NVMe: Implement namespace list scanning

[deliverable/linux.git] / drivers / nvme / host / core.c

/*
 * NVM Express device driver
 * Copyright (c) 2011-2014, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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 for
 * more details.
 */

#include <linux/blkdev.h>
#include <linux/blk-mq.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/hdreg.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list_sort.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/pr.h>
#include <linux/ptrace.h>
#include <linux/nvme_ioctl.h>
#include <linux/t10-pi.h>
#include <scsi/sg.h>
#include <asm/unaligned.h>

#include "nvme.h"

#define NVME_MINORS             (1U << MINORBITS)

static int nvme_major;
module_param(nvme_major, int, 0);

static int nvme_char_major;
module_param(nvme_char_major, int, 0);

static LIST_HEAD(nvme_ctrl_list);
DEFINE_SPINLOCK(dev_list_lock);

static struct class *nvme_class;

static void nvme_free_ns(struct kref *kref)
{
        struct nvme_ns *ns = container_of(kref, struct nvme_ns, kref);

        if (ns->type == NVME_NS_LIGHTNVM)
                nvme_nvm_unregister(ns->queue, ns->disk->disk_name);

        spin_lock(&dev_list_lock);
        ns->disk->private_data = NULL;
        spin_unlock(&dev_list_lock);

        nvme_put_ctrl(ns->ctrl);
        put_disk(ns->disk);
        kfree(ns);
}

static void nvme_put_ns(struct nvme_ns *ns)
{
        kref_put(&ns->kref, nvme_free_ns);
}

static struct nvme_ns *nvme_get_ns_from_disk(struct gendisk *disk)
{
        struct nvme_ns *ns;

        spin_lock(&dev_list_lock);
        ns = disk->private_data;
        if (ns && !kref_get_unless_zero(&ns->kref))
                ns = NULL;
        spin_unlock(&dev_list_lock);

        return ns;
}

struct request *nvme_alloc_request(struct request_queue *q,
                struct nvme_command *cmd, unsigned int flags)
{
        bool write = cmd->common.opcode & 1;
        struct request *req;

        req = blk_mq_alloc_request(q, write, flags);
        if (IS_ERR(req))
                return req;

        req->cmd_type = REQ_TYPE_DRV_PRIV;
        req->cmd_flags |= REQ_FAILFAST_DRIVER;
        req->__data_len = 0;
        req->__sector = (sector_t) -1;
        req->bio = req->biotail = NULL;

        req->cmd = (unsigned char *)cmd;
        req->cmd_len = sizeof(struct nvme_command);
        req->special = (void *)0;

        return req;
}

/*
 * Returns 0 on success.  If the result is negative, it's a Linux error code;
 * if the result is positive, it's an NVM Express status code
 */
int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
                void *buffer, unsigned bufflen, u32 *result, unsigned timeout)
{
        struct request *req;
        int ret;

        req = nvme_alloc_request(q, cmd, 0);
        if (IS_ERR(req))
                return PTR_ERR(req);

        req->timeout = timeout ? timeout : ADMIN_TIMEOUT;

        if (buffer && bufflen) {
                ret = blk_rq_map_kern(q, req, buffer, bufflen, GFP_KERNEL);
                if (ret)
                        goto out;
        }

        blk_execute_rq(req->q, NULL, req, 0);
        if (result)
                *result = (u32)(uintptr_t)req->special;
        ret = req->errors;
 out:
        blk_mq_free_request(req);
        return ret;
}

int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
                void *buffer, unsigned bufflen)
{
        return __nvme_submit_sync_cmd(q, cmd, buffer, bufflen, NULL, 0);
}

int __nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
                void __user *ubuffer, unsigned bufflen,
                void __user *meta_buffer, unsigned meta_len, u32 meta_seed,
                u32 *result, unsigned timeout)
{
        bool write = cmd->common.opcode & 1;
        struct nvme_ns *ns = q->queuedata;
        struct gendisk *disk = ns ? ns->disk : NULL;
        struct request *req;
        struct bio *bio = NULL;
        void *meta = NULL;
        int ret;

        req = nvme_alloc_request(q, cmd, 0);
        if (IS_ERR(req))
                return PTR_ERR(req);

        req->timeout = timeout ? timeout : ADMIN_TIMEOUT;

        if (ubuffer && bufflen) {
                ret = blk_rq_map_user(q, req, NULL, ubuffer, bufflen,
                                GFP_KERNEL);
                if (ret)
                        goto out;
                bio = req->bio;

                if (!disk)
                        goto submit;
                bio->bi_bdev = bdget_disk(disk, 0);
                if (!bio->bi_bdev) {
                        ret = -ENODEV;
                        goto out_unmap;
                }

                if (meta_buffer) {
                        struct bio_integrity_payload *bip;

