Commit 46cb7b1b authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

PCI: Remove unused SR-IOV VF Migration support 

This reverts commit 74bb1bcc ("PCI: handle SR-IOV Virtual Function
Migration"), removing this exported interface:

  pci_sriov_migration()

Since pci_sriov_migration() is unused, it is impossible to schedule
sriov_migration_task() or use any of the other migration infrastructure.

This is based on Stephen Hemminger's patch (see link below), but goes a bit
further.

Link: http://lkml.kernel.org/r/20131227132710.7190647c@nehalam.linuxnetplumber.net


Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
CC: Stephen Hemminger <stephen@networkplumber.org>
parent 4b180d97

Documentation/PCI/pci-iov-howto.txt

+0 −4
Original line number Diff line number Diff line
@@ -68,10 +68,6 @@ To disable SR-IOV capability: 
	echo  0 > \

        /sys/bus/pci/devices/<DOMAIN:BUS:DEVICE.FUNCTION>/sriov_numvfs



To notify SR-IOV core of Virtual Function Migration:

(a) In the driver:

	irqreturn_t pci_sriov_migration(struct pci_dev *dev);



3.2 Usage example



Following piece of code illustrates the usage of the SR-IOV API.

drivers/pci/iov.c

+0 −119
Original line number Diff line number Diff line
@@ -170,97 +170,6 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset) 
	pci_dev_put(dev);

}



static int sriov_migration(struct pci_dev *dev)

{

	u16 status;

	struct pci_sriov *iov = dev->sriov;



	if (!iov->num_VFs)

		return 0;



	if (!(iov->cap & PCI_SRIOV_CAP_VFM))

		return 0;



	pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);

	if (!(status & PCI_SRIOV_STATUS_VFM))

		return 0;



	schedule_work(&iov->mtask);



	return 1;

}



static void sriov_migration_task(struct work_struct *work)

{

	int i;

	u8 state;

	u16 status;

	struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);



	for (i = iov->initial_VFs; i < iov->num_VFs; i++) {

		state = readb(iov->mstate + i);

		if (state == PCI_SRIOV_VFM_MI) {

			writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);

			state = readb(iov->mstate + i);

			if (state == PCI_SRIOV_VFM_AV)

				virtfn_add(iov->self, i, 1);

		} else if (state == PCI_SRIOV_VFM_MO) {

			virtfn_remove(iov->self, i, 1);

			writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);

			state = readb(iov->mstate + i);

			if (state == PCI_SRIOV_VFM_AV)

				virtfn_add(iov->self, i, 0);

		}

	}



	pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);

	status &= ~PCI_SRIOV_STATUS_VFM;

	pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);

}



static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)

{

	int bir;

	u32 table;

	resource_size_t pa;

	struct pci_sriov *iov = dev->sriov;



	if (nr_virtfn <= iov->initial_VFs)

		return 0;



	pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);

	bir = PCI_SRIOV_VFM_BIR(table);

	if (bir > PCI_STD_RESOURCE_END)

		return -EIO;



	table = PCI_SRIOV_VFM_OFFSET(table);

	if (table + nr_virtfn > pci_resource_len(dev, bir))

		return -EIO;



	pa = pci_resource_start(dev, bir) + table;

	iov->mstate = ioremap(pa, nr_virtfn);

	if (!iov->mstate)

		return -ENOMEM;



	INIT_WORK(&iov->mtask, sriov_migration_task);



	iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;

	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);



	return 0;

}



static void sriov_disable_migration(struct pci_dev *dev)

{

	struct pci_sriov *iov = dev->sriov;



	iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);

	pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);



	cancel_work_sync(&iov->mtask);

	iounmap(iov->mstate);

}



static int sriov_enable(struct pci_dev *dev, int nr_virtfn)

{

	int rc;
@@ -351,12 +260,6 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn) 
			goto failed;

	}



	if (iov->cap & PCI_SRIOV_CAP_VFM) {

		rc = sriov_enable_migration(dev, nr_virtfn);

		if (rc)

			goto failed;

	}



	kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);

	iov->num_VFs = nr_virtfn;
@@ -387,9 +290,6 @@ static void sriov_disable(struct pci_dev *dev) 
	if (!iov->num_VFs)

		return;



	if (iov->cap & PCI_SRIOV_CAP_VFM)

		sriov_disable_migration(dev);



	for (i = 0; i < iov->num_VFs; i++)

		virtfn_remove(dev, i, 0);
@@ -687,25 +587,6 @@ void pci_disable_sriov(struct pci_dev *dev) 
}

EXPORT_SYMBOL_GPL(pci_disable_sriov);



/**

 * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration

 * @dev: the PCI device

 *

 * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.

 *

 * Physical Function driver is responsible to register IRQ handler using

 * VF Migration Interrupt Message Number, and call this function when the

 * interrupt is generated by the hardware.

 */

irqreturn_t pci_sriov_migration(struct pci_dev *dev)

{

	if (!dev->is_physfn)

		return IRQ_NONE;



	return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;

}

EXPORT_SYMBOL_GPL(pci_sriov_migration);



/**

 * pci_num_vf - return number of VFs associated with a PF device_release_driver

 * @dev: the PCI device

drivers/pci/pci.h

+0 −4
Original line number Diff line number Diff line 
#ifndef DRIVERS_PCI_H

#define DRIVERS_PCI_H



#include <linux/workqueue.h>



#define PCI_CFG_SPACE_SIZE	256

#define PCI_CFG_SPACE_EXP_SIZE	4096
@@ -240,8 +238,6 @@ struct pci_sriov { 
	struct pci_dev *dev;	/* lowest numbered PF */

	struct pci_dev *self;	/* this PF */

	struct mutex lock;	/* lock for VF bus */

	struct work_struct mtask; /* VF Migration task */

	u8 __iomem *mstate;	/* VF Migration State Array */

};



#ifdef CONFIG_PCI_ATS

include/linux/pci.h

+0 −4
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ 
#include <linux/atomic.h>

#include <linux/device.h>

#include <linux/io.h>

#include <linux/irqreturn.h>

#include <uapi/linux/pci.h>



#include <linux/pci_ids.h>
@@ -1577,7 +1576,6 @@ void __iomem *pci_ioremap_bar(struct pci_dev *pdev, int bar); 
#ifdef CONFIG_PCI_IOV

int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn);

void pci_disable_sriov(struct pci_dev *dev);

irqreturn_t pci_sriov_migration(struct pci_dev *dev);

int pci_num_vf(struct pci_dev *dev);

int pci_vfs_assigned(struct pci_dev *dev);

int pci_sriov_set_totalvfs(struct pci_dev *dev, u16 numvfs);
@@ -1586,8 +1584,6 @@ int pci_sriov_get_totalvfs(struct pci_dev *dev); 
static inline int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)

{ return -ENODEV; }

static inline void pci_disable_sriov(struct pci_dev *dev) { }

static inline irqreturn_t pci_sriov_migration(struct pci_dev *dev)

{ return IRQ_NONE; }

static inline int pci_num_vf(struct pci_dev *dev) { return 0; }

static inline int pci_vfs_assigned(struct pci_dev *dev)

{ return 0; }

CRA Git | Maintained and supported by SUSTech CRA and CCSE