[PATCH 7/11] ACPI / hotplug / PCI: Drop crit_sect locking

From: Rafael J. Wysocki
Date: Sun Jan 26 2014 - 19:35:19 EST


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

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@xxxxxxxxx>
---
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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