                        meta = kmalloc(meta_len, GFP_KERNEL);
                        if (!meta) {
                                ret = -ENOMEM;
                                goto out_unmap;
                        }

                        if (write) {
                                if (copy_from_user(meta, meta_buffer,
                                                meta_len)) {
                                        ret = -EFAULT;
                                        goto out_free_meta;
                                }
                        }

                        bip = bio_integrity_alloc(bio, GFP_KERNEL, 1);
                        if (IS_ERR(bip)) {
                                ret = PTR_ERR(bip);
                                goto out_free_meta;
                        }

                        bip->bip_iter.bi_size = meta_len;
                        bip->bip_iter.bi_sector = meta_seed;

                        ret = bio_integrity_add_page(bio, virt_to_page(meta),
                                        meta_len, offset_in_page(meta));
                        if (ret != meta_len) {
                                ret = -ENOMEM;
                                goto out_free_meta;
                        }
                }
        }
 submit:
        blk_execute_rq(req->q, disk, req, 0);
        ret = req->errors;
        if (result)
                *result = (u32)(uintptr_t)req->special;
        if (meta && !ret && !write) {
                if (copy_to_user(meta_buffer, meta, meta_len))
                        ret = -EFAULT;
        }
 out_free_meta:
        kfree(meta);
 out_unmap:
        if (bio) {
                if (disk && bio->bi_bdev)
                        bdput(bio->bi_bdev);
                blk_rq_unmap_user(bio);
        }
 out:
        blk_mq_free_request(req);
        return ret;
}

int nvme_submit_user_cmd(struct request_queue *q, struct nvme_command *cmd,
                void __user *ubuffer, unsigned bufflen, u32 *result,
                unsigned timeout)
{
        return __nvme_submit_user_cmd(q, cmd, ubuffer, bufflen, NULL, 0, 0,
                        result, timeout);
}

int nvme_identify_ctrl(struct nvme_ctrl *dev, struct nvme_id_ctrl **id)
{
        struct nvme_command c = { };
        int error;

        /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
        c.identify.opcode = nvme_admin_identify;
        c.identify.cns = cpu_to_le32(1);

        *id = kmalloc(sizeof(struct nvme_id_ctrl), GFP_KERNEL);
        if (!*id)
                return -ENOMEM;

        error = nvme_submit_sync_cmd(dev->admin_q, &c, *id,
                        sizeof(struct nvme_id_ctrl));
        if (error)
                kfree(*id);
        return error;
}

static int nvme_identify_ns_list(struct nvme_ctrl *dev, unsigned nsid, __le32 *ns_list)
{
        struct nvme_command c = { };

        c.identify.opcode = nvme_admin_identify;
        c.identify.cns = cpu_to_le32(2);
        c.identify.nsid = cpu_to_le32(nsid);
        return nvme_submit_sync_cmd(dev->admin_q, &c, ns_list, 0x1000);
}

int nvme_identify_ns(struct nvme_ctrl *dev, unsigned nsid,
                struct nvme_id_ns **id)
{
        struct nvme_command c = { };
        int error;

        /* gcc-4.4.4 (at least) has issues with initializers and anon unions */
        c.identify.opcode = nvme_admin_identify,
        c.identify.nsid = cpu_to_le32(nsid),

        *id = kmalloc(sizeof(struct nvme_id_ns), GFP_KERNEL);
        if (!*id)
                return -ENOMEM;

        error = nvme_submit_sync_cmd(dev->admin_q, &c, *id,
                        sizeof(struct nvme_id_ns));
        if (error)
                kfree(*id);
        return error;
}

int nvme_get_features(struct nvme_ctrl *dev, unsigned fid, unsigned nsid,
                                        dma_addr_t dma_addr, u32 *result)
{
        struct nvme_command c;

        memset(&c, 0, sizeof(c));
        c.features.opcode = nvme_admin_get_features;
        c.features.nsid = cpu_to_le32(nsid);
        c.features.prp1 = cpu_to_le64(dma_addr);
        c.features.fid = cpu_to_le32(fid);

