[PATCH v2 2/9] PCI: Add additional checks for flr and pm reset

[Farhan Ali <alifm@xxxxxxxxxxxxx>]

If a device is in an error state, then any reads of device registers can
return error value. Add addtional checks to validate if a device is in an
error state before doing an flr or pm reset.

Signed-off-by: Farhan Ali <alifm@xxxxxxxxxxxxx>
---
 drivers/pci/pci.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 0dd95d782022..a07bdb287cf3 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4560,12 +4560,17 @@ EXPORT_SYMBOL_GPL(pcie_flr);
  */
 int pcie_reset_flr(struct pci_dev *dev, bool probe)
 {
+	u32 reg;
+
 	if (dev->dev_flags & PCI_DEV_FLAGS_NO_FLR_RESET)
 		return -ENOTTY;
 
 	if (!(dev->devcap & PCI_EXP_DEVCAP_FLR))
 		return -ENOTTY;
 
+	if (pcie_capability_read_dword(dev, PCI_EXP_DEVCAP, &reg))
+		return -ENOTTY;
+
 	if (probe)
 		return 0;
 
@@ -4640,6 +4645,8 @@ static int pci_pm_reset(struct pci_dev *dev, bool probe)
 		return -ENOTTY;
 
 	pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &csr);
+	if (PCI_POSSIBLE_ERROR(csr))
+		return -ENOTTY;
 	if (csr & PCI_PM_CTRL_NO_SOFT_RESET)
 		return -ENOTTY;
 
-- 
2.43.0