[PATCH 29/41] staging: lustre: ptlrpc: Move NRS structures out of lustre_net.h

[James Simmons]

From: Chris Horn <hornc@xxxxxxxx>

NRS specific structures are not needed in the rest of the PtlRPC code.
It is more appropriate for these structures to be defined in a
separate header. This commit creates a lustre_nrs.h header for the
generic NRS structures, and policy-specific headers for the various
NRS policies.

Signed-off-by: Chris Horn <hornc@xxxxxxxx>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2667
Reviewed-on: http://review.whamcloud.com/13966
Reviewed-by: Henri Doreau <henri.doreau@xxxxxx>
Reviewed-by: James Simmons <uja.ornl@xxxxxxxxx>
Reviewed-by: Oleg Drokin <oleg.drokin@xxxxxxxxx>
Signed-off-by: James Simmons <jsimmons@xxxxxxxxxxxxx>
---
 drivers/staging/lustre/lustre/include/lustre_net.h |  712 +-------------------
 drivers/staging/lustre/lustre/include/lustre_nrs.h |  717 ++++++++++++++++++++
 .../lustre/lustre/include/lustre_nrs_fifo.h        |   70 ++
 3 files changed, 788 insertions(+), 711 deletions(-)
 create mode 100644 drivers/staging/lustre/lustre/include/lustre_nrs.h
 create mode 100644 drivers/staging/lustre/lustre/include/lustre_nrs_fifo.h

diff --git a/drivers/staging/lustre/lustre/include/lustre_net.h b/drivers/staging/lustre/lustre/include/lustre_net.h
index ab80330..7302238 100644
--- a/drivers/staging/lustre/lustre/include/lustre_net.h
+++ b/drivers/staging/lustre/lustre/include/lustre_net.h
@@ -515,717 +515,7 @@ struct lu_env;
 
 struct ldlm_lock;
 
-/**
- * \defgroup nrs Network Request Scheduler
- * @{
- */
-struct ptlrpc_nrs_policy;
-struct ptlrpc_nrs_resource;
-struct ptlrpc_nrs_request;
-
-/**
- * NRS control operations.
- *
- * These are common for all policies.
- */
-enum ptlrpc_nrs_ctl {
-	/**
-	 * Not a valid opcode.
-	 */
-	PTLRPC_NRS_CTL_INVALID,
-	/**
-	 * Activate the policy.
-	 */
-	PTLRPC_NRS_CTL_START,
-	/**
-	 * Reserved for multiple primary policies, which may be a possibility
-	 * in the future.
-	 */
-	PTLRPC_NRS_CTL_STOP,
-	/**
-	 * Policies can start using opcodes from this value and onwards for
-	 * their own purposes; the assigned value itself is arbitrary.
-	 */
-	PTLRPC_NRS_CTL_1ST_POL_SPEC = 0x20,
-};
-
-/**
- * ORR policy operations
- */
-enum nrs_ctl_orr {
-	NRS_CTL_ORR_RD_QUANTUM = PTLRPC_NRS_CTL_1ST_POL_SPEC,
-	NRS_CTL_ORR_WR_QUANTUM,
-	NRS_CTL_ORR_RD_OFF_TYPE,
-	NRS_CTL_ORR_WR_OFF_TYPE,
-	NRS_CTL_ORR_RD_SUPP_REQ,
-	NRS_CTL_ORR_WR_SUPP_REQ,
-};
-
-/**
- * NRS policy operations.
- *
- * These determine the behaviour of a policy, and are called in response to
- * NRS core events.
- */
-struct ptlrpc_nrs_pol_ops {
-	/**
-	 * Called during policy registration; this operation is optional.
-	 *
-	 * \param[in,out] policy The policy being initialized
-	 */
-	int	(*op_policy_init)(struct ptlrpc_nrs_policy *policy);
-	/**
-	 * Called during policy unregistration; this operation is optional.
-	 *
-	 * \param[in,out] policy The policy being unregistered/finalized
-	 */
-	void	(*op_policy_fini)(struct ptlrpc_nrs_policy *policy);
-	/**
-	 * Called when activating a policy via lprocfs; policies allocate and
-	 * initialize their resources here; this operation is optional.
-	 *
-	 * \param[in,out] policy The policy being started
-	 *
-	 * \see nrs_policy_start_locked()
-	 */
-	int	(*op_policy_start)(struct ptlrpc_nrs_policy *policy);
-	/**
-	 * Called when deactivating a policy via lprocfs; policies deallocate
-	 * their resources here; this operation is optional
-	 *
-	 * \param[in,out] policy The policy being stopped
-	 *
-	 * \see nrs_policy_stop0()
-	 */
-	void	(*op_policy_stop)(struct ptlrpc_nrs_policy *policy);
-	/**
-	 * Used for policy-specific operations; i.e. not generic ones like
-	 * \e PTLRPC_NRS_CTL_START and \e PTLRPC_NRS_CTL_GET_INFO; analogous
-	 * to an ioctl; this operation is optional.
-	 *
-	 * \param[in,out]	 policy The policy carrying out operation \a opc
-	 * \param[in]	  opc	 The command operation being carried out
-	 * \param[in,out] arg	 An generic buffer for communication between the
-	 *			 user and the control operation
-	 *
-	 * \retval -ve error
-	 * \retval   0 success
-	 *
-	 * \see ptlrpc_nrs_policy_control()
-	 */
-	int	(*op_policy_ctl)(struct ptlrpc_nrs_policy *policy,
-				 enum ptlrpc_nrs_ctl opc, void *arg);
-
-	/**
-	 * Called when obtaining references to the resources of the resource
-	 * hierarchy for a request that has arrived for handling at the PTLRPC
-	 * service. Policies should return -ve for requests they do not wish
-	 * to handle. This operation is mandatory.
-	 *
-	 * \param[in,out] policy  The policy we're getting resources for.
-	 * \param[in,out] nrq	  The request we are getting resources for.
-	 * \param[in]	  parent  The parent resource of the resource being
-	 *			  requested; set to NULL if none.
-	 * \param[out]	  resp	  The resource is to be returned here; the
-	 *			  fallback policy in an NRS head should
-	 *			  \e always return a non-NULL pointer value.
-	 * \param[in]  moving_req When set, signifies that this is an attempt
-	 *			  to obtain resources for a request being moved
-	 *			  to the high-priority NRS head by
-	 *			  ldlm_lock_reorder_req().
-	 *			  This implies two things:
-	 *			  1. We are under obd_export::exp_rpc_lock and
-	 *			  so should not sleep.
-	 *			  2. We should not perform non-idempotent or can
-	 *			  skip performing idempotent operations that
-	 *			  were carried out when resources were first
-	 *			  taken for the request when it was initialized
-	 *			  in ptlrpc_nrs_req_initialize().