        return __nvme_submit_sync_cmd(dev->admin_q, &c, NULL, 0, result, 0);
}

int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword11,
                                        dma_addr_t dma_addr, u32 *result)
{
        struct nvme_command c;

        memset(&c, 0, sizeof(c));
        c.features.opcode = nvme_admin_set_features;
        c.features.prp1 = cpu_to_le64(dma_addr);
        c.features.fid = cpu_to_le32(fid);
        c.features.dword11 = cpu_to_le32(dword11);

        return __nvme_submit_sync_cmd(dev->admin_q, &c, NULL, 0, result, 0);
}

int nvme_get_log_page(struct nvme_ctrl *dev, struct nvme_smart_log **log)
{
        struct nvme_command c = { };
        int error;

        c.common.opcode = nvme_admin_get_log_page,
        c.common.nsid = cpu_to_le32(0xFFFFFFFF),
        c.common.cdw10[0] = cpu_to_le32(
                        (((sizeof(struct nvme_smart_log) / 4) - 1) << 16) |
                         NVME_LOG_SMART),

        *log = kmalloc(sizeof(struct nvme_smart_log), GFP_KERNEL);
        if (!*log)
                return -ENOMEM;

        error = nvme_submit_sync_cmd(dev->admin_q, &c, *log,
                        sizeof(struct nvme_smart_log));
        if (error)
                kfree(*log);
        return error;
}

int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count)
{
        u32 q_count = (*count - 1) | ((*count - 1) << 16);
        u32 result;
        int status, nr_io_queues;

        status = nvme_set_features(ctrl, NVME_FEAT_NUM_QUEUES, q_count, 0,
                        &result);
        if (status)
                return status;

        nr_io_queues = min(result & 0xffff, result >> 16) + 1;
        *count = min(*count, nr_io_queues);
        return 0;
}

static int nvme_submit_io(struct nvme_ns *ns, struct nvme_user_io __user *uio)
{
        struct nvme_user_io io;
        struct nvme_command c;
        unsigned length, meta_len;
        void __user *metadata;

        if (copy_from_user(&io, uio, sizeof(io)))
                return -EFAULT;

        switch (io.opcode) {
        case nvme_cmd_write:
        case nvme_cmd_read:
        case nvme_cmd_compare:
                break;
        default:
                return -EINVAL;
        }

        length = (io.nblocks + 1) << ns->lba_shift;
        meta_len = (io.nblocks + 1) * ns->ms;
        metadata = (void __user *)(uintptr_t)io.metadata;

        if (ns->ext) {
                length += meta_len;
                meta_len = 0;
        } else if (meta_len) {
                if ((io.metadata & 3) || !io.metadata)
                        return -EINVAL;
        }

        memset(&c, 0, sizeof(c));
        c.rw.opcode = io.opcode;
        c.rw.flags = io.flags;
        c.rw.nsid = cpu_to_le32(ns->ns_id);
        c.rw.slba = cpu_to_le64(io.slba);
        c.rw.length = cpu_to_le16(io.nblocks);
        c.rw.control = cpu_to_le16(io.control);
        c.rw.dsmgmt = cpu_to_le32(io.dsmgmt);
        c.rw.reftag = cpu_to_le32(io.reftag);
        c.rw.apptag = cpu_to_le16(io.apptag);
        c.rw.appmask = cpu_to_le16(io.appmask);

        return __nvme_submit_user_cmd(ns->queue, &c,
                        (void __user *)(uintptr_t)io.addr, length,
                        metadata, meta_len, io.slba, NULL, 0);
}

static int nvme_user_cmd(struct nvme_ctrl *ctrl, struct nvme_ns *ns,
                        struct nvme_passthru_cmd __user *ucmd)
{
        struct nvme_passthru_cmd cmd;
        struct nvme_command c;
        unsigned timeout = 0;
        int status;

