linux-kernel - [PATCH v2 3/9] PCI/PM: Rearrange pci_update_current

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Message-ID: <4721615.GXAFRqVoOG@kreacher>
Date:   Mon, 11 Apr 2022 16:21:04 +0200
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Linux PCI <linux-pci@...r.kernel.org>
Cc:     Linux PM <linux-pm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Bjorn Helgaas <helgaas@...nel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: [PATCH v2 3/9] PCI/PM: Rearrange pci_update_current_state()

From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

Save one config space access in pci_update_current_state() by
testing the retireved PCI_PM_CTRL register value against
PCI_POSSIBLE_ERROR() instead of invoking pci_device_is_present()
separately.

While at it, drop a pair of unnecessary parens.

No expected functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---

v1 -> v2: No changes.

---
 drivers/pci/pci.c |    9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

Index: linux-pm/drivers/pci/pci.c
===================================================================
--- linux-pm.orig/drivers/pci/pci.c
+++ linux-pm/drivers/pci/pci.c
@@ -1201,14 +1201,17 @@ static int pci_raw_set_power_state(struc
  */
 void pci_update_current_state(struct pci_dev *dev, pci_power_t state)
 {
-	if (platform_pci_get_power_state(dev) == PCI_D3cold ||
-	    !pci_device_is_present(dev)) {
+	if (platform_pci_get_power_state(dev) == PCI_D3cold) {
 		dev->current_state = PCI_D3cold;
 	} else if (dev->pm_cap) {
 		u16 pmcsr;
 
 		pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
-		dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
+		if (PCI_POSSIBLE_ERROR(pmcsr)) {
+			dev->current_state = PCI_D3cold;
+			return;
+		}
+		dev->current_state = pmcsr & PCI_PM_CTRL_STATE_MASK;
 	} else {
 		dev->current_state = state;
 	}