Date:   Wed, 18 Jan 2017 12:11:40 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     Selvin Xavier <selvin.xavier@...adcom.com>
Cc:     dledford@...hat.com, linux-rdma@...r.kernel.org,
        netdev@...r.kernel.org, michael.chan@...adcom.com,
        Eddie Wai <eddie.wai@...adcom.com>,
        Devesh Sharma <devesh.sharma@...adcom.com>,
        Somnath Kotur <somnath.kotur@...adcom.com>,
        Sriharsha Basavapatna <sriharsha.basavapatna@...adcom.com>
Subject: Re: [PATCH for bnxt_re V4 03/21] RDMA/bnxt_re: register with the NIC
 driver

On Wed, Dec 21, 2016 at 03:41:52AM -0800, Selvin Xavier wrote:
> This patch handles the registration with the bnxt_en driver.
> The bnxt_re driver first registers with netdev notifier chain and upon
> receiving the NETDEV_REGISTER event, it registers with bnxt_en driver.
>
> 	1. bnxt_en's ulp_probe function returns a structure that contains
> 	   information 	about the device and additional entry points.
> 	2. bnxt_en driver returns 'struct bnxt_eth_dev' that contains set
> 	   of operation  vectors that bnxt_re driver invokes later.
> 	3. bnxt_request_msix() allows the bnxt_re driver to specify the
> 	   number of MSI-X vectors that are needed.
> 	4. bnxt_send_fw_msg () is used to send messages to the FW
> 	5. bnxt_register_async_events() is used to register for async
> 	   event callbacks.
>
> v2: Remove some sparse warning. Also, remove some unused code from unreg
>     path.
> v3: Removed condition checks for rdev reported during static code analysis.
>     Check the return value of try_module_get while getting bnxt_en
>     reference.
>
> Signed-off-by: Eddie Wai <eddie.wai@...adcom.com>
> Signed-off-by: Devesh Sharma <devesh.sharma@...adcom.com>
> Signed-off-by: Somnath Kotur <somnath.kotur@...adcom.com>
> Signed-off-by: Sriharsha Basavapatna <sriharsha.basavapatna@...adcom.com>
> Signed-off-by: Selvin Xavier <selvin.xavier@...adcom.com>
> ---
>  drivers/infiniband/hw/bnxt_re/bnxt_re.h |  51 ++++
>  drivers/infiniband/hw/bnxt_re/main.c    | 448 ++++++++++++++++++++++++++++++++
>  2 files changed, 499 insertions(+)
>
> diff --git a/drivers/infiniband/hw/bnxt_re/bnxt_re.h b/drivers/infiniband/hw/bnxt_re/bnxt_re.h
> index f9b8542..8b73e3d 100644
> --- a/drivers/infiniband/hw/bnxt_re/bnxt_re.h
> +++ b/drivers/infiniband/hw/bnxt_re/bnxt_re.h
> @@ -42,5 +42,56 @@
>  #define ROCE_DRV_MODULE_NAME		"bnxt_re"
>  #define ROCE_DRV_MODULE_VERSION		"1.0.0"
>
> +#define BNXT_RE_REF_WAIT_COUNT		10
>  #define BNXT_RE_DESC	"Broadcom NetXtreme-C/E RoCE Driver"
> +
> +struct bnxt_re_work {
> +	struct work_struct	work;
> +	unsigned long		event;
> +	struct bnxt_re_dev      *rdev;
> +	struct net_device	*vlan_dev;
> +};
> +
> +#define BNXT_RE_MIN_MSIX		2
> +#define BNXT_RE_MAX_MSIX		16
> +struct bnxt_re_dev {