        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;
        if (copy_from_user(&cmd, ucmd, sizeof(cmd)))
                return -EFAULT;

        memset(&c, 0, sizeof(c));
        c.common.opcode = cmd.opcode;
        c.common.flags = cmd.flags;
        c.common.nsid = cpu_to_le32(cmd.nsid);
        c.common.cdw2[0] = cpu_to_le32(cmd.cdw2);
        c.common.cdw2[1] = cpu_to_le32(cmd.cdw3);
        c.common.cdw10[0] = cpu_to_le32(cmd.cdw10);
        c.common.cdw10[1] = cpu_to_le32(cmd.cdw11);
        c.common.cdw10[2] = cpu_to_le32(cmd.cdw12);
        c.common.cdw10[3] = cpu_to_le32(cmd.cdw13);
        c.common.cdw10[4] = cpu_to_le32(cmd.cdw14);
        c.common.cdw10[5] = cpu_to_le32(cmd.cdw15);

        if (cmd.timeout_ms)
                timeout = msecs_to_jiffies(cmd.timeout_ms);

        status = nvme_submit_user_cmd(ns ? ns->queue : ctrl->admin_q, &c,
                        (void __user *)(uintptr_t)cmd.addr, cmd.data_len,
                        &cmd.result, timeout);
        if (status >= 0) {
                if (put_user(cmd.result, &ucmd->result))
                        return -EFAULT;
        }

        return status;
}

static int nvme_ioctl(struct block_device *bdev, fmode_t mode,
                unsigned int cmd, unsigned long arg)
{
        struct nvme_ns *ns = bdev->bd_disk->private_data;

        switch (cmd) {
        case NVME_IOCTL_ID:
                force_successful_syscall_return();
                return ns->ns_id;
        case NVME_IOCTL_ADMIN_CMD:
                return nvme_user_cmd(ns->ctrl, NULL, (void __user *)arg);
        case NVME_IOCTL_IO_CMD:
                return nvme_user_cmd(ns->ctrl, ns, (void __user *)arg);
        case NVME_IOCTL_SUBMIT_IO:
                return nvme_submit_io(ns, (void __user *)arg);
        case SG_GET_VERSION_NUM:
                return nvme_sg_get_version_num((void __user *)arg);
        case SG_IO:
                return nvme_sg_io(ns, (void __user *)arg);
        default:
                return -ENOTTY;
        }
}

#ifdef CONFIG_COMPAT
static int nvme_compat_ioctl(struct block_device *bdev, fmode_t mode,
                        unsigned int cmd, unsigned long arg)
{
        switch (cmd) {
        case SG_IO:
                return -ENOIOCTLCMD;
        }
        return nvme_ioctl(bdev, mode, cmd, arg);
}
#else
#define nvme_compat_ioctl       NULL
#endif

static int nvme_open(struct block_device *bdev, fmode_t mode)
{
        return nvme_get_ns_from_disk(bdev->bd_disk) ? 0 : -ENXIO;
}

static void nvme_release(struct gendisk *disk, fmode_t mode)
{
        nvme_put_ns(disk->private_data);
}

static int nvme_getgeo(struct block_device *bdev, struct hd_geometry *geo)
{
        /* some standard values */
        geo->heads = 1 << 6;
        geo->sectors = 1 << 5;
        geo->cylinders = get_capacity(bdev->bd_disk) >> 11;
        return 0;
}

#ifdef CONFIG_BLK_DEV_INTEGRITY
static void nvme_init_integrity(struct nvme_ns *ns)
{
        struct blk_integrity integrity;

        switch (ns->pi_type) {
        case NVME_NS_DPS_PI_TYPE3:
                integrity.profile = &t10_pi_type3_crc;
                break;
        case NVME_NS_DPS_PI_TYPE1:
        case NVME_NS_DPS_PI_TYPE2:
                integrity.profile = &t10_pi_type1_crc;
                break;
        default:
                integrity.profile = NULL;
                break;
        }
        integrity.tuple_size = ns->ms;
        blk_integrity_register(ns->disk, &integrity);
        blk_queue_max_integrity_segments(ns->queue, 1);
}
#else
static void nvme_init_integrity(struct nvme_ns *ns)
{
}
#endif /* CONFIG_BLK_DEV_INTEGRITY */

static void nvme_config_discard(struct nvme_ns *ns)
{
        u32 logical_block_size = queue_logical_block_size(ns->queue);
        ns->queue->limits.discard_zeroes_data = 0;
        ns->queue->limits.discard_alignment = logical_block_size;
        ns->queue->limits.discard_granularity = logical_block_size;
        blk_queue_max_discard_sectors(ns->queue, 0xffffffff);
        queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, ns->queue);
}

static int nvme_revalidate_disk(struct gendisk *disk)
{
        struct nvme_ns *ns = disk->private_data;
        struct nvme_id_ns *id;
        u8 lbaf, pi_type;
        u16 old_ms;
        unsigned short bs;

