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Date:   Mon, 26 Sep 2022 21:30:48 +0800
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Subject: Re: [PATCH 1/3] PCI/AER: Use pci_aer_clear_uncorrect_error_status()
 to clear uncorrectable error status
Content-Language: en-US
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     Serge Semin <fancer.lancer@gmail.com>, allenbh@gmail.com,
        dave.jiang@intel.com, linux-scsi@vger.kernel.org,
        martin.petersen@oracle.com, linux-pci@vger.kernel.org,
        jejb@linux.ibm.com, jdmason@kudzu.us, james.smart@broadcom.com,
        linux-kernel@vger.kernel.org, ntb@lists.linux.dev,
        oohall@gmail.com, bhelgaas@google.com, dick.kennedy@broadcom.com,
        linuxppc-dev@lists.ozlabs.org
References: <20220922200202.GA1330813@bhelgaas>
From:   Zhuo Chen <chenzhuo.1@bytedance.com>
In-Reply-To: <20220922200202.GA1330813@bhelgaas>
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On 9/23/22 4:02 AM, Bjorn Helgaas wrote:
> On Mon, Sep 12, 2022 at 01:09:05AM +0800, Zhuo Chen wrote:
>> On 9/12/22 12:22 AM, Serge Semin wrote:
>>> On Fri, Sep 02, 2022 at 02:16:32AM +0800, Zhuo Chen wrote:
>>>> Status bits for ERR_NONFATAL errors only are cleared in
>>>> pci_aer_clear_nonfatal_status(), but we want clear uncorrectable
>>>> error status in ntb_hw_idt.c and lpfc_attr.c. So we add
>>>> pci_aer_clear_uncorrect_error_status() and change to use it.
>>>
>>> What about the next drivers
>>>
>>> drivers/scsi/lpfc/lpfc_attr.c
>>> drivers/crypto/hisilicon/qm.c
>>> drivers/net/ethernet/intel/ice/ice_main.c
>>>
>>> which call the pci_aer_clear_nonfatal_status() method too?
>>
>> ‘pci_aer_clear_nonfatal_status()’ in
>> drivers/net/ethernet/intel/ice/ice_main.c has already been removed and
>> merged in kernel in: https://github.com/torvalds/linux/commit/ca415ea1f03abf34fc8e4cc5fc30a00189b4e776
> 
> It's better if you can use kernel.org URLs that don't depend on
> third parties like github, e.g.,
> 
>    https://git.kernel.org/linus/ca415ea1f03a
> 
Good reminder, I'll pay attention next time.

>> ‘pci_aer_clear_nonfatal_status()’ in drivers/crypto/hisilicon/qm.c will be
>> removed in the next kernel:
>> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/crypto/hisilicon/qm.c?id=00278564a60e11df8bcca0ececd8b2f55434e406
> 
> This is a problem because 00278564a60e ("crypto: hisilicon - Remove
> pci_aer_clear_nonfatal_status() call") is in Herbert's cryptodev tree,
> and if I apply this series to the PCI tree and Linus merges it before
> Herbert's cryptodev changes, it will break the build.
> 
> I think we need to split this patch up like this:
> 
>    - Add pci_aer_clear_uncorrect_error_status() to PCI core
>    - Convert dpc to use pci_aer_clear_uncorrect_error_status()
>      (I might end up squashing with above)
>    - Convert lpfc to use pci_aer_clear_uncorrect_error_status()
>    - Convert ntb_hw_idt to use pci_aer_clear_uncorrect_error_status()
>    - Unexport pci_aer_clear_nonfatal_status()
> 
> Then I can apply all but the last patch safely.  If the crypto changes
> are merged first, we can add the last one; otherwise we can do it for
> the next cycle.
> 
Good proposal. I will implement these in the next version.

Do I need to put pci related modifications (include patch 2/3 and 3/3) 
in a patch set or just single patches?

>> Uncorrectable error status register was intended to be cleared in
>> drivers/scsi/lpfc/lpfc_attr.c. But originally function was changed in https://github.com/torvalds/linux/commit/e7b0b847de6db161e3917732276e425bc92a2feb
>> and
>> https://github.com/torvalds/linux/commit/894020fdd88c1e9a74c60b67c0f19f1c7696ba2f
> 
> This will be a behavior change for lpfc and ntb_hw_idt.  It looks like
> it changes the behavior back to what it was before e7b0b847de6d
> ("PCI/AER: Clear only ERR_NONFATAL bits during non-fatal recovery"),
> so it might be OK, but splitting these out to their own patches will
> make the change more obvious and we can make sure that's what we want.
> 
> Bjorn

