Commit f8f59847 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'implement-DEVLINK_CMD_REGION_NEW' 

Jacob Keller says:

====================
implement DEVLINK_CMD_REGION_NEW

This series adds support for the DEVLINK_CMD_REGION_NEW operation, used to
enable userspace requesting a snapshot of a region on demand.

This can be useful to enable adding regions for a driver for which there is
no trigger to create snapshots. By making this a core part of devlink, there
is no need for the drivers to use a separate channel such as debugfs.

The primary intent for this kind of region is to expose device information
that might be useful for diagnostics and information gathering.

The first few patches refactor regions to support a new ops structure for
extending the available operations that regions can perform. This includes
converting the destructor into an op from a function argument.

Next, patches refactor the snapshot id allocation to use an xarray which
tracks the number of current snapshots using a given id. This is done so
that id lifetime can be determined, and ids can be released when no longer
in use.

Without this change, snapshot ids remain used forever, until the snapshot_id
count rolled over UINT_MAX.

Finally, code to enable the previously unused DEVLINK_CMD_REGION_NEW is
added. This code enforces that the snapshot id is always provided, unlike
previous revisions of this series.

Finally, a patch is added to enable using this new command via the .snapshot
callback in both netdevsim and the ice driver.

For the ice driver, a new "nvm-flash" region is added, which will enable
read access to the NVM flash contents. The intention for this is to allow
diagnostics tools to gather information about the device. By using a
snapshot and gathering the NVM contents all at once, the contents can be
atomic.

Links to previous discussions:
1st RFC - https://lore.kernel.org/netdev/20200130225913.1671982-1-jacob.e.keller@intel.com/
2nd RFC - https://lore.kernel.org/netdev/20200214232223.3442651-1-jacob.e.keller@intel.com/
v1 - https://lore.kernel.org/netdev/20200324223445.2077900-1-jacob.e.keller@intel.com/
v2 - https://lore.kernel.org/netdev/20200326035157.2211090-1-jacob.e.keller@intel.com/



Major changes since RFC:
* use an xarray for tracking snapshot ids, rather than an IDR
* remove support for auto-generated snapshot ids in DEVLINK_CMD_REGION_NEW

See each patch for an individual changelog per-patch
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 6739ce85 dce730f1

Documentation/networking/devlink/devlink-region.rst

+8 −0
Original line number Diff line number Diff line
@@ -20,6 +20,11 @@ address regions that are otherwise inaccessible to the user. 
Regions may also be used to provide an additional way to debug complex error

states, but see also :doc:`devlink-health`



Regions may optionally support capturing a snapshot on demand via the

``DEVLINK_CMD_REGION_NEW`` netlink message. A driver wishing to allow

requested snapshots must implement the ``.snapshot`` callback for the region

in its ``devlink_region_ops`` structure.



example usage

-------------
@@ -40,6 +45,9 @@ example usage 
    # Delete a snapshot using:

    $ devlink region del pci/0000:00:05.0/cr-space snapshot 1



    # Request an immediate snapshot, if supported by the region

    $ devlink region new pci/0000:00:05.0/cr-space snapshot 5



    # Dump a snapshot:

    $ devlink region dump pci/0000:00:05.0/fw-health snapshot 1

    0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30

Documentation/networking/devlink/ice.rst

+26 −0
Original line number Diff line number Diff line
@@ -69,3 +69,29 @@ The ``ice`` driver reports the following versions 
      - The version of the DDP package that is active in the device. Note

        that both the name (as reported by ``fw.app.name``) and version are

        required to uniquely identify the package.



Regions

=======



The ``ice`` driver enables access to the contents of the Non Volatile Memory

flash chip via the ``nvm-flash`` region.



Users can request an immediate capture of a snapshot via the

``DEVLINK_CMD_REGION_NEW``



.. code:: shell



    $ devlink region new pci/0000:01:00.0/nvm-flash snapshot 1

    $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1



    $ devlink region dump pci/0000:01:00.0/nvm-flash snapshot 1

    0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30

    0000000000000010 0000 0000 ffff ff04 0029 8c00 0028 8cc8

    0000000000000020 0016 0bb8 0016 1720 0000 0000 c00f 3ffc

    0000000000000030 bada cce5 bada cce5 bada cce5 bada cce5



    $ devlink region read pci/0000:01:00.0/nvm-flash snapshot 1 address 0

        length 16

    0000000000000000 0014 95dc 0014 9514 0035 1670 0034 db30



    $ devlink region delete pci/0000:01:00.0/nvm-flash snapshot 1

drivers/net/ethernet/intel/ice/ice.h

+2 −0
Original line number Diff line number Diff line
@@ -351,6 +351,8 @@ struct ice_pf { 
	/* devlink port data */

	struct devlink_port devlink_port;



	struct devlink_region *nvm_region;