> +	struct ib_device		ibdev;
> +	struct list_head		list;
> +	atomic_t			ref_count;
> +	unsigned long			flags;
> +#define BNXT_RE_FLAG_NETDEV_REGISTERED	0
> +#define BNXT_RE_FLAG_IBDEV_REGISTERED	1
> +#define BNXT_RE_FLAG_GOT_MSIX		2
> +#define BNXT_RE_FLAG_RCFW_CHANNEL_EN	8
> +#define BNXT_RE_FLAG_QOS_WORK_REG	16
> +	struct net_device		*netdev;
> +	unsigned int			version, major, minor;
> +	struct bnxt_en_dev		*en_dev;
> +	struct bnxt_msix_entry		msix_entries[BNXT_RE_MAX_MSIX];
> +	int				num_msix;
> +
> +	int				id;
> +
> +	atomic_t			qp_count;
> +	struct mutex			qp_lock;	/* protect qp list */
> +	struct list_head		qp_list;
> +
> +	atomic_t			cq_count;
> +	atomic_t			srq_count;
> +	atomic_t			mr_count;
> +	atomic_t			mw_count;
> +	/* Max of 2 lossless traffic class supported per port */
> +	u16				cosq[2];
> +};
> +
> +#define to_bnxt_re_dev(ptr, member)	\
> +	container_of((ptr), struct bnxt_re_dev, member)
> +
> +static inline struct device *rdev_to_dev(struct bnxt_re_dev *rdev)
> +{
> +	if (rdev)
> +		return  &rdev->ibdev.dev;
> +	return NULL;
> +}
> +
>  #endif
> diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c
> index 6c22d51..71d7501 100644
> --- a/drivers/infiniband/hw/bnxt_re/main.c
> +++ b/drivers/infiniband/hw/bnxt_re/main.c
> @@ -38,10 +38,24 @@
>
>  #include <linux/module.h>
>  #include <linux/netdevice.h>
> +#include <linux/ethtool.h>
>  #include <linux/mutex.h>
>  #include <linux/list.h>
>  #include <linux/rculist.h>
> +#include <linux/spinlock.h>
> +#include <linux/pci.h>
> +#include <net/ipv6.h>
> +#include <net/addrconf.h>
> +
> +#include <rdma/ib_verbs.h>
> +#include <rdma/ib_user_verbs.h>
> +#include <rdma/ib_umem.h>
> +#include <rdma/ib_addr.h>
> +
> +#include "bnxt_ulp.h"
> +#include "roce_hsi.h"
>  #include "bnxt_re.h"
> +#include "bnxt.h"
>  static char version[] =
>  		BNXT_RE_DESC " v" ROCE_DRV_MODULE_VERSION "\n";
>
> @@ -55,6 +69,384 @@ static struct list_head bnxt_re_dev_list = LIST_HEAD_INIT(bnxt_re_dev_list);
>  /* Mutex to protect the list of bnxt_re devices added */
>  static DEFINE_MUTEX(bnxt_re_dev_lock);
>  static struct workqueue_struct *bnxt_re_wq;
> +
> +/* for handling bnxt_en callbacks later */
> +static void bnxt_re_stop(void *p)
> +{
> +}
> +
> +static void bnxt_re_start(void *p)
> +{
> +}
> +
> +static void bnxt_re_sriov_config(void *p, int num_vfs)
> +{
> +}
> +
> +static struct bnxt_ulp_ops bnxt_re_ulp_ops = {
> +	.ulp_async_notifier = NULL,
> +	.ulp_stop = bnxt_re_stop,
> +	.ulp_start = bnxt_re_start,
> +	.ulp_sriov_config = bnxt_re_sriov_config
> +};
> +
> +/* The rdev ref_count is to protect immature removal of the device */
> +static inline void bnxt_re_hold(struct bnxt_re_dev *rdev)
> +{
> +	atomic_inc(&rdev->ref_count);
> +}
> +
> +static inline void bnxt_re_put(struct bnxt_re_dev *rdev)
> +{
