| Message ID | 20200714110445.32605-1-refactormyself@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | PCI: Remove '*val = 0' from pcie_capability_read_*() | expand |
On Tue, Jul 14, 2020 at 01:04:42PM +0200, Saheed Olayemi Bolarinwa wrote: > From: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> > ... > Bolarinwa Olayemi Saheed (14): > 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: pciehp: Check the return value of pcie_capability_read_*() > 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_*() 1) Let's slow down on posting patches. We need time to think and have a conversation about where we're going, and waking up to dozens of new patches every day doesn't help. 2) This series claims to have 14 patches, but only 3 made it to the list. I don't know if the others were rejected for too many folks in the cc: list or what. If you only updated these 3, we will still want the full set of 14 posted because it's too hard to collect 11 things from v3 and 3 things from v4, etc. $ b4 am -om/ 20200714110445.32605-1-refactormyself@gmail.com Looking up https://lore.kernel.org/r/20200714110445.32605-1-refactormyself%40gmail.com Grabbing thread from lore.kernel.org/linux-kernel-mentees Analyzing 4 messages in the thread --- Thread incomplete, attempting to backfill Grabbing thread from lore.kernel.org/linux-rdma Grabbing thread from lore.kernel.org/lkml Grabbing thread from lore.kernel.org/linux-pci --- Writing m/v4_20200714_refactormyself_pci_remove_val_0_from_pcie_capability_read.mbx [PATCH 1/14 v4] IB/hfi1: Check the return value of pcie_capability_read_*() ERROR: missing [2/14]! ERROR: missing [3/14]! ERROR: missing [4/14]! ERROR: missing [5/14]! ERROR: missing [6/14]! ERROR: missing [7/14]! ERROR: missing [8/14]! ERROR: missing [9/14]! [PATCH 10/14 v4] PCI: Check return value of pcie_capability_read_*() [PATCH 11/14 v4] PCI/PM: Check return value of pcie_capability_read_*() ERROR: missing [12/14]! ERROR: missing [13/14]! ERROR: missing [14/14]! --- Total patches: 3 --- WARNING: Thread incomplete! Cover: m/v4_20200714_refactormyself_pci_remove_val_0_from_pcie_capability_read.cover Link: https://lore.kernel.org/r/20200714110445.32605-1-refactormyself@gmail.com Base: not found git am m/v4_20200714_refactormyself_pci_remove_val_0_from_pcie_capability_read.mbx
From: Bolarinwa Olayemi Saheed <refactormyself@gmail.com> v4 CHANGES: - Remove unnecessary boolean conversion - fix bugs introduced by previous version in PATCH 11/14 v3 CHANGES: - Split previous PATCH 6/13 into two : PATCH 6/14 and PATCH 7/14 - Fix commit message of PATCH 5/14 - Update Patch numbering and Commit messages - Add 'Acked by Greg KH' to PATCH 2/14 - Add PATCH version v2 CHANGES: - Fix missing comma, causing the email cc error - Fix typos and numbering errors in commit messages - Add commit message to 13/13 - Add two more patches: PATCH 3/13 and PATCH 4/13 MERGING: Patch 7/14 depends on Patch 6/14. However Patch 6/14 has no dependency. Please, merge PATCH 7/14 only after Patch 6/14. Patch 14/14 depend on all preceeding patchs. Except for Patch 6/14 and Patch 7/14, all other patches are independent of one another. Hence, please merge Patch 14/14 only after other patches in this series have been merged. PATCH 6/14: 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 1/14 to 13/14: 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 14/14 does not introduce any bug. PATCH 14/14: 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 14/14. Remove the reset of *val to 0 when pci_read_config_*() fails. Bolarinwa Olayemi Saheed (14): 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: pciehp: Check the return value of pcie_capability_read_*() 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(-)