        if (nvme_identify_ns(ns->ctrl, ns->ns_id, &id)) {
                dev_warn(ns->ctrl->dev, "%s: Identify failure nvme%dn%d\n",
                                __func__, ns->ctrl->instance, ns->ns_id);
                return -ENODEV;
        }
        if (id->ncap == 0) {
                kfree(id);
                return -ENODEV;
        }

        if (nvme_nvm_ns_supported(ns, id) && ns->type != NVME_NS_LIGHTNVM) {
                if (nvme_nvm_register(ns->queue, disk->disk_name)) {
                        dev_warn(ns->ctrl->dev,
                                "%s: LightNVM init failure\n", __func__);
                        kfree(id);
                        return -ENODEV;
                }
                ns->type = NVME_NS_LIGHTNVM;
        }

        old_ms = ns->ms;
        lbaf = id->flbas & NVME_NS_FLBAS_LBA_MASK;
        ns->lba_shift = id->lbaf[lbaf].ds;
        ns->ms = le16_to_cpu(id->lbaf[lbaf].ms);
        ns->ext = ns->ms && (id->flbas & NVME_NS_FLBAS_META_EXT);

        /*
         * If identify namespace failed, use default 512 byte block size so
         * block layer can use before failing read/write for 0 capacity.
         */
        if (ns->lba_shift == 0)
                ns->lba_shift = 9;
        bs = 1 << ns->lba_shift;

        /* XXX: PI implementation requires metadata equal t10 pi tuple size */
        pi_type = ns->ms == sizeof(struct t10_pi_tuple) ?
                                        id->dps & NVME_NS_DPS_PI_MASK : 0;

        blk_mq_freeze_queue(disk->queue);
        if (blk_get_integrity(disk) && (ns->pi_type != pi_type ||
                                ns->ms != old_ms ||
                                bs != queue_logical_block_size(disk->queue) ||
                                (ns->ms && ns->ext)))
                blk_integrity_unregister(disk);

        ns->pi_type = pi_type;
        blk_queue_logical_block_size(ns->queue, bs);

        if (ns->ms && !ns->ext)
                nvme_init_integrity(ns);

        if (ns->ms && !(ns->ms == 8 && ns->pi_type) && !blk_get_integrity(disk))
                set_capacity(disk, 0);
        else
                set_capacity(disk, le64_to_cpup(&id->nsze) << (ns->lba_shift - 9));

        if (ns->ctrl->oncs & NVME_CTRL_ONCS_DSM)
                nvme_config_discard(ns);
        blk_mq_unfreeze_queue(disk->queue);

        kfree(id);
        return 0;
}

static char nvme_pr_type(enum pr_type type)
{
        switch (type) {
        case PR_WRITE_EXCLUSIVE:
                return 1;
        case PR_EXCLUSIVE_ACCESS:
                return 2;
        case PR_WRITE_EXCLUSIVE_REG_ONLY:
                return 3;
        case PR_EXCLUSIVE_ACCESS_REG_ONLY:
                return 4;
        case PR_WRITE_EXCLUSIVE_ALL_REGS:
                return 5;
        case PR_EXCLUSIVE_ACCESS_ALL_REGS:
                return 6;
        default:
                return 0;
        }
};

static int nvme_pr_command(struct block_device *bdev, u32 cdw10,
                                u64 key, u64 sa_key, u8 op)
{
        struct nvme_ns *ns = bdev->bd_disk->private_data;
        struct nvme_command c;
        u8 data[16] = { 0, };

        put_unaligned_le64(key, &data[0]);
        put_unaligned_le64(sa_key, &data[8]);

        memset(&c, 0, sizeof(c));
        c.common.opcode = op;
        c.common.nsid = cpu_to_le32(ns->ns_id);
        c.common.cdw10[0] = cpu_to_le32(cdw10);

        return nvme_submit_sync_cmd(ns->queue, &c, data, 16);
}

static int nvme_pr_register(struct block_device *bdev, u64 old,
                u64 new, unsigned flags)
{
        u32 cdw10;

        if (flags & ~PR_FL_IGNORE_KEY)
                return -EOPNOTSUPP;

        cdw10 = old ? 2 : 0;
        cdw10 |= (flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0;
        cdw10 |= (1 << 30) | (1 << 31); /* PTPL=1 */
        return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_register);
}

static int nvme_pr_reserve(struct block_device *bdev, u64 key,
                enum pr_type type, unsigned flags)
{
        u32 cdw10;

        if (flags & ~PR_FL_IGNORE_KEY)
                return -EOPNOTSUPP;