Thanks Bjorn, I will put lpfc and ntb_hw_idt changes in single patchs.
> 
>>>> Use pci_aer_clear_nonfatal_status() in dpc_process_error(), which has
>>>> no functional changes.
>>>>
>>>> Since pci_aer_clear_nonfatal_status() is used only internally, move
>>>> its declaration to the PCI internal header file. Also, no one cares
>>>> about return value of pci_aer_clear_nonfatal_status(), so make it void.
>>>>
>>>> Signed-off-by: Zhuo Chen <chenzhuo.1@bytedance.com>
>>>> ---
>>>>    drivers/ntb/hw/idt/ntb_hw_idt.c |  4 ++--
>>>>    drivers/pci/pci.h               |  2 ++
>>>>    drivers/pci/pcie/aer.c          | 23 ++++++++++++++++++-----
>>>>    drivers/pci/pcie/dpc.c          |  3 +--
>>>>    drivers/scsi/lpfc/lpfc_attr.c   |  4 ++--
>>>>    include/linux/aer.h             |  4 ++--
>>>>    6 files changed, 27 insertions(+), 13 deletions(-)
>>>>
>>>> diff --git a/drivers/ntb/hw/idt/ntb_hw_idt.c b/drivers/ntb/hw/idt/ntb_hw_idt.c
>>>> index 733557231ed0..de1dbbc5b9de 100644
>>>> --- a/drivers/ntb/hw/idt/ntb_hw_idt.c
>>>> +++ b/drivers/ntb/hw/idt/ntb_hw_idt.c
>>>> @@ -2657,8 +2657,8 @@ static int idt_init_pci(struct idt_ntb_dev *ndev)
>>>>    	ret = pci_enable_pcie_error_reporting(pdev);
>>>>    	if (ret != 0)
>>>>    		dev_warn(&pdev->dev, "PCIe AER capability disabled\n");
>>>
>>>> -	else /* Cleanup nonfatal error status before getting to init */
>>>> -		pci_aer_clear_nonfatal_status(pdev);
>>>> +	else /* Cleanup uncorrectable error status before getting to init */
>>>> +		pci_aer_clear_uncorrect_error_status(pdev);
>>>
>>>   From the IDT NTB PCIe initialization procedure point of view both of
>>> these methods are equivalent. So for the IDT NTB part:
>>>
>> IDT NTB part is the same as drivers/scsi/lpfc/lpfc_attr.c. The original
>> function is clear uncorrectable error status register including fatal and
>> non-fatal error status bits.
>>
>>> Acked-by: Serge Semin <fancer.lancer@gmail.com>
>>>
>>> -Sergey
>>>
>>>>    	/* First enable the PCI device */
>>>>    	ret = pcim_enable_device(pdev);
>>>> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
>>>> index e10cdec6c56e..574176f43025 100644
>>>> --- a/drivers/pci/pci.h
>>>> +++ b/drivers/pci/pci.h
>>>> @@ -686,6 +686,7 @@ void pci_aer_init(struct pci_dev *dev);
>>>>    void pci_aer_exit(struct pci_dev *dev);
>>>>    extern const struct attribute_group aer_stats_attr_group;
>>>>    void pci_aer_clear_fatal_status(struct pci_dev *dev);
>>>> +void pci_aer_clear_nonfatal_status(struct pci_dev *dev);
>>>>    int pci_aer_clear_status(struct pci_dev *dev);
>>>>    int pci_aer_raw_clear_status(struct pci_dev *dev);
>>>>    #else
>>>> @@ -693,6 +694,7 @@ static inline void pci_no_aer(void) { }
>>>>    static inline void pci_aer_init(struct pci_dev *d) { }
>>>>    static inline void pci_aer_exit(struct pci_dev *d) { }
>>>>    static inline void pci_aer_clear_fatal_status(struct pci_dev *dev) { }
>>>> +static inline void pci_aer_clear_nonfatal_status(struct pci_dev *dev) { }
>>>>    static inline int pci_aer_clear_status(struct pci_dev *dev) { return -EINVAL; }
>>>>    static inline int pci_aer_raw_clear_status(struct pci_dev *dev) { return -EINVAL; }
>>>>    #endif
>>>> diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
>>>> index 7952e5efd6cf..d2996afa80f6 100644
>>>> --- a/drivers/pci/pcie/aer.c
>>>> +++ b/drivers/pci/pcie/aer.c
>>>> @@ -251,13 +251,13 @@ int pci_disable_pcie_error_reporting(struct pci_dev *dev)
>>>>    }
>>>>    EXPORT_SYMBOL_GPL(pci_disable_pcie_error_reporting);
>>>> -int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>>>> +void pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>>>>    {
>>>>    	int aer = dev->aer_cap;
>>>>    	u32 status, sev;
>>>>    	if (!pcie_aer_is_native(dev))
>>>> -		return -EIO;
>>>> +		return;
>>>>    	/* Clear status bits for ERR_NONFATAL errors only */