-	 *
-	 * \retval 0, +ve The level of the returned resource in the resource
-	 *		  hierarchy; currently only 0 (for a non-leaf resource)
-	 *		  and 1 (for a leaf resource) are supported by the
-	 *		  framework.
-	 * \retval -ve	  error
-	 *
-	 * \see ptlrpc_nrs_req_initialize()
-	 * \see ptlrpc_nrs_hpreq_add_nolock()
-	 */
-	int	(*op_res_get)(struct ptlrpc_nrs_policy *policy,
-			      struct ptlrpc_nrs_request *nrq,
-			      const struct ptlrpc_nrs_resource *parent,
-			      struct ptlrpc_nrs_resource **resp,
-			      bool moving_req);
-	/**
-	 * Called when releasing references taken for resources in the resource
-	 * hierarchy for the request; this operation is optional.
-	 *
-	 * \param[in,out] policy The policy the resource belongs to
-	 * \param[in] res	 The resource to be freed
-	 *
-	 * \see ptlrpc_nrs_req_finalize()
-	 * \see ptlrpc_nrs_hpreq_add_nolock()
-	 */
-	void	(*op_res_put)(struct ptlrpc_nrs_policy *policy,
-			      const struct ptlrpc_nrs_resource *res);
-
-	/**
-	 * Obtains a request for handling from the policy, and optionally
-	 * removes the request from the policy; this operation is mandatory.
-	 *
-	 * \param[in,out] policy The policy to poll
-	 * \param[in]	  peek	 When set, signifies that we just want to
-	 *			 examine the request, and not handle it, so the
-	 *			 request is not removed from the policy.
-	 * \param[in]	  force	 When set, it will force a policy to return a
-	 *			 request if it has one queued.
-	 *
-	 * \retval NULL No request available for handling
-	 * \retval valid-pointer The request polled for handling
-	 *
-	 * \see ptlrpc_nrs_req_get_nolock()
-	 */
-	struct ptlrpc_nrs_request *
-		(*op_req_get)(struct ptlrpc_nrs_policy *policy, bool peek,
-			      bool force);
-	/**
-	 * Called when attempting to add a request to a policy for later
-	 * handling; this operation is mandatory.
-	 *
-	 * \param[in,out] policy  The policy on which to enqueue \a nrq
-	 * \param[in,out] nrq The request to enqueue
-	 *
-	 * \retval 0	success
-	 * \retval != 0	error
-	 *
-	 * \see ptlrpc_nrs_req_add_nolock()
-	 */
-	int	(*op_req_enqueue)(struct ptlrpc_nrs_policy *policy,
-				  struct ptlrpc_nrs_request *nrq);
-	/**
-	 * Removes a request from the policy's set of pending requests. Normally
-	 * called after a request has been polled successfully from the policy
-	 * for handling; this operation is mandatory.
-	 *
-	 * \param[in,out] policy The policy the request \a nrq belongs to
-	 * \param[in,out] nrq    The request to dequeue
-	 */
-	void	(*op_req_dequeue)(struct ptlrpc_nrs_policy *policy,
-				  struct ptlrpc_nrs_request *nrq);
-	/**
-	 * Called after the request being carried out. Could be used for
-	 * job/resource control; this operation is optional.
-	 *
-	 * \param[in,out] policy The policy which is stopping to handle request
-	 *			 \a nrq
-	 * \param[in,out] nrq	 The request
-	 *
-	 * \pre assert_spin_locked(&svcpt->scp_req_lock)
-	 *
-	 * \see ptlrpc_nrs_req_stop_nolock()
-	 */
-	void	(*op_req_stop)(struct ptlrpc_nrs_policy *policy,
-			       struct ptlrpc_nrs_request *nrq);
-	/**
-	 * Registers the policy's lprocfs interface with a PTLRPC service.
-	 *
-	 * \param[in] svc The service
-	 *
-	 * \retval 0	success
-	 * \retval != 0	error
-	 */
-	int	(*op_lprocfs_init)(struct ptlrpc_service *svc);
-	/**
-	 * Unegisters the policy's lprocfs interface with a PTLRPC service.
-	 *
-	 * In cases of failed policy registration in
-	 * \e ptlrpc_nrs_policy_register(), this function may be called for a
-	 * service which has not registered the policy successfully, so
-	 * implementations of this method should make sure their operations are
-	 * safe in such cases.
-	 *
-	 * \param[in] svc The service
-	 */
-	void	(*op_lprocfs_fini)(struct ptlrpc_service *svc);
-};
-
-/**
- * Policy flags
- */
-enum nrs_policy_flags {
-	/**
-	 * Fallback policy, use this flag only on a single supported policy per
-	 * service. The flag cannot be used on policies that use
-	 * \e PTLRPC_NRS_FL_REG_EXTERN
-	 */
-	PTLRPC_NRS_FL_FALLBACK		= (1 << 0),
-	/**
-	 * Start policy immediately after registering.
-	 */
-	PTLRPC_NRS_FL_REG_START		= (1 << 1),
-	/**
-	 * This is a policy registering from a module different to the one NRS
-	 * core ships in (currently ptlrpc).
-	 */
-	PTLRPC_NRS_FL_REG_EXTERN	= (1 << 2),
-};
-
-/**
- * NRS queue type.
- *
- * Denotes whether an NRS instance is for handling normal or high-priority
- * RPCs, or whether an operation pertains to one or both of the NRS instances
- * in a service.
- */
-enum ptlrpc_nrs_queue_type {
-	PTLRPC_NRS_QUEUE_REG	= (1 << 0),
-	PTLRPC_NRS_QUEUE_HP	= (1 << 1),
-	PTLRPC_NRS_QUEUE_BOTH	= (PTLRPC_NRS_QUEUE_REG | PTLRPC_NRS_QUEUE_HP)
-};
-
-/**
- * NRS head
- *
- * A PTLRPC service has at least one NRS head instance for handling normal
- * priority RPCs, and may optionally have a second NRS head instance for
- * handling high-priority RPCs. Each NRS head maintains a list of available
- * policies, of which one and only one policy is acting as the fallback policy,
- * and optionally a different policy may be acting as the primary policy. For
- * all RPCs handled by this NRS head instance, NRS core will first attempt to
- * enqueue the RPC using the primary policy (if any). The fallback policy is
- * used in the following cases:
- * - when there was no primary policy in the
- *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state at the time the request
- *   was initialized.
- * - when the primary policy that was at the
- *   ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
- *   RPC was initialized, denoted it did not wish, or for some other reason was
- *   not able to handle the request, by returning a non-valid NRS resource
- *   reference.
- * - when the primary policy that was at the
- *   ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
- *   RPC was initialized, fails later during the request enqueueing stage.