> +	atomic_dec(&rdev->ref_count);
> +}
> +
> +/* RoCE -> Net driver */
> +
> +/* Driver registration routines used to let the networking driver (bnxt_en)
> + * to know that the RoCE driver is now installed
> + */
> +static int bnxt_re_unregister_netdev(struct bnxt_re_dev *rdev, bool lock_wait)
> +{
> +	struct bnxt_en_dev *en_dev;
> +	int rc;
> +
> +	if (!rdev)
> +		return -EINVAL;
> +
> +	en_dev = rdev->en_dev;
> +	/* Acquire rtnl lock if it is not invokded from netdev event */
> +	if (lock_wait)
> +		rtnl_lock();
> +
> +	rc = en_dev->en_ops->bnxt_unregister_device(rdev->en_dev,
> +						    BNXT_ROCE_ULP);
> +	if (lock_wait)
> +		rtnl_unlock();
> +	return rc;
> +}
> +
> +static int bnxt_re_register_netdev(struct bnxt_re_dev *rdev)
> +{
> +	struct bnxt_en_dev *en_dev;
> +	int rc = 0;
> +
> +	if (!rdev)
> +		return -EINVAL;
> +
> +	en_dev = rdev->en_dev;
> +
> +	rtnl_lock();
> +	rc = en_dev->en_ops->bnxt_register_device(en_dev, BNXT_ROCE_ULP,
> +						  &bnxt_re_ulp_ops, rdev);
> +	rtnl_unlock();
> +	return rc;
> +}
> +
> +static int bnxt_re_free_msix(struct bnxt_re_dev *rdev, bool lock_wait)
> +{
> +	struct bnxt_en_dev *en_dev;
> +	int rc;
> +
> +	if (!rdev)
> +		return -EINVAL;
> +
> +	en_dev = rdev->en_dev;
> +
> +	if (lock_wait)
> +		rtnl_lock();
> +
> +	rc = en_dev->en_ops->bnxt_free_msix(rdev->en_dev, BNXT_ROCE_ULP);
> +
> +	if (lock_wait)
> +		rtnl_unlock();
> +	return rc;
> +}
> +
> +static int bnxt_re_request_msix(struct bnxt_re_dev *rdev)
> +{
> +	int rc = 0, num_msix_want = BNXT_RE_MIN_MSIX, num_msix_got;
> +	struct bnxt_en_dev *en_dev;
> +
> +	if (!rdev)
> +		return -EINVAL;
> +
> +	en_dev = rdev->en_dev;
> +
> +	rtnl_lock();
> +	num_msix_got = en_dev->en_ops->bnxt_request_msix(en_dev, BNXT_ROCE_ULP,
> +							 rdev->msix_entries,
> +							 num_msix_want);
> +	if (num_msix_got < BNXT_RE_MIN_MSIX) {
> +		rc = -EINVAL;
> +		goto done;
> +	}
> +	if (num_msix_got != num_msix_want) {
> +		dev_warn(rdev_to_dev(rdev),
> +			 "Requested %d MSI-X vectors, got %d\n",
> +			 num_msix_want, num_msix_got);
> +	}
> +	rdev->num_msix = num_msix_got;
> +done:
> +	rtnl_unlock();
> +	return rc;
> +}
> +
> +/* Device */
> +
> +static bool is_bnxt_re_dev(struct net_device *netdev)
> +{
> +	struct ethtool_drvinfo drvinfo;
> +
> +	if (netdev->ethtool_ops && netdev->ethtool_ops->get_drvinfo) {
> +		memset(&drvinfo, 0, sizeof(drvinfo));
> +		netdev->ethtool_ops->get_drvinfo(netdev, &drvinfo);
> +
> +		if (strcmp(drvinfo.driver, "bnxt_en"))
> +			return false;
> +		return true;
> +	}
> +	return false;
> +}
> +
> +static struct bnxt_re_dev *bnxt_re_from_netdev(struct net_device *netdev)
> +{
> +	struct bnxt_re_dev *rdev;
> +
> +	rcu_read_lock();
> +	list_for_each_entry_rcu(rdev, &bnxt_re_dev_list, list) {
> +		if (rdev->netdev == netdev) {
> +			rcu_read_unlock();
