Subject: [PATCH v4 04/12] iwlegacy: Check if pcie_capability_read_*() reads ~0

From: "Saheed O. Bolarinwa" <[email-masked]>
Date: Fri, 31 Jul 2020 13:02:32 +0200

On failure pcie_capability_read_dword() sets it's last parameter, val
to 0. However, with Patch 12/12, it is possible that val is set to ~0
on failure. This would introduce a bug because (x & x) == (~0 & x).

Since ~0 is an invalid value here,

Add an extra check for ~0 to the if condition to ensure success.

Suggested-by: Bjorn Helgaas <[email-masked]>
Signed-off-by: Saheed O. Bolarinwa <[email-masked]>
---
 drivers/net/wireless/intel/iwlegacy/common.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index 348c17ce72f5..659027563260 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -4287,7 +4287,7 @@ il_apm_init(struct il_priv *il)
 	 */
 	if (il->cfg->set_l0s) {
 		pcie_capability_read_word(il->pci_dev, PCI_EXP_LNKCTL, &lctl);
-		if (lctl & PCI_EXP_LNKCTL_ASPM_L1) {
+		if ((lctl != (u16)~0) && (lctl & PCI_EXP_LNKCTL_ASPM_L1)) {
 			/* L1-ASPM enabled; disable(!) L0S  */
 			il_set_bit(il, CSR_GIO_REG,
 				   CSR_GIO_REG_VAL_L0S_ENABLED);
-- 
2.18.4