- *
- * \see nrs_resource_get_safe()
- * \see nrs_request_enqueue()
- */
-struct ptlrpc_nrs {
-	spinlock_t			nrs_lock;
-	/** XXX Possibly replace svcpt->scp_req_lock with another lock here. */
-	/**
-	 * List of registered policies
-	 */
-	struct list_head			nrs_policy_list;
-	/**
-	 * List of policies with queued requests. Policies that have any
-	 * outstanding requests are queued here, and this list is queried
-	 * in a round-robin manner from NRS core when obtaining a request
-	 * for handling. This ensures that requests from policies that at some
-	 * point transition away from the
-	 * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state are drained.
-	 */
-	struct list_head			nrs_policy_queued;
-	/**
-	 * Service partition for this NRS head
-	 */
-	struct ptlrpc_service_part     *nrs_svcpt;
-	/**
-	 * Primary policy, which is the preferred policy for handling RPCs
-	 */
-	struct ptlrpc_nrs_policy       *nrs_policy_primary;
-	/**
-	 * Fallback policy, which is the backup policy for handling RPCs
-	 */
-	struct ptlrpc_nrs_policy       *nrs_policy_fallback;
-	/**
-	 * This NRS head handles either HP or regular requests
-	 */
-	enum ptlrpc_nrs_queue_type	nrs_queue_type;
-	/**
-	 * # queued requests from all policies in this NRS head
-	 */
-	unsigned long			nrs_req_queued;
-	/**
-	 * # scheduled requests from all policies in this NRS head
-	 */
-	unsigned long			nrs_req_started;
-	/**
-	 * # policies on this NRS
-	 */
-	unsigned			nrs_num_pols;
-	/**
-	 * This NRS head is in progress of starting a policy
-	 */
-	unsigned			nrs_policy_starting:1;
-	/**
-	 * In progress of shutting down the whole NRS head; used during
-	 * unregistration
-	 */
-	unsigned			nrs_stopping:1;
-};
-
-#define NRS_POL_NAME_MAX		16
-
-struct ptlrpc_nrs_pol_desc;
-
-/**
- * Service compatibility predicate; this determines whether a policy is adequate
- * for handling RPCs of a particular PTLRPC service.
- *
- * XXX:This should give the same result during policy registration and
- * unregistration, and for all partitions of a service; so the result should not
- * depend on temporal service or other properties, that may influence the
- * result.
- */
-typedef bool (*nrs_pol_desc_compat_t) (const struct ptlrpc_service *svc,
-				       const struct ptlrpc_nrs_pol_desc *desc);
-
-struct ptlrpc_nrs_pol_conf {
-	/**
-	 * Human-readable policy name
-	 */
-	char				   nc_name[NRS_POL_NAME_MAX];
-	/**
-	 * NRS operations for this policy
-	 */
-	const struct ptlrpc_nrs_pol_ops	  *nc_ops;
-	/**
-	 * Service compatibility predicate
-	 */
-	nrs_pol_desc_compat_t		   nc_compat;
-	/**
-	 * Set for policies that support a single ptlrpc service, i.e. ones that
-	 * have \a pd_compat set to nrs_policy_compat_one(). The variable value
-	 * depicts the name of the single service that such policies are
-	 * compatible with.
-	 */
-	const char			  *nc_compat_svc_name;
-	/**
-	 * Owner module for this policy descriptor; policies registering from a
-	 * different module to the one the NRS framework is held within
-	 * (currently ptlrpc), should set this field to THIS_MODULE.
-	 */
-	struct module			  *nc_owner;
-	/**
-	 * Policy registration flags; a bitmask of \e nrs_policy_flags
-	 */
-	unsigned			   nc_flags;
-};
-
-/**
- * NRS policy registering descriptor
- *
- * Is used to hold a description of a policy that can be passed to NRS core in
- * order to register the policy with NRS heads in different PTLRPC services.
- */
-struct ptlrpc_nrs_pol_desc {
-	/**
-	 * Human-readable policy name
-	 */
-	char					pd_name[NRS_POL_NAME_MAX];
-	/**
-	 * Link into nrs_core::nrs_policies
-	 */
-	struct list_head				pd_list;
-	/**
-	 * NRS operations for this policy
-	 */
-	const struct ptlrpc_nrs_pol_ops	       *pd_ops;
-	/**
-	 * Service compatibility predicate
-	 */
-	nrs_pol_desc_compat_t			pd_compat;
-	/**
-	 * Set for policies that are compatible with only one PTLRPC service.
-	 *
-	 * \see ptlrpc_nrs_pol_conf::nc_compat_svc_name
-	 */
-	const char			       *pd_compat_svc_name;
-	/**
-	 * Owner module for this policy descriptor.
-	 *
-	 * We need to hold a reference to the module whenever we might make use
-	 * of any of the module's contents, i.e.
-	 * - If one or more instances of the policy are at a state where they
-	 *   might be handling a request, i.e.
-	 *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED or
-	 *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPING as we will have to
-	 *   call into the policy's ptlrpc_nrs_pol_ops() handlers. A reference
-	 *   is taken on the module when
-	 *   \e ptlrpc_nrs_pol_desc::pd_refs becomes 1, and released when it
-	 *   becomes 0, so that we hold only one reference to the module maximum
-	 *   at any time.
-	 *
-	 *   We do not need to hold a reference to the module, even though we
-	 *   might use code and data from the module, in the following cases:
-	 * - During external policy registration, because this should happen in
-	 *   the module's init() function, in which case the module is safe from
-	 *   removal because a reference is being held on the module by the
-	 *   kernel, and iirc kmod (and I guess module-init-tools also) will
-	 *   serialize any racing processes properly anyway.
-	 * - During external policy unregistration, because this should happen
-	 *   in a module's exit() function, and any attempts to start a policy
-	 *   instance would need to take a reference on the module, and this is
-	 *   not possible once we have reached the point where the exit()
-	 *   handler is called.
-	 * - During service registration and unregistration, as service setup
-	 *   and cleanup, and policy registration, unregistration and policy
-	 *   instance starting, are serialized by \e nrs_core::nrs_mutex, so
-	 *   as long as users adhere to the convention of registering policies
-	 *   in init() and unregistering them in module exit() functions, there
-	 *   should not be a race between these operations.
-	 * - During any policy-specific lprocfs operations, because a reference
-	 *   is held by the kernel on a proc entry that has been entered by a
-	 *   syscall, so as long as proc entries are removed during unregistration time,
-	 *   then unregistration and lprocfs operations will be properly
-	 *   serialized.
-	 */
-	struct module			       *pd_owner;
-	/**
-	 * Bitmask of \e nrs_policy_flags
-	 */
-	unsigned				pd_flags;
-	/**
-	 * # of references on this descriptor
-	 */
-	atomic_t				pd_refs;
-};
-
-/**
- * NRS policy state
- *
- * Policies transition from one state to the other during their lifetime
- */
-enum ptlrpc_nrs_pol_state {
-	/**
-	 * Not a valid policy state.