> +			return rdev;
> +		}
> +	}
> +	rcu_read_unlock();
> +	return NULL;
> +}
> +
> +static void bnxt_re_dev_unprobe(struct net_device *netdev,
> +				struct bnxt_en_dev *en_dev)
> +{
> +	dev_put(netdev);
> +	module_put(en_dev->pdev->driver->driver.owner);
> +}
> +
> +static struct bnxt_en_dev *bnxt_re_dev_probe(struct net_device *netdev)
> +{
> +	struct bnxt *bp = netdev_priv(netdev);
> +	struct bnxt_en_dev *en_dev;
> +	struct pci_dev *pdev;
> +
> +	/* Call bnxt_en's RoCE probe via indirect API */
> +	if (!bp->ulp_probe)
> +		return ERR_PTR(-EINVAL);
> +
> +	en_dev = bp->ulp_probe(netdev);
> +	if (IS_ERR(en_dev))
> +		return en_dev;
> +
> +	pdev = en_dev->pdev;
> +	if (!pdev)
> +		return ERR_PTR(-EINVAL);
> +
> +	/* Bump net device reference count */
> +	if (!try_module_get(pdev->driver->driver.owner))
> +		return ERR_PTR(-ENODEV);
> +
> +	dev_hold(netdev);
> +
> +	return en_dev;
> +}
> +
> +static void bnxt_re_dev_remove(struct bnxt_re_dev *rdev)
> +{
> +	int i = BNXT_RE_REF_WAIT_COUNT;
> +
> +	/* Wait for rdev refcount to come down */
> +	while ((atomic_read(&rdev->ref_count) > 1) && i--)
> +		msleep(100);
> +
> +	if (atomic_read(&rdev->ref_count) > 1)
> +		dev_err(rdev_to_dev(rdev),
> +			"Failed waiting for ref count to deplete %d",
> +			atomic_read(&rdev->ref_count));
> +
> +	atomic_set(&rdev->ref_count, 0);
> +	dev_put(rdev->netdev);
> +	rdev->netdev = NULL;
> +
> +	mutex_lock(&bnxt_re_dev_lock);
> +	list_del_rcu(&rdev->list);
> +	mutex_unlock(&bnxt_re_dev_lock);
> +
> +	synchronize_rcu();
> +	flush_workqueue(bnxt_re_wq);
> +
> +	ib_dealloc_device(&rdev->ibdev);
> +	/* rdev is gone */
> +}
> +
> +static struct bnxt_re_dev *bnxt_re_dev_add(struct net_device *netdev,
> +					   struct bnxt_en_dev *en_dev)
> +{
> +	struct bnxt_re_dev *rdev;
> +
> +	/* Allocate bnxt_re_dev instance here */
> +	rdev = (struct bnxt_re_dev *)ib_alloc_device(sizeof(*rdev));
> +	if (!rdev) {
> +		dev_err(NULL, "%s: bnxt_re_dev allocation failure!",
> +			ROCE_DRV_MODULE_NAME);
> +		return NULL;
> +	}
> +	/* Default values */
> +	atomic_set(&rdev->ref_count, 0);
> +	rdev->netdev = netdev;
> +	dev_hold(rdev->netdev);
> +	rdev->en_dev = en_dev;
> +	rdev->id = rdev->en_dev->pdev->devfn;
> +	INIT_LIST_HEAD(&rdev->qp_list);
> +	mutex_init(&rdev->qp_lock);
> +	atomic_set(&rdev->qp_count, 0);
> +	atomic_set(&rdev->cq_count, 0);
> +	atomic_set(&rdev->srq_count, 0);
> +	atomic_set(&rdev->mr_count, 0);
> +	atomic_set(&rdev->mw_count, 0);
> +	rdev->cosq[0] = 0xFFFF;
> +	rdev->cosq[1] = 0xFFFF;
> +
> +	mutex_lock(&bnxt_re_dev_lock);
> +	list_add_tail_rcu(&rdev->list, &bnxt_re_dev_list);
> +	mutex_unlock(&bnxt_re_dev_lock);
> +	return rdev;
> +}
> +
> +static void bnxt_re_ib_unreg(struct bnxt_re_dev *rdev, bool lock_wait)
> +{
> +	int rc;
> +
> +	if (test_and_clear_bit(BNXT_RE_FLAG_GOT_MSIX, &rdev->flags)) {
