458 lines
10 KiB
C
458 lines
10 KiB
C
/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
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/*
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* Copyright(c) 2015 - 2018 Intel Corporation.
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*/
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#ifndef _HFI1_IOWAIT_H
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#define _HFI1_IOWAIT_H
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <linux/wait.h>
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#include <linux/sched.h>
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#include "sdma_txreq.h"
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/*
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* typedef (*restart_t)() - restart callback
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* @work: pointer to work structure
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*/
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typedef void (*restart_t)(struct work_struct *work);
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#define IOWAIT_PENDING_IB 0x0
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#define IOWAIT_PENDING_TID 0x1
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/*
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* A QP can have multiple Send Engines (SEs).
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*
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* The current use case is for supporting a TID RDMA
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* packet build/xmit mechanism independent from verbs.
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*/
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#define IOWAIT_SES 2
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#define IOWAIT_IB_SE 0
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#define IOWAIT_TID_SE 1
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struct sdma_txreq;
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struct sdma_engine;
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/**
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* @iowork: the work struct
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* @tx_head: list of prebuilt packets
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* @iow: the parent iowait structure
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*
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* This structure is the work item (process) specific
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* details associated with the each of the two SEs of the
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* QP.
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*
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* The workstruct and the queued TXs are unique to each
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* SE.
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*/
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struct iowait;
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struct iowait_work {
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struct work_struct iowork;
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struct list_head tx_head;
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struct iowait *iow;
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};
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/**
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* @list: used to add/insert into QP/PQ wait lists
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* @tx_head: overflow list of sdma_txreq's
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* @sleep: no space callback
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* @wakeup: space callback wakeup
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* @sdma_drained: sdma count drained
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* @init_priority: callback to manipulate priority
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* @lock: lock protected head of wait queue
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* @iowork: workqueue overhead
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* @wait_dma: wait for sdma_busy == 0
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* @wait_pio: wait for pio_busy == 0
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* @sdma_busy: # of packets in flight
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* @count: total number of descriptors in tx_head'ed list
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* @tx_limit: limit for overflow queuing
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* @tx_count: number of tx entry's in tx_head'ed list
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* @flags: wait flags (one per QP)
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* @wait: SE array for multiple legs
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*
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* This is to be embedded in user's state structure
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* (QP or PQ).
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*
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* The sleep and wakeup members are a
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* bit misnamed. They do not strictly
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* speaking sleep or wake up, but they
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* are callbacks for the ULP to implement
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* what ever queuing/dequeuing of
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* the embedded iowait and its containing struct
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* when a resource shortage like SDMA ring space
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* or PIO credit space is seen.
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*
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* Both potentially have locks help
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* so sleeping is not allowed and it is not
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* supported to submit txreqs from the wakeup
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* call directly because of lock conflicts.
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*
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* The wait_dma member along with the iow
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*
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* The lock field is used by waiters to record
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* the seqlock_t that guards the list head.
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* Waiters explicity know that, but the destroy
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* code that unwaits QPs does not.
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*/
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struct iowait {
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struct list_head list;
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int (*sleep)(
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struct sdma_engine *sde,
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struct iowait_work *wait,
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struct sdma_txreq *tx,
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uint seq,
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bool pkts_sent
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);
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void (*wakeup)(struct iowait *wait, int reason);
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void (*sdma_drained)(struct iowait *wait);
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void (*init_priority)(struct iowait *wait);
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seqlock_t *lock;
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wait_queue_head_t wait_dma;
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wait_queue_head_t wait_pio;
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atomic_t sdma_busy;
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atomic_t pio_busy;
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u32 count;
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u32 tx_limit;
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u32 tx_count;
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u8 starved_cnt;
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u8 priority;
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unsigned long flags;
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struct iowait_work wait[IOWAIT_SES];
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};
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#define SDMA_AVAIL_REASON 0
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void iowait_set_flag(struct iowait *wait, u32 flag);
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bool iowait_flag_set(struct iowait *wait, u32 flag);
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void iowait_clear_flag(struct iowait *wait, u32 flag);
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void iowait_init(struct iowait *wait, u32 tx_limit,
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void (*func)(struct work_struct *work),
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void (*tidfunc)(struct work_struct *work),
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int (*sleep)(struct sdma_engine *sde,
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struct iowait_work *wait,
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struct sdma_txreq *tx,
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uint seq,
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bool pkts_sent),
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void (*wakeup)(struct iowait *wait, int reason),
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void (*sdma_drained)(struct iowait *wait),
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void (*init_priority)(struct iowait *wait));
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/**
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* iowait_schedule() - schedule the default send engine work
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* @wait: wait struct to schedule
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* @wq: workqueue for schedule
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* @cpu: cpu
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*/
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static inline bool iowait_schedule(struct iowait *wait,
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struct workqueue_struct *wq, int cpu)
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{
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return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_IB_SE].iowork);
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}
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/**
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* iowait_tid_schedule - schedule the tid SE
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* @wait: the iowait structure
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* @wq: the work queue
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* @cpu: the cpu
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*/
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static inline bool iowait_tid_schedule(struct iowait *wait,
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struct workqueue_struct *wq, int cpu)
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{
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return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_TID_SE].iowork);
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}
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/**
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* iowait_sdma_drain() - wait for DMAs to drain
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*
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* @wait: iowait structure
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*
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* This will delay until the iowait sdmas have
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* completed.