-	 */
-	NRS_POL_STATE_INVALID,
-	/**
-	 * Policies are at this state either at the start of their life, or
-	 * transition here when the user selects a different policy to act
-	 * as the primary one.
-	 */
-	NRS_POL_STATE_STOPPED,
-	/**
-	 * Policy is progress of stopping
-	 */
-	NRS_POL_STATE_STOPPING,
-	/**
-	 * Policy is in progress of starting
-	 */
-	NRS_POL_STATE_STARTING,
-	/**
-	 * A policy is in this state in two cases:
-	 * - it is the fallback policy, which is always in this state.
-	 * - it has been activated by the user; i.e. it is the primary policy,
-	 */
-	NRS_POL_STATE_STARTED,
-};
-
-/**
- * NRS policy information
- *
- * Used for obtaining information for the status of a policy via lprocfs
- */
-struct ptlrpc_nrs_pol_info {
-	/**
-	 * Policy name
-	 */
-	char				pi_name[NRS_POL_NAME_MAX];
-	/**
-	 * Current policy state
-	 */
-	enum ptlrpc_nrs_pol_state	pi_state;
-	/**
-	 * # RPCs enqueued for later dispatching by the policy
-	 */
-	long				pi_req_queued;
-	/**
-	 * # RPCs started for dispatch by the policy
-	 */
-	long				pi_req_started;
-	/**
-	 * Is this a fallback policy?
-	 */
-	unsigned			pi_fallback:1;
-};
-
-/**
- * NRS policy
- *
- * There is one instance of this for each policy in each NRS head of each
- * PTLRPC service partition.
- */
-struct ptlrpc_nrs_policy {
-	/**
-	 * Linkage into the NRS head's list of policies,
-	 * ptlrpc_nrs:nrs_policy_list
-	 */
-	struct list_head			pol_list;
-	/**
-	 * Linkage into the NRS head's list of policies with enqueued
-	 * requests ptlrpc_nrs:nrs_policy_queued
-	 */
-	struct list_head			pol_list_queued;
-	/**
-	 * Current state of this policy
-	 */
-	enum ptlrpc_nrs_pol_state	pol_state;
-	/**
-	 * Bitmask of nrs_policy_flags
-	 */
-	unsigned			pol_flags;
-	/**
-	 * # RPCs enqueued for later dispatching by the policy
-	 */
-	long				pol_req_queued;
-	/**
-	 * # RPCs started for dispatch by the policy
-	 */
-	long				pol_req_started;
-	/**
-	 * Usage Reference count taken on the policy instance
-	 */
-	long				pol_ref;
-	/**
-	 * The NRS head this policy has been created at
-	 */
-	struct ptlrpc_nrs	       *pol_nrs;
-	/**
-	 * Private policy data; varies by policy type
-	 */
-	void			       *pol_private;
-	/**
-	 * Policy descriptor for this policy instance.
-	 */
-	struct ptlrpc_nrs_pol_desc     *pol_desc;
-};
-
-/**
- * NRS resource
- *
- * Resources are embedded into two types of NRS entities:
- * - Inside NRS policies, in the policy's private data in
- *   ptlrpc_nrs_policy::pol_private
- * - In objects that act as prime-level scheduling entities in different NRS
- *   policies; e.g. on a policy that performs round robin or similar order
- *   scheduling across client NIDs, there would be one NRS resource per unique
- *   client NID. On a policy which performs round robin scheduling across
- *   backend filesystem objects, there would be one resource associated with
- *   each of the backend filesystem objects partaking in the scheduling
- *   performed by the policy.
- *
- * NRS resources share a parent-child relationship, in which resources embedded
- * in policy instances are the parent entities, with all scheduling entities
- * a policy schedules across being the children, thus forming a simple resource
- * hierarchy. This hierarchy may be extended with one or more levels in the
- * future if the ability to have more than one primary policy is added.
- *
- * Upon request initialization, references to the then active NRS policies are
- * taken and used to later handle the dispatching of the request with one of
- * these policies.
- *
- * \see nrs_resource_get_safe()
- * \see ptlrpc_nrs_req_add()
- */
-struct ptlrpc_nrs_resource {
-	/**
-	 * This NRS resource's parent; is NULL for resources embedded in NRS
-	 * policy instances; i.e. those are top-level ones.
-	 */
-	struct ptlrpc_nrs_resource     *res_parent;
-	/**
-	 * The policy associated with this resource.
-	 */
-	struct ptlrpc_nrs_policy       *res_policy;
-};
-
-enum {
-	NRS_RES_FALLBACK,
-	NRS_RES_PRIMARY,
-	NRS_RES_MAX
-};
-
-/* \name fifo
- *
- * FIFO policy
- *
- * This policy is a logical wrapper around previous, non-NRS functionality.
- * It dispatches RPCs in the same order as they arrive from the network. This
- * policy is currently used as the fallback policy, and the only enabled policy
- * on all NRS heads of all PTLRPC service partitions.
- * @{
- */
-
-/**
- * Private data structure for the FIFO policy
- */
-struct nrs_fifo_head {
-	/**
-	 * Resource object for policy instance.
-	 */
-	struct ptlrpc_nrs_resource	fh_res;
-	/**
-	 * List of queued requests.
-	 */
-	struct list_head			fh_list;
-	/**
-	 * For debugging purposes.
-	 */
-	__u64				fh_sequence;
-};
-
-struct nrs_fifo_req {
-	struct list_head		fr_list;
-	__u64			fr_sequence;
-};
-
-/** @} fifo */
-
-/**
- * NRS request
- *
- * Instances of this object exist embedded within ptlrpc_request; the main
- * purpose of this object is to hold references to the request's resources
- * for the lifetime of the request, and to hold properties that policies use
- * use for determining the request's scheduling priority.
- */
-struct ptlrpc_nrs_request {
-	/**
-	 * The request's resource hierarchy.
-	 */
-	struct ptlrpc_nrs_resource     *nr_res_ptrs[NRS_RES_MAX];
-	/**
-	 * Index into ptlrpc_nrs_request::nr_res_ptrs of the resource of the
-	 * policy that was used to enqueue the request.
-	 *
-	 * \see nrs_request_enqueue()
-	 */
-	unsigned			nr_res_idx;
-	unsigned			nr_initialized:1;
-	unsigned			nr_enqueued:1;
-	unsigned			nr_started:1;
-	unsigned			nr_finalized:1;
-
-	/**
-	 * Policy-specific fields, used for determining a request's scheduling
-	 * priority, and other supporting functionality.
-	 */
-	union {
-		/**
-		 * Fields for the FIFO policy
-		 */
-		struct nrs_fifo_req	fifo;
-	} nr_u;
-	/**
-	 * Externally-registering policies may want to use this to allocate
-	 * their own request properties.