> +		rc = bnxt_re_free_msix(rdev, lock_wait);
> +		if (rc)
> +			dev_warn(rdev_to_dev(rdev),
> +				 "Failed to free MSI-X vectors: %#x", rc);
> +	}
> +	if (test_and_clear_bit(BNXT_RE_FLAG_NETDEV_REGISTERED, &rdev->flags)) {
> +		rc = bnxt_re_unregister_netdev(rdev, lock_wait);
> +		if (rc)
> +			dev_warn(rdev_to_dev(rdev),
> +				 "Failed to unregister with netdev: %#x", rc);
> +	}
> +}
> +
> +static int bnxt_re_ib_reg(struct bnxt_re_dev *rdev)
> +{
> +	int i, j, rc;
> +
> +	/* Registered a new RoCE device instance to netdev */
> +	rc = bnxt_re_register_netdev(rdev);
> +	if (rc) {
> +		pr_err("Failed to register with netedev: %#x\n", rc);
> +		return -EINVAL;
> +	}
> +	set_bit(BNXT_RE_FLAG_NETDEV_REGISTERED, &rdev->flags);
> +
> +	rc = bnxt_re_request_msix(rdev);
> +	if (rc) {
> +		pr_err("Failed to get MSI-X vectors: %#x\n", rc);
> +		rc = -EINVAL;
> +		goto fail;
> +	}
> +	set_bit(BNXT_RE_FLAG_GOT_MSIX, &rdev->flags);
> +
> +	return 0;
> +fail:
> +	bnxt_re_ib_unreg(rdev, true);
> +	return rc;
> +}
> +
> +static void bnxt_re_dev_unreg(struct bnxt_re_dev *rdev)
> +{
> +	struct bnxt_en_dev *en_dev = rdev->en_dev;
> +	struct net_device *netdev = rdev->netdev;
> +
> +	bnxt_re_dev_remove(rdev);
> +
> +	if (netdev)
> +		bnxt_re_dev_unprobe(netdev, en_dev);
> +}
> +
> +static int bnxt_re_dev_reg(struct bnxt_re_dev **rdev, struct net_device *netdev)
> +{
> +	struct bnxt_en_dev *en_dev;
> +	int rc = 0;
> +
> +	if (!is_bnxt_re_dev(netdev))
> +		return -ENODEV;
> +
> +	en_dev = bnxt_re_dev_probe(netdev);
> +	if (IS_ERR(en_dev)) {
> +		pr_err("%s: Failed to probe\n", ROCE_DRV_MODULE_NAME);
> +		rc = PTR_ERR(en_dev);
> +		goto exit;
> +	}
> +	*rdev = bnxt_re_dev_add(netdev, en_dev);
> +	if (!*rdev) {
> +		rc = -ENOMEM;
> +		bnxt_re_dev_unprobe(netdev, en_dev);
> +		goto exit;
> +	}
> +	bnxt_re_hold(*rdev);
> +exit:
> +	return rc;
> +}
> +
> +static void bnxt_re_remove_one(struct bnxt_re_dev *rdev)
> +{
> +	pci_dev_put(rdev->en_dev->pdev);
> +}
> +
> +/* Handle all deferred netevents tasks */
> +static void bnxt_re_task(struct work_struct *work)
> +{
> +	struct bnxt_re_work *re_work;
> +	struct bnxt_re_dev *rdev;
> +	int rc = 0;
> +
> +	re_work = container_of(work, struct bnxt_re_work, work);
> +	rdev = re_work->rdev;
> +
> +	if (re_work->event != NETDEV_REGISTER &&
> +	    !test_bit(BNXT_RE_FLAG_IBDEV_REGISTERED, &rdev->flags))
> +		return;
> +
> +	switch (re_work->event) {
> +	case NETDEV_REGISTER:
> +		rc = bnxt_re_ib_reg(rdev);
> +		if (rc)
> +			dev_err(rdev_to_dev(rdev),
> +				"Failed to register with IB: %#x", rc);
> +		break;
> +	case NETDEV_UP:
> +
> +		break;
> +	case NETDEV_DOWN:
> +
> +		break;
> +
> +	case NETDEV_CHANGE:
> +
> +		break;
> +	default:
> +		break;
> +	}

Why do you need empty lines and "break"s between cases?
