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From:   Johan Hovold <johan+linaro@kernel.org>
To:     "Lorenzo Pieralisi" <lpieralisi@kernel.org>,
        =?UTF-8?q?Krzysztof=20Wilczy=C5=84ski?= <kw@linux.com>,
        "Bjorn Helgaas" <bhelgaas@google.com>
Cc:     Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Manivannan Sadhasivam <mani@kernel.org>,
        Rob Herring <robh@kernel.org>,
        Nirmal Patel <nirmal.patel@linux.intel.com>,
        Jonathan Derrick <jonathan.derrick@linux.dev>,
        linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Johan Hovold <johan+linaro@kernel.org>
Subject: [PATCH v2 0/6] PCI: Fix deadlocks when enabling ASPM
Date:   Tue, 28 Nov 2023 09:15:06 +0100
Message-ID: <20231128081512.19387-1-johan+linaro@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The pci_enable_link_state() helper is currently only called from
pci_walk_bus(), something which can lead to a deadlock as both helpers
take a pci_bus_sem read lock.

Add a new locked helper which can be called with the read lock held and
fix up the two current users (the second is new in 6.7-rc1).

Note that there are no users left of the original unlocked variant after
this series, but I decided to leave it in place for now (e.g. to mirror
the corresponding helpers to disable link states).

Included are also a couple of related cleanups.

Johan


Changes in v2
 - fix up the function name in a kernel doc comment as reported by the
   kernel test robot <lkp@intel.com>


Johan Hovold (6):
  PCI/ASPM: Add locked helper for enabling link state
  PCI: vmd: Fix deadlock when enabling ASPM
  PCI: qcom: Fix deadlock when enabling ASPM
  PCI: qcom: Clean up ASPM comment
  PCI/ASPM: Clean up disable link state parameter
  PCI/ASPM: Add lockdep assert to link state helper

 drivers/pci/controller/dwc/pcie-qcom.c |  7 ++-
 drivers/pci/controller/vmd.c           |  2 +-
 drivers/pci/pcie/aspm.c                | 65 +++++++++++++++++++-------
 include/linux/pci.h                    |  3 ++
 4 files changed, 56 insertions(+), 21 deletions(-)

-- 
2.41.0