-	 */
-	void			       *ext;
-};
-
-/** @} nrs */
+#include "lustre_nrs.h"
 
 /**
  * Basic request prioritization operations structure.
diff --git a/drivers/staging/lustre/lustre/include/lustre_nrs.h b/drivers/staging/lustre/lustre/include/lustre_nrs.h
new file mode 100644
index 0000000..a5028aa
--- /dev/null
+++ b/drivers/staging/lustre/lustre/include/lustre_nrs.h
@@ -0,0 +1,717 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * Copyright 2012 Xyratex Technology Limited
+ */
+/*
+ *
+ * Network Request Scheduler (NRS)
+ *
+ */
+
+#ifndef _LUSTRE_NRS_H
+#define _LUSTRE_NRS_H
+
+/**
+ * \defgroup nrs Network Request Scheduler
+ * @{
+ */
+struct ptlrpc_nrs_policy;
+struct ptlrpc_nrs_resource;
+struct ptlrpc_nrs_request;
+
+/**
+ * NRS control operations.
+ *
+ * These are common for all policies.
+ */
+enum ptlrpc_nrs_ctl {
+	/**
+	 * Not a valid opcode.
+	 */
+	PTLRPC_NRS_CTL_INVALID,
+	/**
+	 * Activate the policy.
+	 */
+	PTLRPC_NRS_CTL_START,
+	/**
+	 * Reserved for multiple primary policies, which may be a possibility
+	 * in the future.
+	 */
+	PTLRPC_NRS_CTL_STOP,
+	/**
+	 * Policies can start using opcodes from this value and onwards for
+	 * their own purposes; the assigned value itself is arbitrary.
+	 */
+	PTLRPC_NRS_CTL_1ST_POL_SPEC = 0x20,
+};
+
+/**
+ * NRS policy operations.
+ *
+ * These determine the behaviour of a policy, and are called in response to
+ * NRS core events.
+ */
+struct ptlrpc_nrs_pol_ops {
+	/**
+	 * Called during policy registration; this operation is optional.
+	 *
+	 * \param[in,out] policy The policy being initialized
+	 */
+	int	(*op_policy_init)(struct ptlrpc_nrs_policy *policy);
+	/**
+	 * Called during policy unregistration; this operation is optional.
+	 *
+	 * \param[in,out] policy The policy being unregistered/finalized
+	 */
+	void	(*op_policy_fini)(struct ptlrpc_nrs_policy *policy);
+	/**
+	 * Called when activating a policy via lprocfs; policies allocate and
+	 * initialize their resources here; this operation is optional.
+	 *
+	 * \param[in,out] policy The policy being started
+	 *
+	 * \see nrs_policy_start_locked()
+	 */
+	int	(*op_policy_start)(struct ptlrpc_nrs_policy *policy);
+	/**
+	 * Called when deactivating a policy via lprocfs; policies deallocate
+	 * their resources here; this operation is optional
+	 *
+	 * \param[in,out] policy The policy being stopped
+	 *
+	 * \see nrs_policy_stop0()
+	 */
+	void	(*op_policy_stop)(struct ptlrpc_nrs_policy *policy);
+	/**
+	 * Used for policy-specific operations; i.e. not generic ones like
+	 * \e PTLRPC_NRS_CTL_START and \e PTLRPC_NRS_CTL_GET_INFO; analogous
+	 * to an ioctl; this operation is optional.
+	 *
+	 * \param[in,out]	 policy The policy carrying out operation \a opc
+	 * \param[in]	  opc	 The command operation being carried out
+	 * \param[in,out] arg	 An generic buffer for communication between the
+	 *			 user and the control operation
+	 *
+	 * \retval -ve error
+	 * \retval   0 success
+	 *
+	 * \see ptlrpc_nrs_policy_control()
+	 */
+	int	(*op_policy_ctl)(struct ptlrpc_nrs_policy *policy,
+				 enum ptlrpc_nrs_ctl opc, void *arg);
+
+	/**
+	 * Called when obtaining references to the resources of the resource
+	 * hierarchy for a request that has arrived for handling at the PTLRPC
+	 * service. Policies should return -ve for requests they do not wish
+	 * to handle. This operation is mandatory.
+	 *
+	 * \param[in,out] policy  The policy we're getting resources for.
+	 * \param[in,out] nrq	  The request we are getting resources for.
+	 * \param[in]	  parent  The parent resource of the resource being
+	 *			  requested; set to NULL if none.
+	 * \param[out]	  resp	  The resource is to be returned here; the
+	 *			  fallback policy in an NRS head should
+	 *			  \e always return a non-NULL pointer value.
+	 * \param[in]  moving_req When set, signifies that this is an attempt
+	 *			  to obtain resources for a request being moved
+	 *			  to the high-priority NRS head by
+	 *			  ldlm_lock_reorder_req().
+	 *			  This implies two things:
+	 *			  1. We are under obd_export::exp_rpc_lock and
+	 *			  so should not sleep.
+	 *			  2. We should not perform non-idempotent or can
+	 *			  skip performing idempotent operations that
+	 *			  were carried out when resources were first
+	 *			  taken for the request when it was initialized
+	 *			  in ptlrpc_nrs_req_initialize().
+	 *
+	 * \retval 0, +ve The level of the returned resource in the resource
+	 *		  hierarchy; currently only 0 (for a non-leaf resource)
+	 *		  and 1 (for a leaf resource) are supported by the
+	 *		  framework.
+	 * \retval -ve	  error
+	 *
+	 * \see ptlrpc_nrs_req_initialize()
+	 * \see ptlrpc_nrs_hpreq_add_nolock()
+	 * \see ptlrpc_nrs_req_hp_move()
+	 */
+	int	(*op_res_get)(struct ptlrpc_nrs_policy *policy,
+			      struct ptlrpc_nrs_request *nrq,
+			      const struct ptlrpc_nrs_resource *parent,
+			      struct ptlrpc_nrs_resource **resp,
+			      bool moving_req);
+	/**
+	 * Called when releasing references taken for resources in the resource
+	 * hierarchy for the request; this operation is optional.
+	 *
+	 * \param[in,out] policy The policy the resource belongs to
+	 * \param[in] res	 The resource to be freed
+	 *
+	 * \see ptlrpc_nrs_req_finalize()
+	 * \see ptlrpc_nrs_hpreq_add_nolock()
+	 * \see ptlrpc_nrs_req_hp_move()
+	 */
+	void	(*op_res_put)(struct ptlrpc_nrs_policy *policy,
+			      const struct ptlrpc_nrs_resource *res);
+
+	/**
+	 * Obtains a request for handling from the policy, and optionally
+	 * removes the request from the policy; this operation is mandatory.
+	 *
+	 * \param[in,out] policy The policy to poll
+	 * \param[in]	  peek	 When set, signifies that we just want to
+	 *			 examine the request, and not handle it, so the
+	 *			 request is not removed from the policy.
+	 * \param[in]	  force  When set, it will force a policy to return a
+	 *			 request if it has one queued.
