqreturn_t ret = IRQ_NONE; - int i; + int i, err;
- if (WARN_ON(!pm_runtime_get_if_in_use(iommu->dev))) - return 0; + err = pm_runtime_get_if_in_use(iommu->dev); + if (WARN_ON_ONCE(err <= 0)) + return ret;
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_ spin_lock_irqsave(&rk_domain->iommus_lock, flags); list_for_each(pos, &rk_domain->iommus) { struct rk_iommu *iommu; + int ret;
iommu = list_entry(pos, struct rk_iommu, node);
/* Only zap TLBs of IOMMUs that are powered on. */ - if (pm_runtime_get_if_in_use(iommu->dev)) { + ret = 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(struc struct rk_iommu *iommu; struct rk_iommu_domain *rk_domain = to_rk_domain(domain); unsigned long flags; + int ret;
/* Allow 'virtual devices' (eg drm) to detach from domain */ iommu = rk_iommu_from_dev(dev); @@ -909,7 +915,9 @@ static void rk_iommu_detach_device(struc list_del_init(&iommu->node); spin_unlock_irqrestore(&rk_domain->iommus_lock, flags);
- if (pm_runtime_get_if_in_use(iommu->dev)) { + ret = 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 list_add_tail(&iommu->node, &rk_domain->iommus); spin_unlock_irqrestore(&rk_domain->iommus_lock, flags);
- if (!pm_runtime_get_if_in_use(iommu->dev)) + ret = pm_runtime_get_if_in_use(iommu->dev); + if (!ret || WARN_ON_ONCE(ret < 0)) return 0;
ret = rk_iommu_enable(iommu);