From: Bolarinwa Olayemi Saheed <refactormyself@xxxxxxxxx> MERGING: Only Patch 13/13 depend on all preceeding patchs. All other patches are independent of one another. Hence, please merge PATCH 13/13 only after other patches in this series have been merged. PATCH 6/13: Make the function set status to "Power On" by default and only set to Set "Power Off" only if pcie_capability_read_word() is successful and (slot_ctrl & PCI_EXP_SLTCTL_PCC) == PCI_EXP_SLTCTL_PWR_OFF. PATCH 1/13 to 12/13: Check the return value of pcie_capability_read_*() to ensure success or confirm failure. While maintaining these functions, this ensures that the changes in PATCH 13/13 does not introduce any bug. PATCH 13/13: There are several reasons why a PCI capability read may fail whether the device is present or not. If this happens, pcie_capability_read_*() will return -EINVAL/PCIBIOS_BAD_REGISTER_NUMBER or PCIBIOS_DEVICE_NOT_FOUND and *val is set to 0. This behaviour if further ensured by this code inside pcie_capability_read_*() ret = pci_read_config_dword(dev, pci_pcie_cap(dev) + pos, val); /* * Reset *val to 0 if pci_read_config_dword() fails, it may * have been written as 0xFFFFFFFF if hardware error happens * during pci_read_config_dword(). */ if (ret) *val = 0; return ret; a) Since all pci_generic_config_read() does is read a register value, it may return success after reading a ~0 which *may* have been fabricated by the PCI host bridge due to a read timeout. Hence pci_read_config_*() will return success with a fabricated ~0 in *val, indicating a problem. In this case, the assumed behaviour of pcie_capability_read_*() will be wrong. To avoid error slipping through, more checks are necessary. b) pci_read_config_*() will return PCIBIOS_DEVICE_NOT_FOUND only if dev->error_state = pci_channel_io_perm_failure (i.e. pci_dev_is_disconnected()) or if pci_generic_config_read() can't find the device. In both cases *val is initially set to ~0 but as shown in the code above pcie_capability_read_*() resets it back to 0. Even with this effort, drivers still have to perform validation checks more so if 0 is a valid value. Most drivers only consider the case (b) and in some cases, there is the expectation that on timeout *val has a fabricated value of ~0, which *may* not always be true as explained in (a). In any case, checks need to be done to validate the value read and maybe confirm which error has occurred. It is better left to the drivers to do. Check the return value of pcie_capability_read_dword() to ensure success and avoid bug as a result of Patch 13/13. Remove the reset of *val to 0 when pci_read_config_*() fails. Bolarinwa Olayemi Saheed (13): IB/hfi1: Check the return value of pcie_capability_read_*() misc: rtsx: Check the return value of pcie_capability_read_*() ath9k: Check the return value of pcie_capability_read_*() iwlegacy: Check the return value of pcie_capability_read_*() PCI: pciehp: Check the return value of pcie_capability_read_*() PCI: pciehp: Make "Power On" the default PCI/ACPI: Check the return value of pcie_capability_read_*() PCI: pciehp: Check the return value of pcie_capability_read_*() PCI: Check the return value of pcie_capability_read_*() PCI/PM: Check return value of pcie_capability_read_*() PCI/AER: Check the return value of pcie_capability_read_*() PCI/ASPM: Check the return value of pcie_capability_read_*() PCI: Remove '*val = 0' from pcie_capability_read_*() drivers/net/wireless/ath/ath9k/pci.c | 5 +++-- drivers/net/wireless/intel/iwlegacy/common.c | 4 ++-- drivers/infiniband/hw/hfi1/aspm.c | 7 ++++--- drivers/misc/cardreader/rts5227.c | 5 +++-- drivers/misc/cardreader/rts5249.c | 5 +++-- drivers/misc/cardreader/rts5260.c | 5 +++-- drivers/misc/cardreader/rts5261.c | 5 +++-- drivers/pci/pcie/aer.c | 5 +++-- drivers/pci/pcie/aspm.c | 33 +++++++++++++++++---------------- drivers/pci/hotplug/pciehp_hpc.c | 47 ++++++++++++++++---------------- drivers/pci/pci-acpi.c | 10 ++++--- drivers/pci/probe.c | 29 ++++++++++++-------- drivers/pci/access.c | 14 -------------- 13 files changed, 87 insertions(+), 87 deletions(-) -- 2.18.2