+	 *
+	 * \retval NULL No request available for handling
+	 * \retval valid-pointer The request polled for handling
+	 *
+	 * \see ptlrpc_nrs_req_get_nolock()
+	 */
+	struct ptlrpc_nrs_request *
+		(*op_req_get)(struct ptlrpc_nrs_policy *policy, bool peek,
+			      bool force);
+	/**
+	 * Called when attempting to add a request to a policy for later
+	 * handling; this operation is mandatory.
+	 *
+	 * \param[in,out] policy  The policy on which to enqueue \a nrq
+	 * \param[in,out] nrq The request to enqueue
+	 *
+	 * \retval 0	success
+	 * \retval != 0 error
+	 *
+	 * \see ptlrpc_nrs_req_add_nolock()
+	 */
+	int	(*op_req_enqueue)(struct ptlrpc_nrs_policy *policy,
+				  struct ptlrpc_nrs_request *nrq);
+	/**
+	 * Removes a request from the policy's set of pending requests. Normally
+	 * called after a request has been polled successfully from the policy
+	 * for handling; this operation is mandatory.
+	 *
+	 * \param[in,out] policy The policy the request \a nrq belongs to
+	 * \param[in,out] nrq	 The request to dequeue
+	 *
+	 * \see ptlrpc_nrs_req_del_nolock()
+	 */
+	void	(*op_req_dequeue)(struct ptlrpc_nrs_policy *policy,
+				  struct ptlrpc_nrs_request *nrq);
+	/**
+	 * Called after the request being carried out. Could be used for
+	 * job/resource control; this operation is optional.
+	 *
+	 * \param[in,out] policy The policy which is stopping to handle request
+	 *			 \a nrq
+	 * \param[in,out] nrq	 The request
+	 *
+	 * \pre assert_spin_locked(&svcpt->scp_req_lock)
+	 *
+	 * \see ptlrpc_nrs_req_stop_nolock()
+	 */
+	void	(*op_req_stop)(struct ptlrpc_nrs_policy *policy,
+			       struct ptlrpc_nrs_request *nrq);
+	/**
+	 * Registers the policy's lprocfs interface with a PTLRPC service.
+	 *
+	 * \param[in] svc The service
+	 *
+	 * \retval 0	success
+	 * \retval != 0 error
+	 */
+	int	(*op_lprocfs_init)(struct ptlrpc_service *svc);
+	/**
+	 * Unegisters the policy's lprocfs interface with a PTLRPC service.
+	 *
+	 * In cases of failed policy registration in
+	 * \e ptlrpc_nrs_policy_register(), this function may be called for a
+	 * service which has not registered the policy successfully, so
+	 * implementations of this method should make sure their operations are
+	 * safe in such cases.
+	 *
+	 * \param[in] svc The service
+	 */
+	void	(*op_lprocfs_fini)(struct ptlrpc_service *svc);
+};
+
+/**
+ * Policy flags
+ */
+enum nrs_policy_flags {
+	/**
+	 * Fallback policy, use this flag only on a single supported policy per
+	 * service. The flag cannot be used on policies that use
+	 * \e PTLRPC_NRS_FL_REG_EXTERN
+	 */
+	PTLRPC_NRS_FL_FALLBACK		= BIT(0),
+	/**
+	 * Start policy immediately after registering.
+	 */
+	PTLRPC_NRS_FL_REG_START		= BIT(1),
+	/**
+	 * This is a policy registering from a module different to the one NRS
+	 * core ships in (currently ptlrpc).
+	 */
+	PTLRPC_NRS_FL_REG_EXTERN	= BIT(2),
+};
+
+/**
+ * NRS queue type.
+ *
+ * Denotes whether an NRS instance is for handling normal or high-priority
+ * RPCs, or whether an operation pertains to one or both of the NRS instances
+ * in a service.
+ */
+enum ptlrpc_nrs_queue_type {
+	PTLRPC_NRS_QUEUE_REG	= BIT(0),
+	PTLRPC_NRS_QUEUE_HP	= BIT(1),
+	PTLRPC_NRS_QUEUE_BOTH	= (PTLRPC_NRS_QUEUE_REG | PTLRPC_NRS_QUEUE_HP)
+};
+
+/**
+ * NRS head
+ *
+ * A PTLRPC service has at least one NRS head instance for handling normal
+ * priority RPCs, and may optionally have a second NRS head instance for
+ * handling high-priority RPCs. Each NRS head maintains a list of available
+ * policies, of which one and only one policy is acting as the fallback policy,
+ * and optionally a different policy may be acting as the primary policy. For
+ * all RPCs handled by this NRS head instance, NRS core will first attempt to
+ * enqueue the RPC using the primary policy (if any). The fallback policy is
+ * used in the following cases:
+ * - when there was no primary policy in the
+ *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state at the time the request
+ *   was initialized.
+ * - when the primary policy that was at the
+ *   ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
+ *   RPC was initialized, denoted it did not wish, or for some other reason was
+ *   not able to handle the request, by returning a non-valid NRS resource
+ *   reference.
+ * - when the primary policy that was at the
+ *   ptlrpc_nrs_pol_state::PTLRPC_NRS_POL_STATE_STARTED state at the time the
+ *   RPC was initialized, fails later during the request enqueueing stage.
+ *
+ * \see nrs_resource_get_safe()
+ * \see nrs_request_enqueue()
+ */
+struct ptlrpc_nrs {
+	spinlock_t			nrs_lock;
+	/** XXX Possibly replace svcpt->scp_req_lock with another lock here. */
+	/**
+	 * List of registered policies
+	 */
+	struct list_head		nrs_policy_list;
+	/**
+	 * List of policies with queued requests. Policies that have any
+	 * outstanding requests are queued here, and this list is queried
+	 * in a round-robin manner from NRS core when obtaining a request
+	 * for handling. This ensures that requests from policies that at some
+	 * point transition away from the
+	 * ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED state are drained.
+	 */
+	struct list_head		nrs_policy_queued;
+	/**
+	 * Service partition for this NRS head
+	 */
+	struct ptlrpc_service_part     *nrs_svcpt;
+	/**
+	 * Primary policy, which is the preferred policy for handling RPCs
+	 */
+	struct ptlrpc_nrs_policy       *nrs_policy_primary;
+	/**
+	 * Fallback policy, which is the backup policy for handling RPCs
+	 */
+	struct ptlrpc_nrs_policy       *nrs_policy_fallback;
+	/**
+	 * This NRS head handles either HP or regular requests
+	 */
+	enum ptlrpc_nrs_queue_type	nrs_queue_type;
+	/**
+	 * # queued requests from all policies in this NRS head
+	 */
+	unsigned long			nrs_req_queued;
+	/**
+	 * # scheduled requests from all policies in this NRS head
+	 */
+	unsigned long			nrs_req_started;
+	/**
+	 * # policies on this NRS
+	 */
+	unsigned int			nrs_num_pols;
+	/**
+	 * This NRS head is in progress of starting a policy
+	 */
+	unsigned int			nrs_policy_starting:1;
+	/**
+	 * In progress of shutting down the whole NRS head; used during
+	 * unregistration
+	 */
+	unsigned int			nrs_stopping:1;
+	/**
+	 * NRS policy is throttling request
+	 */
+	unsigned int			nrs_throttling:1;
+};
+
+#define NRS_POL_NAME_MAX		16
+#define NRS_POL_ARG_MAX			16
+
+struct ptlrpc_nrs_pol_desc;
+
+/**
+ * Service compatibility predicate; this determines whether a policy is adequate
+ * for handling RPCs of a particular PTLRPC service.