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*/
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static inline void iowait_sdma_drain(struct iowait *wait)
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{
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wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
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}
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/**
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* iowait_sdma_pending() - return sdma pending count
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*
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* @wait: iowait structure
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*
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*/
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static inline int iowait_sdma_pending(struct iowait *wait)
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{
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return atomic_read(&wait->sdma_busy);
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}
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/**
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* iowait_sdma_inc - note sdma io pending
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* @wait: iowait structure
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*/
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static inline void iowait_sdma_inc(struct iowait *wait)
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{
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atomic_inc(&wait->sdma_busy);
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}
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/**
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* iowait_sdma_add - add count to pending
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* @wait: iowait structure
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*/
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static inline void iowait_sdma_add(struct iowait *wait, int count)
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{
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atomic_add(count, &wait->sdma_busy);
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}
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/**
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* iowait_sdma_dec - note sdma complete
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* @wait: iowait structure
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*/
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static inline int iowait_sdma_dec(struct iowait *wait)
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{
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if (!wait)
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return 0;
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return atomic_dec_and_test(&wait->sdma_busy);
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}
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/**
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* iowait_pio_drain() - wait for pios to drain
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*
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* @wait: iowait structure
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*
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* This will delay until the iowait pios have
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* completed.
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*/
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static inline void iowait_pio_drain(struct iowait *wait)
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{
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wait_event_timeout(wait->wait_pio,
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!atomic_read(&wait->pio_busy),
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HZ);
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}
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/**
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* iowait_pio_pending() - return pio pending count
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*
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* @wait: iowait structure
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*
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*/
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static inline int iowait_pio_pending(struct iowait *wait)
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{
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return atomic_read(&wait->pio_busy);
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}
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/**
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* iowait_pio_inc - note pio pending
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* @wait: iowait structure
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*/
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static inline void iowait_pio_inc(struct iowait *wait)
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{
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atomic_inc(&wait->pio_busy);
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}
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/**
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* iowait_pio_dec - note pio complete
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* @wait: iowait structure
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*/
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static inline int iowait_pio_dec(struct iowait *wait)
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{
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if (!wait)
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return 0;
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return atomic_dec_and_test(&wait->pio_busy);
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}
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/**
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* iowait_drain_wakeup() - trigger iowait_drain() waiter
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*
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* @wait: iowait structure
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*
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* This will trigger any waiters.