        cdw10 = nvme_pr_type(type) << 8;
        cdw10 |= ((flags & PR_FL_IGNORE_KEY) ? 1 << 3 : 0);
        return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_acquire);
}

static int nvme_pr_preempt(struct block_device *bdev, u64 old, u64 new,
                enum pr_type type, bool abort)
{
        u32 cdw10 = nvme_pr_type(type) << 8 | abort ? 2 : 1;
        return nvme_pr_command(bdev, cdw10, old, new, nvme_cmd_resv_acquire);
}

static int nvme_pr_clear(struct block_device *bdev, u64 key)
{
        u32 cdw10 = 1 | (key ? 1 << 3 : 0);
        return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_register);
}

static int nvme_pr_release(struct block_device *bdev, u64 key, enum pr_type type)
{
        u32 cdw10 = nvme_pr_type(type) << 8 | key ? 1 << 3 : 0;
        return nvme_pr_command(bdev, cdw10, key, 0, nvme_cmd_resv_release);
}

static const struct pr_ops nvme_pr_ops = {
        .pr_register    = nvme_pr_register,
        .pr_reserve     = nvme_pr_reserve,
        .pr_release     = nvme_pr_release,
        .pr_preempt     = nvme_pr_preempt,
        .pr_clear       = nvme_pr_clear,
};

static const struct block_device_operations nvme_fops = {
        .owner          = THIS_MODULE,
        .ioctl          = nvme_ioctl,
        .compat_ioctl   = nvme_compat_ioctl,
        .open           = nvme_open,
        .release        = nvme_release,
        .getgeo         = nvme_getgeo,
        .revalidate_disk= nvme_revalidate_disk,
        .pr_ops         = &nvme_pr_ops,
};

static int nvme_wait_ready(struct nvme_ctrl *ctrl, u64 cap, bool enabled)
{
        unsigned long timeout =
                ((NVME_CAP_TIMEOUT(cap) + 1) * HZ / 2) + jiffies;
        u32 csts, bit = enabled ? NVME_CSTS_RDY : 0;
        int ret;

        while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
                if ((csts & NVME_CSTS_RDY) == bit)
                        break;

                msleep(100);
                if (fatal_signal_pending(current))
                        return -EINTR;
                if (time_after(jiffies, timeout)) {
                        dev_err(ctrl->dev,
                                "Device not ready; aborting %s\n", enabled ?
                                                "initialisation" : "reset");
                        return -ENODEV;
                }
        }

        return ret;
}

/*
 * If the device has been passed off to us in an enabled state, just clear
 * the enabled bit.  The spec says we should set the 'shutdown notification
 * bits', but doing so may cause the device to complete commands to the
 * admin queue ... and we don't know what memory that might be pointing at!
 */
int nvme_disable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
{
        int ret;

        ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
        ctrl->ctrl_config &= ~NVME_CC_ENABLE;

        ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
        if (ret)
                return ret;
        return nvme_wait_ready(ctrl, cap, false);
}

int nvme_enable_ctrl(struct nvme_ctrl *ctrl, u64 cap)
{
        /*
         * Default to a 4K page size, with the intention to update this
         * path in the future to accomodate architectures with differing
         * kernel and IO page sizes.
         */
        unsigned dev_page_min = NVME_CAP_MPSMIN(cap) + 12, page_shift = 12;
        int ret;

        if (page_shift < dev_page_min) {
                dev_err(ctrl->dev,
                        "Minimum device page size %u too large for host (%u)\n",
                        1 << dev_page_min, 1 << page_shift);
                return -ENODEV;
        }

        ctrl->page_size = 1 << page_shift;

        ctrl->ctrl_config = NVME_CC_CSS_NVM;
        ctrl->ctrl_config |= (page_shift - 12) << NVME_CC_MPS_SHIFT;
        ctrl->ctrl_config |= NVME_CC_ARB_RR | NVME_CC_SHN_NONE;
        ctrl->ctrl_config |= NVME_CC_IOSQES | NVME_CC_IOCQES;
        ctrl->ctrl_config |= NVME_CC_ENABLE;

        ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
        if (ret)
                return ret;
        return nvme_wait_ready(ctrl, cap, true);
}

int nvme_shutdown_ctrl(struct nvme_ctrl *ctrl)
{
        unsigned long timeout = SHUTDOWN_TIMEOUT + jiffies;
        u32 csts;
        int ret;

        ctrl->ctrl_config &= ~NVME_CC_SHN_MASK;
        ctrl->ctrl_config |= NVME_CC_SHN_NORMAL;

        ret = ctrl->ops->reg_write32(ctrl, NVME_REG_CC, ctrl->ctrl_config);
        if (ret)
                return ret;

        while ((ret = ctrl->ops->reg_read32(ctrl, NVME_REG_CSTS, &csts)) == 0) {
                if ((csts & NVME_CSTS_SHST_MASK) == NVME_CSTS_SHST_CMPLT)
                        break;

                msleep(100);
                if (fatal_signal_pending(current))
                        return -EINTR;
                if (time_after(jiffies, timeout)) {
                        dev_err(ctrl->dev,
                                "Device shutdown incomplete; abort shutdown\n");
                        return -ENODEV;
                }
        }

        return ret;
}

/*
 * Initialize the cached copies of the Identify data and various controller
 * register in our nvme_ctrl structure.  This should be called as soon as
 * the admin queue is fully up and running.
 */
int nvme_init_identify(struct nvme_ctrl *ctrl)
{
        struct nvme_id_ctrl *id;
        u64 cap;
        int ret, page_shift;

        ret = ctrl->ops->reg_read32(ctrl, NVME_REG_VS, &ctrl->vs);
        if (ret) {
                dev_err(ctrl->dev, "Reading VS failed (%d)\n", ret);
                return ret;
        }

        ret = ctrl->ops->reg_read64(ctrl, NVME_REG_CAP, &cap);
        if (ret) {
                dev_err(ctrl->dev, "Reading CAP failed (%d)\n", ret);
                return ret;
        }
        page_shift = NVME_CAP_MPSMIN(cap) + 12;

        if (ctrl->vs >= NVME_VS(1, 1))
                ctrl->subsystem = NVME_CAP_NSSRC(cap);

        ret = nvme_identify_ctrl(ctrl, &id);
        if (ret) {
                dev_err(ctrl->dev, "Identify Controller failed (%d)\n", ret);
                return -EIO;
        }

        ctrl->oncs = le16_to_cpup(&id->oncs);
        atomic_set(&ctrl->abort_limit, id->acl + 1);
        ctrl->vwc = id->vwc;
        memcpy(ctrl->serial, id->sn, sizeof(id->sn));
        memcpy(ctrl->model, id->mn, sizeof(id->mn));
        memcpy(ctrl->firmware_rev, id->fr, sizeof(id->fr));
        if (id->mdts)
                ctrl->max_hw_sectors = 1 << (id->mdts + page_shift - 9);
        else
                ctrl->max_hw_sectors = UINT_MAX;

        if ((ctrl->quirks & NVME_QUIRK_STRIPE_SIZE) && id->vs[3]) {
                unsigned int max_hw_sectors;

                ctrl->stripe_size = 1 << (id->vs[3] + page_shift);
                max_hw_sectors = ctrl->stripe_size >> (page_shift - 9);
                if (ctrl->max_hw_sectors) {
                        ctrl->max_hw_sectors = min(max_hw_sectors,
                                                        ctrl->max_hw_sectors);
                } else {
                        ctrl->max_hw_sectors = max_hw_sectors;
                }
        }

        kfree(id);
        return 0;
}

static int nvme_dev_open(struct inode *inode, struct file *file)
{
        struct nvme_ctrl *ctrl;
        int instance = iminor(inode);
        int ret = -ENODEV;

        spin_lock(&dev_list_lock);
        list_for_each_entry(ctrl, &nvme_ctrl_list, node) {
                if (ctrl->instance != instance)
                        continue;

                if (!ctrl->admin_q) {
                        ret = -EWOULDBLOCK;
                        break;
                }
                if (!kref_get_unless_zero(&ctrl->kref))
                        break;
                file->private_data = ctrl;
                ret = 0;
                break;
        }
        spin_unlock(&dev_list_lock);

        return ret;
}

static int nvme_dev_release(struct inode *inode, struct file *file)
{
        nvme_put_ctrl(file->private_data);
        return 0;
}

static long nvme_dev_ioctl(struct file *file, unsigned int cmd,
                unsigned long arg)
{
        struct nvme_ctrl *ctrl = file->private_data;
        void __user *argp = (void __user *)arg;
        struct nvme_ns *ns;