+ *
+ * XXX:This should give the same result during policy registration and
+ * unregistration, and for all partitions of a service; so the result should not
+ * depend on temporal service or other properties, that may influence the
+ * result.
+ */
+typedef bool (*nrs_pol_desc_compat_t)(const struct ptlrpc_service *svc,
+				      const struct ptlrpc_nrs_pol_desc *desc);
+
+struct ptlrpc_nrs_pol_conf {
+	/**
+	 * Human-readable policy name
+	 */
+	char				   nc_name[NRS_POL_NAME_MAX];
+	/**
+	 * NRS operations for this policy
+	 */
+	const struct ptlrpc_nrs_pol_ops   *nc_ops;
+	/**
+	 * Service compatibility predicate
+	 */
+	nrs_pol_desc_compat_t		   nc_compat;
+	/**
+	 * Set for policies that support a single ptlrpc service, i.e. ones that
+	 * have \a pd_compat set to nrs_policy_compat_one(). The variable value
+	 * depicts the name of the single service that such policies are
+	 * compatible with.
+	 */
+	const char			  *nc_compat_svc_name;
+	/**
+	 * Owner module for this policy descriptor; policies registering from a
+	 * different module to the one the NRS framework is held within
+	 * (currently ptlrpc), should set this field to THIS_MODULE.
+	 */
+	struct module			  *nc_owner;
+	/**
+	 * Policy registration flags; a bitmask of \e nrs_policy_flags
+	 */
+	unsigned int			   nc_flags;
+};
+
+/**
+ * NRS policy registering descriptor
+ *
+ * Is used to hold a description of a policy that can be passed to NRS core in
+ * order to register the policy with NRS heads in different PTLRPC services.
+ */
+struct ptlrpc_nrs_pol_desc {
+	/**
+	 * Human-readable policy name
+	 */
+	char					pd_name[NRS_POL_NAME_MAX];
+	/**
+	 * Link into nrs_core::nrs_policies
+	 */
+	struct list_head			pd_list;
+	/**
+	 * NRS operations for this policy
+	 */
+	const struct ptlrpc_nrs_pol_ops        *pd_ops;
+	/**
+	 * Service compatibility predicate
+	 */
+	nrs_pol_desc_compat_t			pd_compat;
+	/**
+	 * Set for policies that are compatible with only one PTLRPC service.
+	 *
+	 * \see ptlrpc_nrs_pol_conf::nc_compat_svc_name
+	 */
+	const char			       *pd_compat_svc_name;
+	/**
+	 * Owner module for this policy descriptor.
+	 *
+	 * We need to hold a reference to the module whenever we might make use
+	 * of any of the module's contents, i.e.
+	 * - If one or more instances of the policy are at a state where they
+	 *   might be handling a request, i.e.
+	 *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STARTED or
+	 *   ptlrpc_nrs_pol_state::NRS_POL_STATE_STOPPING as we will have to
+	 *   call into the policy's ptlrpc_nrs_pol_ops() handlers. A reference
+	 *   is taken on the module when
+	 *   \e ptlrpc_nrs_pol_desc::pd_refs becomes 1, and released when it
+	 *   becomes 0, so that we hold only one reference to the module maximum
+	 *   at any time.
+	 *
+	 *   We do not need to hold a reference to the module, even though we
+	 *   might use code and data from the module, in the following cases:
+	 * - During external policy registration, because this should happen in
+	 *   the module's init() function, in which case the module is safe from
+	 *   removal because a reference is being held on the module by the
+	 *   kernel, and iirc kmod (and I guess module-init-tools also) will
+	 *   serialize any racing processes properly anyway.
+	 * - During external policy unregistration, because this should happen
+	 *   in a module's exit() function, and any attempts to start a policy
+	 *   instance would need to take a reference on the module, and this is
+	 *   not possible once we have reached the point where the exit()
+	 *   handler is called.
+	 * - During service registration and unregistration, as service setup
+	 *   and cleanup, and policy registration, unregistration and policy
+	 *   instance starting, are serialized by \e nrs_core::nrs_mutex, so
+	 *   as long as users adhere to the convention of registering policies
+	 *   in init() and unregistering them in module exit() functions, there
+	 *   should not be a race between these operations.
+	 * - During any policy-specific lprocfs operations, because a reference
+	 *   is held by the kernel on a proc entry that has been entered by a
+	 *   syscall, so as long as proc entries are removed during
+	 *   unregistration time, then unregistration and lprocfs operations
+	 *   will be properly serialized.
+	 */
+	struct module			       *pd_owner;
+	/**
+	 * Bitmask of \e nrs_policy_flags
+	 */
+	unsigned int				pd_flags;
+	/**
+	 * # of references on this descriptor
+	 */
+	atomic_t				pd_refs;
+};
+
+/**
+ * NRS policy state
+ *
+ * Policies transition from one state to the other during their lifetime
+ */
+enum ptlrpc_nrs_pol_state {
+	/**
+	 * Not a valid policy state.
+	 */
+	NRS_POL_STATE_INVALID,
+	/**
+	 * Policies are at this state either at the start of their life, or
+	 * transition here when the user selects a different policy to act
+	 * as the primary one.
+	 */
+	NRS_POL_STATE_STOPPED,
+	/**
+	 * Policy is progress of stopping
+	 */
+	NRS_POL_STATE_STOPPING,
+	/**
+	 * Policy is in progress of starting
+	 */
+	NRS_POL_STATE_STARTING,
+	/**
+	 * A policy is in this state in two cases:
+	 * - it is the fallback policy, which is always in this state.
+	 * - it has been activated by the user; i.e. it is the primary policy,
+	 */
+	NRS_POL_STATE_STARTED,
+};
+
+/**
+ * NRS policy information
+ *
+ * Used for obtaining information for the status of a policy via lprocfs
+ */
+struct ptlrpc_nrs_pol_info {
+	/**
+	 * Policy name
+	 */
+	char				pi_name[NRS_POL_NAME_MAX];
+	/**
+	 * Policy argument
+	 */
+	char				pi_arg[NRS_POL_ARG_MAX];
+	/**
+	 * Current policy state
+	 */
+	enum ptlrpc_nrs_pol_state	pi_state;
+	/**
+	 * # RPCs enqueued for later dispatching by the policy
+	 */
+	long				pi_req_queued;
+	/**
+	 * # RPCs started for dispatch by the policy
+	 */
+	long				pi_req_started;
+	/**
+	 * Is this a fallback policy?
