// SPDX-License-Identifier: GPL-2.0
/*
 * Author(s)......: Holger Smolinski <Holger.Smolinski@de.ibm.com>
 *                  Horst Hummel <Horst.Hummel@de.ibm.com>
 *                  Carsten Otte <Cotte@de.ibm.com>
 *                  Martin Schwidefsky <schwidefsky@de.ibm.com>
 * Bugreports.to..: <Linux390@de.ibm.com>
 * Copyright IBM Corp. 1999, 2002
 *
 * /proc interface for the dasd driver.
 *
 */

#include <linux/ctype.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/seq_file.h>
#include <linux/vmalloc.h>
#include <linux/proc_fs.h>

#include <asm/debug.h>
#include <linux/uaccess.h>

#include "dasd_int.h"

static struct proc_dir_entry *dasd_proc_root_entry = NULL;
static struct proc_dir_entry *dasd_devices_entry = NULL;
static struct proc_dir_entry *dasd_statistics_entry = NULL;

static int
dasd_devices_show(struct seq_file *m, void *v)
{
        struct dasd_device *device;
        struct dasd_block *block;
        char *substr;

        device = dasd_device_from_devindex((unsigned long) v - 1);
        if (IS_ERR(device))
                return 0;
        if (device->block)
                block = device->block;
        else {
                dasd_put_device(device);
                return 0;
        }
        /* Print device number. */
        seq_printf(m, "%s", dev_name(&device->cdev->dev));
        /* Print discipline string. */
        if (device->discipline != NULL)
                seq_printf(m, "(%s)", device->discipline->name);
        else
                seq_printf(m, "(none)");
        /* Print kdev. */
        if (block->gdp)
                seq_printf(m, " at (%3d:%6d)",
                           MAJOR(disk_devt(block->gdp)),
                           MINOR(disk_devt(block->gdp)));
        else
                seq_printf(m, "  at (???:??????)");
        /* Print device name. */
        if (block->gdp)
                seq_printf(m, " is %-8s", block->gdp->disk_name);
        else
                seq_printf(m, " is ????????");
        /* Print devices features. */
        substr = (device->features & DASD_FEATURE_READONLY) ? "(ro)" : " ";
        seq_printf(m, "%4s: ", substr);
        /* Print device status information. */
        switch (device->state) {
        case DASD_STATE_NEW:
                seq_printf(m, "new");
                break;
        case DASD_STATE_KNOWN:
                seq_printf(m, "detected");
                break;
        case DASD_STATE_BASIC:
                seq_printf(m, "basic");
                break;
        case DASD_STATE_UNFMT:
                seq_printf(m, "unformatted");
                break;
        case DASD_STATE_READY:
        case DASD_STATE_ONLINE:
                seq_printf(m, "active ");
                if (dasd_check_blocksize(block->bp_block))
                        seq_printf(m, "n/f       ");
                else
                        seq_printf(m,
                                   "at blocksize: %u, %lu blocks, %lu MB",
                                   block->bp_block, block->blocks,
                                   ((block->bp_block >> 9) *
                                    block->blocks) >> 11);
                break;
        default:
                seq_printf(m, "no stat");
                break;
        }
        dasd_put_device(device);
        if (dasd_probeonly)
                seq_printf(m, "(probeonly)");
        seq_printf(m, "\n");
        return 0;
}

static void *dasd_devices_start(struct seq_file *m, loff_t *pos)
{
        if (*pos >= dasd_max_devindex)
                return NULL;
        return (void *)((unsigned long) *pos + 1);
}

static void *dasd_devices_next(struct seq_file *m, void *v, loff_t *pos)
{
        ++*pos;
        return dasd_devices_start(m, pos);
}

static void dasd_devices_stop(struct seq_file *m, void *v)
{
}

static const struct seq_operations dasd_devices_seq_ops = {
        .start          = dasd_devices_start,
        .next           = dasd_devices_next,
        .stop           = dasd_devices_stop,
        .show           = dasd_devices_show,
};