	/* OS reserved IRQ details */

	struct msix_entry *msix_entries;

	struct ice_res_tracker *irq_tracker;

drivers/net/ethernet/intel/ice/ice_devlink.c

+96 −0
Original line number Diff line number Diff line
@@ -318,3 +318,99 @@ void ice_devlink_destroy_port(struct ice_pf *pf) 
	devlink_port_type_clear(&pf->devlink_port);

	devlink_port_unregister(&pf->devlink_port);

}



/**

 * ice_devlink_nvm_snapshot - Capture a snapshot of the Shadow RAM contents

 * @devlink: the devlink instance

 * @extack: extended ACK response structure

 * @data: on exit points to snapshot data buffer

 *

 * This function is called in response to the DEVLINK_CMD_REGION_TRIGGER for

 * the shadow-ram devlink region. It captures a snapshot of the shadow ram

 * contents. This snapshot can later be viewed via the devlink-region

 * interface.

 *

 * @returns zero on success, and updates the data pointer. Returns a non-zero

 * error code on failure.

 */

static int ice_devlink_nvm_snapshot(struct devlink *devlink,

				    struct netlink_ext_ack *extack, u8 **data)

{

	struct ice_pf *pf = devlink_priv(devlink);

	struct device *dev = ice_pf_to_dev(pf);

	struct ice_hw *hw = &pf->hw;

	enum ice_status status;

	void *nvm_data;

	u32 nvm_size;



	nvm_size = hw->nvm.flash_size;

	nvm_data = vzalloc(nvm_size);

	if (!nvm_data)

		return -ENOMEM;



	status = ice_acquire_nvm(hw, ICE_RES_READ);

	if (status) {

		dev_dbg(dev, "ice_acquire_nvm failed, err %d aq_err %d\n",

			status, hw->adminq.sq_last_status);

		NL_SET_ERR_MSG_MOD(extack, "Failed to acquire NVM semaphore");

		vfree(nvm_data);

		return -EIO;

	}



	status = ice_read_flat_nvm(hw, 0, &nvm_size, nvm_data, false);

	if (status) {

		dev_dbg(dev, "ice_read_flat_nvm failed after reading %u bytes, err %d aq_err %d\n",

			nvm_size, status, hw->adminq.sq_last_status);

		NL_SET_ERR_MSG_MOD(extack, "Failed to read NVM contents");

		ice_release_nvm(hw);

		vfree(nvm_data);

		return -EIO;

	}



	ice_release_nvm(hw);



	*data = nvm_data;



	return 0;

}



static const struct devlink_region_ops ice_nvm_region_ops = {

	.name = "nvm-flash",

	.destructor = vfree,

	.snapshot = ice_devlink_nvm_snapshot,

};



/**

 * ice_devlink_init_regions - Initialize devlink regions

 * @pf: the PF device structure

 *

 * Create devlink regions used to enable access to dump the contents of the

 * flash memory on the device.

 */

void ice_devlink_init_regions(struct ice_pf *pf)

{

	struct devlink *devlink = priv_to_devlink(pf);

	struct device *dev = ice_pf_to_dev(pf);

	u64 nvm_size;



	nvm_size = pf->hw.nvm.flash_size;

	pf->nvm_region = devlink_region_create(devlink, &ice_nvm_region_ops, 1,

					       nvm_size);

	if (IS_ERR(pf->nvm_region)) {

		dev_err(dev, "failed to create NVM devlink region, err %ld\n",

			PTR_ERR(pf->nvm_region));

		pf->nvm_region = NULL;

	}

}



/**

 * ice_devlink_destroy_regions - Destroy devlink regions

 * @pf: the PF device structure

 *

 * Remove previously created regions for this PF.

 */

void ice_devlink_destroy_regions(struct ice_pf *pf)

{

	if (pf->nvm_region)

		devlink_region_destroy(pf->nvm_region);

}

drivers/net/ethernet/intel/ice/ice_devlink.h

+3 −0
Original line number Diff line number Diff line
@@ -11,4 +11,7 @@ void ice_devlink_unregister(struct ice_pf *pf); 
int ice_devlink_create_port(struct ice_pf *pf);

void ice_devlink_destroy_port(struct ice_pf *pf);



void ice_devlink_init_regions(struct ice_pf *pf);

void ice_devlink_destroy_regions(struct ice_pf *pf);



#endif /* _ICE_DEVLINK_H_ */

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