+	 */
+	unsigned			pi_fallback:1;
+};
+
+/**
+ * NRS policy
+ *
+ * There is one instance of this for each policy in each NRS head of each
+ * PTLRPC service partition.
+ */
+struct ptlrpc_nrs_policy {
+	/**
+	 * Linkage into the NRS head's list of policies,
+	 * ptlrpc_nrs:nrs_policy_list
+	 */
+	struct list_head		pol_list;
+	/**
+	 * Linkage into the NRS head's list of policies with enqueued
+	 * requests ptlrpc_nrs:nrs_policy_queued
+	 */
+	struct list_head		pol_list_queued;
+	/**
+	 * Current state of this policy
+	 */
+	enum ptlrpc_nrs_pol_state	pol_state;
+	/**
+	 * Bitmask of nrs_policy_flags
+	 */
+	unsigned int			pol_flags;
+	/**
+	 * # RPCs enqueued for later dispatching by the policy
+	 */
+	long				pol_req_queued;
+	/**
+	 * # RPCs started for dispatch by the policy
+	 */
+	long				pol_req_started;
+	/**
+	 * Usage Reference count taken on the policy instance
+	 */
+	long				pol_ref;
+	/**
+	 * Human-readable policy argument
+	 */
+	char				pol_arg[NRS_POL_ARG_MAX];
+	/**
+	 * The NRS head this policy has been created at
+	 */
+	struct ptlrpc_nrs	       *pol_nrs;
+	/**
+	 * Private policy data; varies by policy type
+	 */
+	void			       *pol_private;
+	/**
+	 * Policy descriptor for this policy instance.
+	 */
+	struct ptlrpc_nrs_pol_desc     *pol_desc;
+};
+
+/**
+ * NRS resource
+ *
+ * Resources are embedded into two types of NRS entities:
+ * - Inside NRS policies, in the policy's private data in
+ *   ptlrpc_nrs_policy::pol_private
+ * - In objects that act as prime-level scheduling entities in different NRS
+ *   policies; e.g. on a policy that performs round robin or similar order
+ *   scheduling across client NIDs, there would be one NRS resource per unique
+ *   client NID. On a policy which performs round robin scheduling across
+ *   backend filesystem objects, there would be one resource associated with
+ *   each of the backend filesystem objects partaking in the scheduling
+ *   performed by the policy.
+ *
+ * NRS resources share a parent-child relationship, in which resources embedded
+ * in policy instances are the parent entities, with all scheduling entities
+ * a policy schedules across being the children, thus forming a simple resource
+ * hierarchy. This hierarchy may be extended with one or more levels in the
+ * future if the ability to have more than one primary policy is added.
+ *
+ * Upon request initialization, references to the then active NRS policies are
+ * taken and used to later handle the dispatching of the request with one of
+ * these policies.
+ *
+ * \see nrs_resource_get_safe()
+ * \see ptlrpc_nrs_req_add()
+ */
+struct ptlrpc_nrs_resource {
+	/**
+	 * This NRS resource's parent; is NULL for resources embedded in NRS
+	 * policy instances; i.e. those are top-level ones.
+	 */
+	struct ptlrpc_nrs_resource     *res_parent;
+	/**
+	 * The policy associated with this resource.
+	 */
+	struct ptlrpc_nrs_policy       *res_policy;
+};
+
+enum {
+	NRS_RES_FALLBACK,
+	NRS_RES_PRIMARY,
+	NRS_RES_MAX
+};
+
+#include "lustre_nrs_fifo.h"
+
+/**
+ * NRS request
+ *
+ * Instances of this object exist embedded within ptlrpc_request; the main
+ * purpose of this object is to hold references to the request's resources
+ * for the lifetime of the request, and to hold properties that policies use
+ * use for determining the request's scheduling priority.
+ **/
+struct ptlrpc_nrs_request {
+	/**
+	 * The request's resource hierarchy.
+	 */
+	struct ptlrpc_nrs_resource     *nr_res_ptrs[NRS_RES_MAX];
+	/**
+	 * Index into ptlrpc_nrs_request::nr_res_ptrs of the resource of the
+	 * policy that was used to enqueue the request.
+	 *
+	 * \see nrs_request_enqueue()
+	 */
+	unsigned int			nr_res_idx;
+	unsigned int			nr_initialized:1;
+	unsigned int			nr_enqueued:1;
+	unsigned int			nr_started:1;
+	unsigned int			nr_finalized:1;
+
+	/**
+	 * Policy-specific fields, used for determining a request's scheduling
+	 * priority, and other supporting functionality.
+	 */
+	union {
+		/**
+		 * Fields for the FIFO policy
+		 */
+		struct nrs_fifo_req	fifo;
+	} nr_u;
+	/**
+	 * Externally-registering policies may want to use this to allocate
+	 * their own request properties.
+	 */
+	void			       *ext;
+};
+
+/** @} nrs */
+#endif
diff --git a/drivers/staging/lustre/lustre/include/lustre_nrs_fifo.h b/drivers/staging/lustre/lustre/include/lustre_nrs_fifo.h
new file mode 100644
index 0000000..3b5418e
--- /dev/null
+++ b/drivers/staging/lustre/lustre/include/lustre_nrs_fifo.h
@@ -0,0 +1,70 @@
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License version 2 for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.gnu.org/licenses/gpl-2.0.html
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * Copyright 2012 Xyratex Technology Limited
+ */
+/*
+ *
+ * Network Request Scheduler (NRS) First-in First-out (FIFO) policy
+ *
+ */
+
+#ifndef _LUSTRE_NRS_FIFO_H
+#define _LUSTRE_NRS_FIFO_H
+
+/* \name fifo
+ *
+ * FIFO policy
+ *
+ * This policy is a logical wrapper around previous, non-NRS functionality.
+ * It dispatches RPCs in the same order as they arrive from the network. This
+ * policy is currently used as the fallback policy, and the only enabled policy
+ * on all NRS heads of all PTLRPC service partitions.
+ * @{
+ */
+
+/**
+ * Private data structure for the FIFO policy
+ */
+struct nrs_fifo_head {
+	/**
+	 * Resource object for policy instance.
+	 */
+	struct ptlrpc_nrs_resource	fh_res;
+	/**
+	 * List of queued requests.
+	 */
+	struct list_head		fh_list;
+	/**
+	 * For debugging purposes.
+	 */
+	__u64				fh_sequence;
+};
+
+struct nrs_fifo_req {
+	struct list_head	fr_list;
+	__u64			fr_sequence;
+};
+
+/** @} fifo */
+#endif
-- 
1.7.1