[PATCH 2/2] nvme-pci: add AMD PCIe quirk for suspend/resume

[Greg KH]

On Wed, Apr 14, 2021 at 10:18:14AM +0800, Prike Liang wrote:
> The NVME device pluged in some AMD PCIE root port will resume timeout
> from s2idle which caused by NVME power CFG lost in the SMU FW restore.
> This issue can be workaround by using PCIe power set with simple
> suspend/resume process path instead of APST. In the onwards ASIC will
> try do the NVME shutdown save and restore in the BIOS and still need
> PCIe power setting to resume from RTD3 for s2idle.
> 
> Update the nvme_acpi_storage_d3() _with previously added quirk.
> 
> Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
> [ck: split patches for nvme and pcie]
> Signed-off-by: Prike Liang <Prike.Liang at amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k at amd.com>
> Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
> Cc: <stable at vger.kernel.org> # 5.11+
> ---
>  drivers/nvme/host/pci.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
> index 6bad4d4..dd46d9e 100644
> --- a/drivers/nvme/host/pci.c
> +++ b/drivers/nvme/host/pci.c
> @@ -2832,6 +2832,7 @@ static bool nvme_acpi_storage_d3(struct pci_dev *dev)
>  {
>  	struct acpi_device *adev;
>  	struct pci_dev *root;
> +	struct pci_dev *rdev;
>  	acpi_handle handle;
>  	acpi_status status;
>  	u8 val;
> @@ -2845,6 +2846,10 @@ static bool nvme_acpi_storage_d3(struct pci_dev *dev)
>  	if (!root)
>  		return false;
>  
> +	rdev = pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(0, 0));
> +	if (rdev->dev_flags & PCI_DEV_FLAGS_AMD_NVME_SIMPLE_SUSPEND)
> +		return NVME_QUIRK_SIMPLE_SUSPEND;
> +

You just leaked a reference count :(

And what if rdev is NULL?