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*/
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static inline void iowait_drain_wakeup(struct iowait *wait)
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{
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wake_up(&wait->wait_dma);
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wake_up(&wait->wait_pio);
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if (wait->sdma_drained)
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wait->sdma_drained(wait);
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}
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/**
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* iowait_get_txhead() - get packet off of iowait list
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*
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* @wait: iowait_work structure
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*/
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static inline struct sdma_txreq *iowait_get_txhead(struct iowait_work *wait)
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{
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struct sdma_txreq *tx = NULL;
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if (!list_empty(&wait->tx_head)) {
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tx = list_first_entry(
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&wait->tx_head,
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struct sdma_txreq,
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list);
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list_del_init(&tx->list);
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}
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return tx;
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}
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static inline u16 iowait_get_desc(struct iowait_work *w)
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{
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u16 num_desc = 0;
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struct sdma_txreq *tx = NULL;
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if (!list_empty(&w->tx_head)) {
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tx = list_first_entry(&w->tx_head, struct sdma_txreq,
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list);
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num_desc = tx->num_desc;
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if (tx->flags & SDMA_TXREQ_F_VIP)
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w->iow->priority++;
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}
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return num_desc;
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}
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static inline u32 iowait_get_all_desc(struct iowait *w)
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{
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u32 num_desc = 0;
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num_desc = iowait_get_desc(&w->wait[IOWAIT_IB_SE]);
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num_desc += iowait_get_desc(&w->wait[IOWAIT_TID_SE]);
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return num_desc;
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}
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static inline void iowait_update_priority(struct iowait_work *w)
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{
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struct sdma_txreq *tx = NULL;
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if (!list_empty(&w->tx_head)) {
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tx = list_first_entry(&w->tx_head, struct sdma_txreq,
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list);
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if (tx->flags & SDMA_TXREQ_F_VIP)
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w->iow->priority++;
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}
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}
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static inline void iowait_update_all_priority(struct iowait *w)
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{
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iowait_update_priority(&w->wait[IOWAIT_IB_SE]);
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iowait_update_priority(&w->wait[IOWAIT_TID_SE]);
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}
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static inline void iowait_init_priority(struct iowait *w)
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{
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w->priority = 0;
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if (w->init_priority)
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w->init_priority(w);
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}
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static inline void iowait_get_priority(struct iowait *w)
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{
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iowait_init_priority(w);
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iowait_update_all_priority(w);
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}
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/**
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* iowait_queue - Put the iowait on a wait queue
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* @pkts_sent: have some packets been sent before queuing?
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* @w: the iowait struct
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* @wait_head: the wait queue
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*
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* This function is called to insert an iowait struct into a
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* wait queue after a resource (eg, sdma descriptor or pio
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* buffer) is run out.
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*/
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static inline void iowait_queue(bool pkts_sent, struct iowait *w,
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struct list_head *wait_head)
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{
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/*
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* To play fair, insert the iowait at the tail of the wait queue if it
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* has already sent some packets; Otherwise, put it at the head.
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* However, if it has priority packets to send, also put it at the
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* head.
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*/
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if (pkts_sent)
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w->starved_cnt = 0;
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else
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w->starved_cnt++;
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if (w->priority > 0 || !pkts_sent)
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list_add(&w->list, wait_head);
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else
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list_add_tail(&w->list, wait_head);
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}
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/**
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* iowait_starve_clear - clear the wait queue's starve count
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* @pkts_sent: have some packets been sent?
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* @w: the iowait struct
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*
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* This function is called to clear the starve count. If no
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* packets have been sent, the starve count will not be cleared.
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*/
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static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
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{
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if (pkts_sent)
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w->starved_cnt = 0;
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}
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/* Update the top priority index */
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uint iowait_priority_update_top(struct iowait *w,
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struct iowait *top,
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uint idx, uint top_idx);
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/**
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* iowait_packet_queued() - determine if a packet is queued
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* @wait: the iowait_work structure
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*/
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static inline bool iowait_packet_queued(struct iowait_work *wait)
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{
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return !list_empty(&wait->tx_head);
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}
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/**
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* inc_wait_count - increment wait counts
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* @w: the log work struct
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* @n: the count
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*/
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static inline void iowait_inc_wait_count(struct iowait_work *w, u16 n)
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{
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if (!w)
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return;
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w->iow->tx_count++;
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w->iow->count += n;
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}
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/**
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* iowait_get_tid_work - return iowait_work for tid SE
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* @w: the iowait struct
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*/
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static inline struct iowait_work *iowait_get_tid_work(struct iowait *w)
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{
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return &w->wait[IOWAIT_TID_SE];
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}
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/**
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* iowait_get_ib_work - return iowait_work for ib SE
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* @w: the iowait struct
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*/
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static inline struct iowait_work *iowait_get_ib_work(struct iowait *w)
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{
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return &w->wait[IOWAIT_IB_SE];
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}
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/**
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* iowait_ioww_to_iow - return iowait given iowait_work
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* @w: the iowait_work struct
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*/
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static inline struct iowait *iowait_ioww_to_iow(struct iowait_work *w)
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{
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if (likely(w))
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return w->iow;
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return NULL;
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}
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void iowait_cancel_work(struct iowait *w);
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int iowait_set_work_flag(struct iowait_work *w);
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#endif
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