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Date: Mon, 17 Feb 2020 17:44:07 +0530
From: Vidya Sagar <vidyas@...dia.com>
To: Kishon Vijay Abraham I <kishon@...com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Andrew Murray <amurray@...goodpenguin.co.uk>,
Athani Nadeem Ladkhan <nadeem@...ence.com>,
Tom Joseph <tjoseph@...ence.com>
CC: <linux-pci@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 1/5] PCI: endpoint: Use notification chain mechanism to
notify EPC events to EPF
On 2/12/2020 4:55 PM, Kishon Vijay Abraham I wrote:
> External email: Use caution opening links or attachments
>
>
> Use atomic_notifier_call_chain() to notify EPC events like linkup to EPF
> driver instead of using linkup ops in EPF driver. This is in preparation
> for adding proper locking mechanism to EPF ops. This will also enable to
> add more events (in addition to linkup) in the future.
>
> Signed-off-by: Kishon Vijay Abraham I <kishon@...com>
> ---
> drivers/pci/endpoint/functions/pci-epf-test.c | 13 ++++++++---
> drivers/pci/endpoint/pci-epc-core.c | 9 ++------
> drivers/pci/endpoint/pci-epf-core.c | 22 +------------------
> include/linux/pci-epc.h | 8 +++++++
> include/linux/pci-epf.h | 6 ++---
> 5 files changed, 23 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 5d74f81ddfe4..bddff15052cc 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -360,12 +360,16 @@ static void pci_epf_test_cmd_handler(struct work_struct *work)
> msecs_to_jiffies(1));
> }
>
> -static void pci_epf_test_linkup(struct pci_epf *epf)
> +static int pci_epf_test_notifier(struct notifier_block *nb, unsigned long val,
> + void *data)
> {
> + struct pci_epf *epf = container_of(nb, struct pci_epf, nb);
> struct pci_epf_test *epf_test = epf_get_drvdata(epf);
>
> queue_delayed_work(kpcitest_workqueue, &epf_test->cmd_handler,
> msecs_to_jiffies(1));
> +
> + return NOTIFY_OK;
> }
>
> static void pci_epf_test_unbind(struct pci_epf *epf)
> @@ -546,8 +550,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
> }
> }
>
> - if (!linkup_notifier)
> + if (linkup_notifier) {
> + epf->nb.notifier_call = pci_epf_test_notifier;
> + pci_epc_register_notifier(epc, &epf->nb);
> + } else {
> queue_work(kpcitest_workqueue, &epf_test->cmd_handler.work);
> + }
>
> return 0;
> }
> @@ -580,7 +588,6 @@ static int pci_epf_test_probe(struct pci_epf *epf)
> static struct pci_epf_ops ops = {
> .unbind = pci_epf_test_unbind,
> .bind = pci_epf_test_bind,
> - .linkup = pci_epf_test_linkup,
> };
>
> static struct pci_epf_driver test_driver = {
> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
> index 2091508c1620..2f6436599fcb 100644
> --- a/drivers/pci/endpoint/pci-epc-core.c
> +++ b/drivers/pci/endpoint/pci-epc-core.c
> @@ -539,16 +539,10 @@ EXPORT_SYMBOL_GPL(pci_epc_remove_epf);
> */
> void pci_epc_linkup(struct pci_epc *epc)
> {
> - unsigned long flags;
> - struct pci_epf *epf;
> -
> if (!epc || IS_ERR(epc))
> return;
>
> - spin_lock_irqsave(&epc->lock, flags);
> - list_for_each_entry(epf, &epc->pci_epf, list)
> - pci_epf_linkup(epf);
> - spin_unlock_irqrestore(&epc->lock, flags);
> + atomic_notifier_call_chain(&epc->notifier, 0, NULL);
> }
> EXPORT_SYMBOL_GPL(pci_epc_linkup);
>
> @@ -612,6 +606,7 @@ __pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
>
> spin_lock_init(&epc->lock);
> INIT_LIST_HEAD(&epc->pci_epf);
> + ATOMIC_INIT_NOTIFIER_HEAD(&epc->notifier);
>
> device_initialize(&epc->dev);
> epc->dev.class = pci_epc_class;
> diff --git a/drivers/pci/endpoint/pci-epf-core.c b/drivers/pci/endpoint/pci-epf-core.c
> index fb1306de8f40..93f28c65ace0 100644
> --- a/drivers/pci/endpoint/pci-epf-core.c
> +++ b/drivers/pci/endpoint/pci-epf-core.c
> @@ -20,26 +20,6 @@ static DEFINE_MUTEX(pci_epf_mutex);
> static struct bus_type pci_epf_bus_type;
> static const struct device_type pci_epf_type;
>
> -/**
> - * pci_epf_linkup() - Notify the function driver that EPC device has
> - * established a connection with the Root Complex.
