RE: [PATCH v4 8/8] pciehp: Introduce hotplug_lock to serialize HPevents
From: Rajat Jain
Date: Wed Feb 05 2014 - 15:34:59 EST
Hello,
I found that while fixing the conflicts during rebasing, an "unused variable 'ret' " warning has crept up in this particular patch.
Apologies for the same. I will take care of that, however, am waiting for any additional comments before resending.
Thanks & Best Regards,
Rajat
> -----Original Message-----
> From: Rajat Jain [mailto:rajatxjain@xxxxxxxxx]
> Sent: Tuesday, February 04, 2014 6:31 PM
> To: Bjorn Helgaas; Rafael J. Wysocki; Kenji Kaneshige; Alex Williamson;
> Yijing Wang; linux-pci@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> Yinghai Lu
> Cc: Guenter Roeck; Rajat Jain; Rajat Jain
> Subject: [PATCH v4 8/8] pciehp: Introduce hotplug_lock to serialize HP
> events
>
> 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@xxxxxxxxx>
> Signed-off-by: Rajat Jain <rajatjain@xxxxxxxxxxx>
> Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxx>
> ---
> drivers/pci/hotplug/pciehp.h | 1 +
> drivers/pci/hotplug/pciehp_core.c | 7 ++++++-
> drivers/pci/hotplug/pciehp_ctrl.c | 14 +++++++++++++-
> drivers/pci/hotplug/pciehp_hpc.c | 1 +
> 4 files changed, 21 insertions(+), 2 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..1f2716c 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);
> @@ -310,8 +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);
> + mutex_lock(&p_slot->hotplug_lock);
> if (pciehp_enable_slot(p_slot))
> pciehp_green_led_off(p_slot);
> + mutex_unlock(&p_slot->hotplug_lock);
> mutex_lock(&p_slot->lock);
> p_slot->state = STATIC_STATE;
> mutex_unlock(&p_slot->lock);
> @@ -546,6 +551,9 @@ 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 +592,9 @@ 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 +627,9 @@ 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 6433e73..da4b020 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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