#ifdef CONFIG_DASD_PROFILE
static int dasd_stats_all_block_on(void)
{
        int i, rc;
        struct dasd_device *device;

        rc = 0;
        for (i = 0; i < dasd_max_devindex; ++i) {
                device = dasd_device_from_devindex(i);
                if (IS_ERR(device))
                        continue;
                if (device->block)
                        rc = dasd_profile_on(&device->block->profile);
                dasd_put_device(device);
                if (rc)
                        return rc;
        }
        return 0;
}

static void dasd_stats_all_block_off(void)
{
        int i;
        struct dasd_device *device;

        for (i = 0; i < dasd_max_devindex; ++i) {
                device = dasd_device_from_devindex(i);
                if (IS_ERR(device))
                        continue;
                if (device->block)
                        dasd_profile_off(&device->block->profile);
                dasd_put_device(device);
        }
}

static void dasd_stats_all_block_reset(void)
{
        int i;
        struct dasd_device *device;

        for (i = 0; i < dasd_max_devindex; ++i) {
                device = dasd_device_from_devindex(i);
                if (IS_ERR(device))
                        continue;
                if (device->block)
                        dasd_profile_reset(&device->block->profile);
                dasd_put_device(device);
        }
}

static void dasd_statistics_array(struct seq_file *m, unsigned int *array, int factor)
{
        int i;

        for (i = 0; i < 32; i++) {
                seq_printf(m, "%7d ", array[i] / factor);
                if (i == 15)
                        seq_putc(m, '\n');
        }
        seq_putc(m, '\n');
}
#endif /* CONFIG_DASD_PROFILE */

static int dasd_stats_proc_show(struct seq_file *m, void *v)
{
#ifdef CONFIG_DASD_PROFILE
        struct dasd_profile_info *prof;
        int factor;

        spin_lock_bh(&dasd_global_profile.lock);
        prof = dasd_global_profile.data;
        if (!prof) {
                spin_unlock_bh(&dasd_global_profile.lock);
                seq_printf(m, "Statistics are off - they might be "
                                    "switched on using 'echo set on > "
                                    "/proc/dasd/statistics'\n");
                return 0;
        }

        /* prevent counter 'overflow' on output */
        for (factor = 1; (prof->dasd_io_reqs / factor) > 9999999;
             factor *= 10);

        seq_printf(m, "%d dasd I/O requests\n", prof->dasd_io_reqs);
        seq_printf(m, "with %u sectors(512B each)\n",
                       prof->dasd_io_sects);
        seq_printf(m, "Scale Factor is  %d\n", factor);
        seq_printf(m,
                       "   __<4    ___8    __16    __32    __64    _128 "
                       "   _256    _512    __1k    __2k    __4k    __8k "
                       "   _16k    _32k    _64k    128k\n");
        seq_printf(m,
                       "   _256    _512    __1M    __2M    __4M    __8M "
                       "   _16M    _32M    _64M    128M    256M    512M "
                       "   __1G    __2G    __4G " "   _>4G\n");

        seq_printf(m, "Histogram of sizes (512B secs)\n");
        dasd_statistics_array(m, prof->dasd_io_secs, factor);
        seq_printf(m, "Histogram of I/O times (microseconds)\n");
        dasd_statistics_array(m, prof->dasd_io_times, factor);
        seq_printf(m, "Histogram of I/O times per sector\n");
        dasd_statistics_array(m, prof->dasd_io_timps, factor);
        seq_printf(m, "Histogram of I/O time till ssch\n");
        dasd_statistics_array(m, prof->dasd_io_time1, factor);
        seq_printf(m, "Histogram of I/O time between ssch and irq\n");
        dasd_statistics_array(m, prof->dasd_io_time2, factor);
        seq_printf(m, "Histogram of I/O time between ssch "
                            "and irq per sector\n");
        dasd_statistics_array(m, prof->dasd_io_time2ps, factor);
        seq_printf(m, "Histogram of I/O time between irq and end\n");
        dasd_statistics_array(m, prof->dasd_io_time3, factor);
        seq_printf(m, "# of req in chanq at enqueuing (1..32) \n");
        dasd_statistics_array(m, prof->dasd_io_nr_req, factor);
        spin_unlock_bh(&dasd_global_profile.lock);
#else
        seq_printf(m, "Statistics are not activated in this kernel\n");
#endif
        return 0;
}

