linux-kernel - [PATCH 7/11] ACPI / hotplug / PCI: Drop crit

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Date:	Mon, 27 Jan 2014 01:42:47 +0100
From:	"Rafael J. Wysocki" <rjw@...ysocki.net>
To:	ACPI Devel Maling List <linux-acpi@...r.kernel.org>
Cc:	Bjorn Helgaas <bhelgaas@...gle.com>, Aaron Lu <aaron.lu@...el.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: [PATCH 7/11] ACPI / hotplug / PCI: Drop crit_sect locking

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

After recent PCI core changes related to the rescan/remove locking,
the code sections under crit_sect mutexes from ACPIPHP slot objects
are always executed under the general PCI rescan/remove lock.
For this reason, the crit_sect mutexes are simply redundant, so drop
them.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
---
 drivers/pci/hotplug/acpiphp.h      |    1 -
 drivers/pci/hotplug/acpiphp_glue.c |   23 +++--------------------
 2 files changed, 3 insertions(+), 21 deletions(-)

Index: linux-pm/drivers/pci/hotplug/acpiphp_glue.c
===================================================================
--- linux-pm.orig/drivers/pci/hotplug/acpiphp_glue.c
+++ linux-pm/drivers/pci/hotplug/acpiphp_glue.c
@@ -328,7 +328,6 @@ static acpi_status register_slot(acpi_ha
 	slot->bus = bridge->pci_bus;
 	slot->device = device;
 	INIT_LIST_HEAD(&slot->funcs);
-	mutex_init(&slot->crit_sect);
 
 	list_add_tail(&slot->node, &bridge->slots);
 
@@ -741,7 +740,6 @@ static void acpiphp_check_bridge(struct
 		struct pci_bus *bus = slot->bus;
 		struct pci_dev *dev, *tmp;
 
-		mutex_lock(&slot->crit_sect);
 		if (slot_no_hotplug(slot)) {
 			; /* do nothing */
 		} else if (get_slot_status(slot) == ACPI_STA_ALL) {
@@ -756,7 +754,6 @@ static void acpiphp_check_bridge(struct
 		} else {
 			disable_slot(slot);
 		}
-		mutex_unlock(&slot->crit_sect);
 	}
 }
 
@@ -838,12 +835,8 @@ static void hotplug_event(acpi_handle ha
 		} else {
 			struct acpiphp_slot *slot = func->slot;
 
-			if (slot->flags & SLOT_IS_GOING_AWAY)
-				break;
-
-			mutex_lock(&slot->crit_sect);
-			enable_slot(slot);
-			mutex_unlock(&slot->crit_sect);
+			if (!(slot->flags & SLOT_IS_GOING_AWAY))
+				enable_slot(slot);
 		}
 		break;
 
@@ -854,7 +847,6 @@ static void hotplug_event(acpi_handle ha
 			acpiphp_check_bridge(bridge);
 		} else {
 			struct acpiphp_slot *slot = func->slot;
-			int ret;
 
 			if (slot->flags & SLOT_IS_GOING_AWAY)
 				break;
@@ -863,10 +855,7 @@ static void hotplug_event(acpi_handle ha
 			 * Check if anything has changed in the slot and rescan
 			 * from the parent if that's the case.
 			 */
-			mutex_lock(&slot->crit_sect);
-			ret = acpiphp_rescan_slot(slot);
-			mutex_unlock(&slot->crit_sect);
-			if (ret)
+			if (acpiphp_rescan_slot(slot))
 				acpiphp_check_bridge(func->parent);
 		}
 		break;
@@ -1073,13 +1062,10 @@ int acpiphp_enable_slot(struct acpiphp_s
 	if (slot->flags & SLOT_IS_GOING_AWAY)
 		return -ENODEV;
 
-	mutex_lock(&slot->crit_sect);
 	/* configure all functions */
 	if (!(slot->flags & SLOT_ENABLED))
 		enable_slot(slot);
 
-	mutex_unlock(&slot->crit_sect);
-
 	pci_unlock_rescan_remove();
 	return 0;
 }
@@ -1095,8 +1081,6 @@ static int acpiphp_disable_and_eject_slo
 	if (slot->flags & SLOT_IS_GOING_AWAY)
 		return -ENODEV;
 
-	mutex_lock(&slot->crit_sect);
-
 	/* unconfigure all functions */
 	disable_slot(slot);
 
@@ -1110,7 +1094,6 @@ static int acpiphp_disable_and_eject_slo
 			break;
 		}
 
-	mutex_unlock(&slot->crit_sect);
 	return 0;
 }
 
Index: linux-pm/drivers/pci/hotplug/acpiphp.h
===================================================================
--- linux-pm.orig/drivers/pci/hotplug/acpiphp.h
+++ linux-pm/drivers/pci/hotplug/acpiphp.h
@@ -93,7 +93,6 @@ struct acpiphp_slot {
 	struct list_head funcs;		/* one slot may have different
 					   objects (i.e. for each function) */
 	struct slot *slot;
-	struct mutex crit_sect;
 
 	u8		device;		/* pci device# */
 	u32		flags;		/* see below */

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