From: Bolarinwa Olayemi Saheed <refactormyself@xxxxxxxxx> [ Upstream commit 9018fd7f2a73e9b290f48a56b421558fa31e8b75 ] On failure pcie_capability_read_dword() sets it's last parameter, val to 0. However, with Patch 14/14, it is possible that val is set to ~0 on failure. This would introduce a bug because (x & x) == (~0 & x). This bug can be avoided without changing the function's behaviour if the return value of pcie_capability_read_dword is checked to confirm success. Check the return value of pcie_capability_read_dword() to ensure success. Suggested-by: Bjorn Helgaas <bjorn@xxxxxxxxxxx> Signed-off-by: Bolarinwa Olayemi Saheed <refactormyself@xxxxxxxxx> Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20200713175529.29715-3-refactormyself@xxxxxxxxx Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/wireless/intel/iwlegacy/common.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c index db2373fe8ac32..55573d090503b 100644 --- a/drivers/net/wireless/intel/iwlegacy/common.c +++ b/drivers/net/wireless/intel/iwlegacy/common.c @@ -4302,8 +4302,8 @@ il_apm_init(struct il_priv *il) * power savings, even without L1. */ if (il->cfg->set_l0s) { - pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl); - if (lctl & PCI_EXP_LNKCTL_ASPM_L1) { + ret = pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl); + if (!ret && (lctl & PCI_EXP_LNKCTL_ASPM_L1)) { /* L1-ASPM enabled; disable(!) L0S */ il_set_bit(il, CSR_GIO_REG, CSR_GIO_REG_VAL_L0S_ENABLED); -- 2.25.1
