SmartAudio/lichee/linux-4.9/drivers/gator/gator_events_block.c

/**
 * Copyright (C) ARM Limited 2010-2016. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include "gator.h"
#include <trace/events/block.h>

#define BLOCK_RQ_WR     0
#define BLOCK_RQ_RD     1

#define BLOCK_TOTAL     (BLOCK_RQ_RD+1)

#if LINUX_VERSION_CODE < KERNEL_VERSION(4, 8, 0)
#define GATOR_REQ_IS_OP_WRITE(rq)   (rq->cmd_flags & REQ_WRITE)
#else
#define GATOR_REQ_IS_OP_WRITE(rq)   (req_op(rq) & REQ_OP_WRITE)
#endif

static ulong block_rq_wr_enabled;
static ulong block_rq_rd_enabled;
static ulong block_rq_wr_key;
static ulong block_rq_rd_key;
static atomic_t blockCnt[BLOCK_TOTAL];
static int blockGet[BLOCK_TOTAL * 4];

/* Tracepoint changed in 3.15 backported to older kernels. The Makefile tries to autodetect the correct value, but if it fails change the #if below */
#if OLD_BLOCK_RQ_COMPLETE
GATOR_DEFINE_PROBE(block_rq_complete, TP_PROTO(struct request_queue *q, struct request *rq))
#else
GATOR_DEFINE_PROBE(block_rq_complete, TP_PROTO(struct request_queue *q, struct request *rq, unsigned int nr_bytes))
#endif
{
    int write;
    unsigned int size;

    if (!rq)
        return;

    write = GATOR_REQ_IS_OP_WRITE(rq);

#if OLD_BLOCK_RQ_COMPLETE
    size = rq->resid_len;
#else
    size = nr_bytes;
#endif

    if (!size)
        return;

    if (write) {
        if (block_rq_wr_enabled)
            atomic_add(size, &blockCnt[BLOCK_RQ_WR]);
    } else {
        if (block_rq_rd_enabled)
            atomic_add(size, &blockCnt[BLOCK_RQ_RD]);
    }
}

static int gator_events_block_create_files(struct super_block *sb, struct dentry *root)
{
    struct dentry *dir;

    /* block_complete_wr */
    dir = gatorfs_mkdir(sb, root, "Linux_block_rq_wr");
    if (!dir)
        return -1;
    gatorfs_create_ulong(sb, dir, "enabled", &block_rq_wr_enabled);
    gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_wr_key);

    /* block_complete_rd */
    dir = gatorfs_mkdir(sb, root, "Linux_block_rq_rd");
    if (!dir)
        return -1;
    gatorfs_create_ulong(sb, dir, "enabled", &block_rq_rd_enabled);
    gatorfs_create_ro_ulong(sb, dir, "key", &block_rq_rd_key);

    return 0;
}

static int gator_events_block_start(void)
{
    /* register tracepoints */
    if (block_rq_wr_enabled || block_rq_rd_enabled)
        if (GATOR_REGISTER_TRACE(block_rq_complete))
            goto fail_block_rq_exit;
    pr_debug("gator: registered block event tracepoints\n");

    return 0;

    /* unregister tracepoints on error */
fail_block_rq_exit:
    pr_err("gator: block event tracepoints failed to activate, please verify that tracepoints are enabled in the linux kernel\n");

    return -1;
}

static void gator_events_block_stop(void)
{
    if (block_rq_wr_enabled || block_rq_rd_enabled)
        GATOR_UNREGISTER_TRACE(block_rq_complete);
    pr_debug("gator: unregistered block event tracepoints\n");

    block_rq_wr_enabled = 0;
    block_rq_rd_enabled = 0;
}

static int gator_events_block_read(int **buffer, bool sched_switch)
{
    int len, value, data = 0;

    if (!on_primary_core())
        return 0;

    len = 0;
    if (block_rq_wr_enabled && (value = atomic_read(&blockCnt[BLOCK_RQ_WR])) > 0) {
        atomic_sub(value, &blockCnt[BLOCK_RQ_WR]);
        blockGet[len++] = block_rq_wr_key;
        /* Indicates to Streamline that value bytes were written now, not since the last message */
        blockGet[len++] = 0;
        blockGet[len++] = block_rq_wr_key;
        blockGet[len++] = value;
        data += value;
    }
    if (block_rq_rd_enabled && (value = atomic_read(&blockCnt[BLOCK_RQ_RD])) > 0) {
        atomic_sub(value, &blockCnt[BLOCK_RQ_RD]);
        blockGet[len++] = block_rq_rd_key;
        /* Indicates to Streamline that value bytes were read now, not since the last message */
        blockGet[len++] = 0;
        blockGet[len++] = block_rq_rd_key;
        blockGet[len++] = value;
        data += value;
    }

    if (buffer)
        *buffer = blockGet;

    return len;
}

static struct gator_interface gator_events_block_interface = {
    .name = "block",
    .create_files = gator_events_block_create_files,
    .start = gator_events_block_start,
    .stop = gator_events_block_stop,
    .read = gator_events_block_read,
};

int gator_events_block_init(void)
{
    block_rq_wr_enabled = 0;
    block_rq_rd_enabled = 0;

    block_rq_wr_key = gator_events_get_key();
    block_rq_rd_key = gator_events_get_key();

    return gator_events_install(&gator_events_block_interface);
}