> - * @epf: the EPF device bound to the EPC device which has established
> - * the connection with the host
> - *
> - * Invoke to notify the function driver that EPC device has established
> - * a connection with the Root Complex.
> - */
> -void pci_epf_linkup(struct pci_epf *epf)
> -{
> - if (!epf->driver) {
> - dev_WARN(&epf->dev, "epf device not bound to driver\n");
> - return;
> - }
> -
> - epf->driver->ops->linkup(epf);
> -}
> -EXPORT_SYMBOL_GPL(pci_epf_linkup);
> -
> /**
> * pci_epf_unbind() - Notify the function driver that the binding between the
> * EPF device and EPC device has been lost
> @@ -214,7 +194,7 @@ int __pci_epf_register_driver(struct pci_epf_driver *driver,
> if (!driver->ops)
> return -EINVAL;
>
> - if (!driver->ops->bind || !driver->ops->unbind || !driver->ops->linkup)
> + if (!driver->ops->bind || !driver->ops->unbind)
> return -EINVAL;
>
> driver->driver.bus = &pci_epf_bus_type;
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 56f1846b9d39..36644ccd32ac 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -89,6 +89,7 @@ struct pci_epc_mem {
> * @max_functions: max number of functions that can be configured in this EPC
> * @group: configfs group representing the PCI EPC device
> * @lock: spinlock to protect pci_epc ops
> + * @notifier: used to notify EPF of any EPC events (like linkup)
> */
> struct pci_epc {
> struct device dev;
> @@ -99,6 +100,7 @@ struct pci_epc {
> struct config_group *group;
> /* spinlock to protect against concurrent access of EP controller */
> spinlock_t lock;
> + struct atomic_notifier_head notifier;
> };
>
> /**
> @@ -141,6 +143,12 @@ static inline void *epc_get_drvdata(struct pci_epc *epc)
> return dev_get_drvdata(&epc->dev);
> }
>
> +static inline int
> +pci_epc_register_notifier(struct pci_epc *epc, struct notifier_block *nb)
> +{
> + return atomic_notifier_chain_register(&epc->notifier, nb);
> +}
> +
> struct pci_epc *
> __devm_pci_epc_create(struct device *dev, const struct pci_epc_ops *ops,
> struct module *owner);
> diff --git a/include/linux/pci-epf.h b/include/linux/pci-epf.h
> index 2d6f07556682..4993f7f6439b 100644
> --- a/include/linux/pci-epf.h
> +++ b/include/linux/pci-epf.h
> @@ -55,13 +55,10 @@ struct pci_epf_header {
> * @bind: ops to perform when a EPC device has been bound to EPF device
> * @unbind: ops to perform when a binding has been lost between a EPC device
> * and EPF device
> - * @linkup: ops to perform when the EPC device has established a connection with
> - * a host system
> */
> struct pci_epf_ops {
> int (*bind)(struct pci_epf *epf);
> void (*unbind)(struct pci_epf *epf);
> - void (*linkup)(struct pci_epf *epf);
> };
>
> /**
> @@ -112,6 +109,7 @@ struct pci_epf_bar {
> * @epc: the EPC device to which this EPF device is bound
> * @driver: the EPF driver to which this EPF device is bound
> * @list: to add pci_epf as a list of PCI endpoint functions to pci_epc
> + * @nb: notifier block to notify EPF of any EPC events (like linkup)
> */
> struct pci_epf {
> struct device dev;
> @@ -125,6 +123,7 @@ struct pci_epf {
> struct pci_epc *epc;
> struct pci_epf_driver *driver;
> struct list_head list;
> + struct notifier_block nb;
> };
>
> #define to_pci_epf(epf_dev) container_of((epf_dev), struct pci_epf, dev)
> @@ -154,5 +153,4 @@ void *pci_epf_alloc_space(struct pci_epf *epf, size_t size, enum pci_barno bar,
> void pci_epf_free_space(struct pci_epf *epf, void *addr, enum pci_barno bar);
> int pci_epf_bind(struct pci_epf *epf);
> void pci_epf_unbind(struct pci_epf *epf);
> -void pci_epf_linkup(struct pci_epf *epf);
> #endif /* __LINUX_PCI_EPF_H */
> --
> 2.17.1
>
Tested with the help of series @
http://patchwork.ozlabs.org/project/linux-pci/list/?series=158959
Tested-by: Vidya Sagar <vidyas@...dia.com>
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