Linux-PCI Archive on lore.kernel.org
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From: "Saheed O. Bolarinwa" <refactormyself@gmail.com>
To: helgaas@kernel.org, Kalle Valo <kvalo@codeaurora.org>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>
Cc: "Saheed O. Bolarinwa" <refactormyself@gmail.com>,
	bjorn@helgaas.com, skhan@linuxfoundation.org,
	linux-kernel-mentees@lists.linuxfoundation.org,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	Stanislaw Gruszka <stf_xl@wp.pl>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org
Subject: [PATCH v4 04/12] iwlegacy: Check if pcie_capability_read_*() reads ~0
Date: Fri, 31 Jul 2020 13:02:32 +0200
Message-ID: <20200731110240.98326-5-refactormyself@gmail.com> (raw)
In-Reply-To: <20200731110240.98326-1-refactormyself@gmail.com>

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 <bjorn@helgaas.com>
Signed-off-by: Saheed O. Bolarinwa <refactormyself@gmail.com>
---
 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


  parent reply index

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 11:02 [PATCH v4 00/12] PCI: Remove '*val = 0' from pcie_capability_read_*() Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 01/12] IB/hfi1: Check if pcie_capability_read_*() reads ~0 Saheed O. Bolarinwa
2020-07-31 13:55   ` Bjorn Helgaas
2020-08-03 11:46     ` Ian Kumlien
2020-07-31 11:02 ` [PATCH v4 02/12] misc: rtsx: " Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 03/12] ath9k: " Saheed O. Bolarinwa
2020-07-31 11:02 ` Saheed O. Bolarinwa [this message]
2020-07-31 11:02 ` [PATCH v4 05/12] PCI: pciehp: Set "Power On" as the default get_power_status Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 06/12] PCI: pciehp: Check if pcie_capability_read_*() reads ~0 Saheed O. Bolarinwa
2020-07-31 11:02 ` [PATCH v4 07/12] PCI/ACPI: " Saheed O. Bolarinwa

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