It can be written as a fallback
case ..:
case ..:
   break;

> +	kfree(re_work);
> +}
> +
> +static void bnxt_re_init_one(struct bnxt_re_dev *rdev)
> +{
> +	pci_dev_get(rdev->en_dev->pdev);
> +}
> +
>  /*
>   * "Notifier chain callback can be invoked for the same chain from
>   * different CPUs at the same time".
> @@ -72,6 +464,62 @@ static struct workqueue_struct *bnxt_re_wq;
>  static int bnxt_re_netdev_event(struct notifier_block *notifier,
>  				unsigned long event, void *ptr)
>  {
> +	struct net_device *real_dev, *netdev = netdev_notifier_info_to_dev(ptr);
> +	struct bnxt_re_work *re_work;
> +	struct bnxt_re_dev *rdev;
> +	int rc = 0;
> +
> +	real_dev = rdma_vlan_dev_real_dev(netdev);
> +	if (!real_dev)
> +		real_dev = netdev;
> +
> +	rdev = bnxt_re_from_netdev(real_dev);
> +	if (!rdev && event != NETDEV_REGISTER)
> +		goto exit;
> +	if (real_dev != netdev)
> +		goto exit;
> +
> +	if (rdev)
> +		bnxt_re_hold(rdev);
> +
> +	switch (event) {
> +	case NETDEV_REGISTER:
> +		if (rdev)
> +			break;
> +		rc = bnxt_re_dev_reg(&rdev, real_dev);
> +		if (rc == -ENODEV)
> +			break;
> +		if (rc) {
> +			pr_err("Failed to register with the device %s: %#x\n",
> +			       real_dev->name, rc);
> +			break;
> +		}
> +		bnxt_re_init_one(rdev);
> +		goto sch_work;
> +
> +	case NETDEV_UNREGISTER:
> +		bnxt_re_ib_unreg(rdev, false);
> +		bnxt_re_remove_one(rdev);
> +		bnxt_re_dev_unreg(rdev);
> +		break;
> +
> +	default:
> +sch_work:

It is very awkward goto label at the middle of switch construction.
Please consider to rewrite it.

> +		/* Allocate for the deferred task */
> +		re_work = kzalloc(sizeof(*re_work), GFP_ATOMIC);
> +		if (!re_work)
> +			break;
> +
> +		re_work->rdev = rdev;
> +		re_work->event = event;
> +		re_work->vlan_dev = (real_dev == netdev ? NULL : netdev);
> +		INIT_WORK(&re_work->work, bnxt_re_task);
> +		queue_work(bnxt_re_wq, &re_work->work);
> +		break;
> +	}
> +	if (rdev)
> +		bnxt_re_put(rdev);
> +exit:
>  	return NOTIFY_DONE;
>  }
>
> --
> 2.5.5
>
> --
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