>>>>    	pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, &status);
>>>> @@ -265,10 +265,7 @@ int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>>>>    	status &= ~sev;
>>>>    	if (status)
>>>>    		pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status);
>>>> -
>>>> -	return 0;
>>>>    }
>>>> -EXPORT_SYMBOL_GPL(pci_aer_clear_nonfatal_status);
>>>>    void pci_aer_clear_fatal_status(struct pci_dev *dev)
>>>>    {
>>>> @@ -286,6 +283,22 @@ void pci_aer_clear_fatal_status(struct pci_dev *dev)
>>>>    		pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status);
>>>>    }
>>>> +int pci_aer_clear_uncorrect_error_status(struct pci_dev *dev)
>>>> +{
>>>> +	int aer = dev->aer_cap;
>>>> +	u32 status;
>>>> +
>>>> +	if (!pcie_aer_is_native(dev))
>>>> +		return -EIO;
>>>> +
>>>> +	pci_read_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, &status);
>>>> +	if (status)
>>>> +		pci_write_config_dword(dev, aer + PCI_ERR_UNCOR_STATUS, status);
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +EXPORT_SYMBOL_GPL(pci_aer_clear_uncorrect_error_status);
>>>> +
>>>>    /**
>>>>     * pci_aer_raw_clear_status - Clear AER error registers.
>>>>     * @dev: the PCI device
>>>> diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
>>>> index 3e9afee02e8d..7942073fbb34 100644
>>>> --- a/drivers/pci/pcie/dpc.c
>>>> +++ b/drivers/pci/pcie/dpc.c
>>>> @@ -288,8 +288,7 @@ void dpc_process_error(struct pci_dev *pdev)
>>>>    		 dpc_get_aer_uncorrect_severity(pdev, &info) &&
>>>>    		 aer_get_device_error_info(pdev, &info)) {
>>>>    		aer_print_error(pdev, &info);
>>>> -		pci_aer_clear_nonfatal_status(pdev);
>>>> -		pci_aer_clear_fatal_status(pdev);
>>>> +		pci_aer_clear_uncorrect_error_status(pdev);
>>>>    	}
>>>>    }
>>>> diff --git a/drivers/scsi/lpfc/lpfc_attr.c b/drivers/scsi/lpfc/lpfc_attr.c
>>>> index 3caaa7c4af48..1ed8d1640325 100644
>>>> --- a/drivers/scsi/lpfc/lpfc_attr.c
>>>> +++ b/drivers/scsi/lpfc/lpfc_attr.c
>>>> @@ -4712,7 +4712,7 @@ static DEVICE_ATTR_RW(lpfc_aer_support);
>>>>     * Description:
>>>>     * If the @buf contains 1 and the device currently has the AER support
>>>>     * enabled, then invokes the kernel AER helper routine
>>>> - * pci_aer_clear_nonfatal_status() to clean up the uncorrectable
>>>> + * pci_aer_clear_uncorrect_error_status() to clean up the uncorrectable
>>>>     * error status register.
>>>>     *
>>>>     * Notes:
>>>> @@ -4738,7 +4738,7 @@ lpfc_aer_cleanup_state(struct device *dev, struct device_attribute *attr,
>>>>    		return -EINVAL;
>>>>    	if (phba->hba_flag & HBA_AER_ENABLED)
>>>> -		rc = pci_aer_clear_nonfatal_status(phba->pcidev);
>>>> +		rc = pci_aer_clear_uncorrect_error_status(phba->pcidev);
>>>>    	if (rc == 0)
>>>>    		return strlen(buf);
>>>> diff --git a/include/linux/aer.h b/include/linux/aer.h
>>>> index 97f64ba1b34a..f638ad955deb 100644
>>>> --- a/include/linux/aer.h
>>>> +++ b/include/linux/aer.h
>>>> @@ -44,7 +44,7 @@ struct aer_capability_regs {
>>>>    /* PCIe port driver needs this function to enable AER */
>>>>    int pci_enable_pcie_error_reporting(struct pci_dev *dev);
>>>>    int pci_disable_pcie_error_reporting(struct pci_dev *dev);
>>>> -int pci_aer_clear_nonfatal_status(struct pci_dev *dev);
>>>> +int pci_aer_clear_uncorrect_error_status(struct pci_dev *dev);
>>>>    void pci_save_aer_state(struct pci_dev *dev);
>>>>    void pci_restore_aer_state(struct pci_dev *dev);
>>>>    #else
>>>> @@ -56,7 +56,7 @@ static inline int pci_disable_pcie_error_reporting(struct pci_dev *dev)
>>>>    {
>>>>    	return -EINVAL;
>>>>    }
>>>> -static inline int pci_aer_clear_nonfatal_status(struct pci_dev *dev)
>>>> +static inline int pci_aer_clear_uncorrect_error_status(struct pci_dev *dev)
>>>>    {
>>>>    	return -EINVAL;
>>>>    }
>>>> -- 
>>>> 2.30.1 (Apple Git-130)
>>>>
>>
>> -- 
>> Thanks,
>> Zhuo Chen

-- 
Thanks,
Zhuo Chen