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Message-ID: <52F9896D.7090908@gmail.com>
Date: Mon, 10 Feb 2014 18:22:37 -0800
From: Rajat Jain <rajatxjain@...il.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>
CC: Rajat Jain <rajatjain@...iper.net>,
"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
Alex Williamson <alex.williamson@...hat.com>,
Yijing Wang <wangyijing@...wei.com>,
"linux-pci@...r.kernel.org" <linux-pci@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Yinghai Lu <yhlu.kernel@...il.com>,
Guenter Roeck <groeck@...iper.net>
Subject: [PATCH v5 8/8] Allow Link state changes for Hot-Plug
Today it is there is no protection around pciehp_enable_slot() and
pciehp_disable_slot() to ensure that they complete before another
hot-plug operation can be done on that particular slot.
This patch introduces the slot->hotplug_lock to ensure that any
hotplug operations (add / remove) complete before another HP event
can begin processing on that particular slot.
Signed-off-by: Rajat Jain <rajatxjain@...il.com>
Signed-off-by: Rajat Jain <rajatjain@...iper.net>
Signed-off-by: Guenter Roeck <groeck@...iper.net>
---
Hello Bjorn,
>
> I applied these to pci/pciehp for v3.15, thanks! I dropped the "ret" decl
> in 8/8, which I assume was the cause of the unused variable warning.
>
Thank you so much for accepting the patchset. The "ret" variable in 8/8
was supposed to be used for holding the return value, so that the call to
pciehp_green_led_off() could be moved to after releasing the lock. Here
is the revised 8/8 patch (only a couple lines diff from v4). Please feel
free to either use this, or just make that small change in
pciehp_power_thread(). I was holding off sending this in case there were
any other comments.
Thank you so much once again,
Rajat
v5: Remove the "unused variable" warning by using it to hold return value
(Thus reducing lock hold time, by moving pciehp_green_led_off() to
after releasing the lock)
v4: same as v3, only rebased on top of 3.14-rc1
v3: same as v2, only patch numbering changed from [4/4] to [8/8].
v2: Same as v1, dropped the "RFC" from subject, added Guenter's signature
v1: Initial patch
drivers/pci/hotplug/pciehp.h | 1 +
drivers/pci/hotplug/pciehp_core.c | 7 ++++++-
drivers/pci/hotplug/pciehp_ctrl.c | 17 +++++++++++++++--
drivers/pci/hotplug/pciehp_hpc.c | 1 +
4 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index d8d0336..8a66866 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -76,6 +76,7 @@ struct slot {
struct hotplug_slot *hotplug_slot;
struct delayed_work work; /* work for button event */
struct mutex lock;
+ struct mutex hotplug_lock;
struct workqueue_struct *wq;
};
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index 53b58de..23b4bde 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -283,8 +283,11 @@ static int pciehp_probe(struct pcie_device *dev)
slot = ctrl->slot;
pciehp_get_adapter_status(slot, &occupied);
pciehp_get_power_status(slot, &poweron);
- if (occupied && pciehp_force)
+ if (occupied && pciehp_force) {
+ mutex_lock(&slot->hotplug_lock);
pciehp_enable_slot(slot);
+ mutex_unlock(&slot->hotplug_lock);
+ }
/* If empty slot's power status is on, turn power off */
if (!occupied && poweron && POWER_CTRL(ctrl))
pciehp_power_off_slot(slot);
@@ -328,10 +331,12 @@ static int pciehp_resume (struct pcie_device *dev)
/* Check if slot is occupied */
pciehp_get_adapter_status(slot, &status);
+ mutex_lock(&slot->hotplug_lock);
if (status)
pciehp_enable_slot(slot);
else
pciehp_disable_slot(slot);
+ mutex_unlock(&slot->hotplug_lock);
return 0;
}
#endif /* PM */
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index 3e40ec0..fec99a1 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -293,6 +293,7 @@ static void pciehp_power_thread(struct work_struct *work)
struct power_work_info *info =
container_of(work, struct power_work_info, work);
struct slot *p_slot = info->p_slot;
+ int ret;
switch (info->req) {
case DISABLE_REQ:
@@ -300,7 +301,9 @@ static void pciehp_power_thread(struct work_struct *work)
"Disabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
+ mutex_lock(&p_slot->hotplug_lock);
pciehp_disable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
mutex_unlock(&p_slot->lock);
@@ -310,7 +313,10 @@ static void pciehp_power_thread(struct work_struct *work)
"Enabling domain:bus:device=%04x:%02x:00\n",
pci_domain_nr(p_slot->ctrl->pcie->port->subordinate),
p_slot->ctrl->pcie->port->subordinate->number);
- if (pciehp_enable_slot(p_slot))
+ mutex_lock(&p_slot->hotplug_lock);
+ ret = pciehp_enable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
+ if (ret)
pciehp_green_led_off(p_slot);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
@@ -546,6 +552,9 @@ static void interrupt_event_handler(struct work_struct *work)
kfree(info);
}
+/*
+ * Note: This function must be called with slot->hotplug_lock held
+ */
int pciehp_enable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
@@ -584,7 +593,9 @@ int pciehp_enable_slot(struct slot *p_slot)
return rc;
}
-
+/*
+ * Note: This function must be called with slot->hotplug_lock held
+ */
int pciehp_disable_slot(struct slot *p_slot)
{
u8 getstatus = 0;
@@ -617,7 +628,9 @@ int pciehp_sysfs_enable_slot(struct slot *p_slot)
case STATIC_STATE:
p_slot->state = POWERON_STATE;
mutex_unlock(&p_slot->lock);
+ mutex_lock(&p_slot->hotplug_lock);
retval = pciehp_enable_slot(p_slot);
+ mutex_unlock(&p_slot->hotplug_lock);
mutex_lock(&p_slot->lock);
p_slot->state = STATIC_STATE;
break;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 55cc389..68447a1 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -686,6 +686,7 @@ static int pcie_init_slot(struct controller *ctrl)
slot->ctrl = ctrl;
mutex_init(&slot->lock);
+ mutex_init(&slot->hotplug_lock);
INIT_DELAYED_WORK(&slot->work, pciehp_queue_pushbutton_work);
ctrl->slot = slot;
return 0;
--
1.7.9.5
--
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