static int dasd_stats_proc_open(struct inode *inode, struct file *file)
{
        return single_open(file, dasd_stats_proc_show, NULL);
}

static ssize_t dasd_stats_proc_write(struct file *file,
                const char __user *user_buf, size_t user_len, loff_t *pos)
{
#ifdef CONFIG_DASD_PROFILE
        char *buffer, *str;
        int rc;

        if (user_len > 65536)
                user_len = 65536;
        buffer = dasd_get_user_string(user_buf, user_len);
        if (IS_ERR(buffer))
                return PTR_ERR(buffer);

        /* check for valid verbs */
        str = skip_spaces(buffer);
        if (strncmp(str, "set", 3) == 0 && isspace(str[3])) {
                /* 'set xxx' was given */
                str = skip_spaces(str + 4);
                if (strcmp(str, "on") == 0) {
                        /* switch on statistics profiling */
                        rc = dasd_stats_all_block_on();
                        if (rc) {
                                dasd_stats_all_block_off();
                                goto out_error;
                        }
                        rc = dasd_profile_on(&dasd_global_profile);
                        if (rc) {
                                dasd_stats_all_block_off();
                                goto out_error;
                        }
                        dasd_profile_reset(&dasd_global_profile);
                        dasd_global_profile_level = DASD_PROFILE_ON;
                        pr_info("The statistics feature has been switched "
                                "on\n");
                } else if (strcmp(str, "off") == 0) {
                        /* switch off statistics profiling */
                        dasd_global_profile_level = DASD_PROFILE_OFF;
                        dasd_profile_off(&dasd_global_profile);
                        dasd_stats_all_block_off();
                        pr_info("The statistics feature has been switched "
                                "off\n");
                } else
                        goto out_parse_error;
        } else if (strncmp(str, "reset", 5) == 0) {
                /* reset the statistics */
                dasd_profile_reset(&dasd_global_profile);
                dasd_stats_all_block_reset();
                pr_info("The statistics have been reset\n");
        } else
                goto out_parse_error;
        vfree(buffer);
        return user_len;
out_parse_error:
        rc = -EINVAL;
        pr_warn("%s is not a supported value for /proc/dasd/statistics\n", str);
out_error:
        vfree(buffer);
        return rc;
#else
        pr_warn("/proc/dasd/statistics: is not activated in this kernel\n");
        return user_len;
#endif                          /* CONFIG_DASD_PROFILE */
}

static const struct proc_ops dasd_stats_proc_ops = {
        .proc_open      = dasd_stats_proc_open,
        .proc_read      = seq_read,
        .proc_lseek     = seq_lseek,
        .proc_release   = single_release,
        .proc_write     = dasd_stats_proc_write,
};

/*
 * Create dasd proc-fs entries.
 * In case creation failed, cleanup and return -ENOENT.
 */
int
dasd_proc_init(void)
{
        dasd_proc_root_entry = proc_mkdir("dasd", NULL);
        if (!dasd_proc_root_entry)
                goto out_nodasd;
        dasd_devices_entry = proc_create_seq("devices", 0444,
                                         dasd_proc_root_entry,
                                         &dasd_devices_seq_ops);
        if (!dasd_devices_entry)
                goto out_nodevices;
        dasd_statistics_entry = proc_create("statistics",
                                            S_IFREG | S_IRUGO | S_IWUSR,
                                            dasd_proc_root_entry,
                                            &dasd_stats_proc_ops);
        if (!dasd_statistics_entry)
                goto out_nostatistics;
        return 0;

 out_nostatistics:
        remove_proc_entry("devices", dasd_proc_root_entry);
 out_nodevices:
        remove_proc_entry("dasd", NULL);
        dasd_proc_root_entry = NULL;
 out_nodasd:
        return -ENOENT;
}

void
dasd_proc_exit(void)
{
        if (!dasd_proc_root_entry)
                return;

        remove_proc_entry("devices", dasd_proc_root_entry);
        remove_proc_entry("statistics", dasd_proc_root_entry);
        remove_proc_entry("dasd", NULL);
        dasd_proc_root_entry = NULL;
}