        switch (cmd) {
        case NVME_IOCTL_ADMIN_CMD:
                return nvme_user_cmd(ctrl, NULL, argp);
        case NVME_IOCTL_IO_CMD:
                if (list_empty(&ctrl->namespaces))
                        return -ENOTTY;
                ns = list_first_entry(&ctrl->namespaces, struct nvme_ns, list);
                return nvme_user_cmd(ctrl, ns, argp);
        case NVME_IOCTL_RESET:
                dev_warn(ctrl->dev, "resetting controller\n");
                return ctrl->ops->reset_ctrl(ctrl);
        case NVME_IOCTL_SUBSYS_RESET:
                return nvme_reset_subsystem(ctrl);
        default:
                return -ENOTTY;
        }
}

static const struct file_operations nvme_dev_fops = {
        .owner          = THIS_MODULE,
        .open           = nvme_dev_open,
        .release        = nvme_dev_release,
        .unlocked_ioctl = nvme_dev_ioctl,
        .compat_ioctl   = nvme_dev_ioctl,
};

static ssize_t nvme_sysfs_reset(struct device *dev,
                                struct device_attribute *attr, const char *buf,
                                size_t count)
{
        struct nvme_ctrl *ctrl = dev_get_drvdata(dev);
        int ret;

        ret = ctrl->ops->reset_ctrl(ctrl);
        if (ret < 0)
                return ret;
        return count;
}
static DEVICE_ATTR(reset_controller, S_IWUSR, NULL, nvme_sysfs_reset);

static int ns_cmp(void *priv, struct list_head *a, struct list_head *b)
{
        struct nvme_ns *nsa = container_of(a, struct nvme_ns, list);
        struct nvme_ns *nsb = container_of(b, struct nvme_ns, list);

        return nsa->ns_id - nsb->ns_id;
}

static struct nvme_ns *nvme_find_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
        struct nvme_ns *ns;

        list_for_each_entry(ns, &ctrl->namespaces, list) {
                if (ns->ns_id == nsid)
                        return ns;
                if (ns->ns_id > nsid)
                        break;
        }
        return NULL;
}

static void nvme_alloc_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
        struct nvme_ns *ns;
        struct gendisk *disk;
        int node = dev_to_node(ctrl->dev);

        ns = kzalloc_node(sizeof(*ns), GFP_KERNEL, node);
        if (!ns)
                return;

        ns->queue = blk_mq_init_queue(ctrl->tagset);
        if (IS_ERR(ns->queue))
                goto out_free_ns;
        queue_flag_set_unlocked(QUEUE_FLAG_NOMERGES, ns->queue);
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, ns->queue);
        ns->queue->queuedata = ns;
        ns->ctrl = ctrl;

        disk = alloc_disk_node(0, node);
        if (!disk)
                goto out_free_queue;

        kref_init(&ns->kref);
        ns->ns_id = nsid;
        ns->disk = disk;
        ns->lba_shift = 9; /* set to a default value for 512 until disk is validated */
        list_add_tail(&ns->list, &ctrl->namespaces);

        blk_queue_logical_block_size(ns->queue, 1 << ns->lba_shift);
        if (ctrl->max_hw_sectors) {
                blk_queue_max_hw_sectors(ns->queue, ctrl->max_hw_sectors);
                blk_queue_max_segments(ns->queue,
                        (ctrl->max_hw_sectors / (ctrl->page_size >> 9)) + 1);
        }
        if (ctrl->stripe_size)
                blk_queue_chunk_sectors(ns->queue, ctrl->stripe_size >> 9);
        if (ctrl->vwc & NVME_CTRL_VWC_PRESENT)
                blk_queue_flush(ns->queue, REQ_FLUSH | REQ_FUA);
        blk_queue_virt_boundary(ns->queue, ctrl->page_size - 1);

        disk->major = nvme_major;
        disk->first_minor = 0;
        disk->fops = &nvme_fops;
        disk->private_data = ns;
        disk->queue = ns->queue;
        disk->driverfs_dev = ctrl->device;
        disk->flags = GENHD_FL_EXT_DEVT;
        sprintf(disk->disk_name, "nvme%dn%d", ctrl->instance, nsid);

        /*
         * Initialize capacity to 0 until we establish the namespace format and
         * setup integrity extentions if necessary. The revalidate_disk after
         * add_disk allows the driver to register with integrity if the format
         * requires it.
         */
        set_capacity(disk, 0);
        if (nvme_revalidate_disk(ns->disk))
                goto out_free_disk;

        kref_get(&ctrl->kref);
        if (ns->type != NVME_NS_LIGHTNVM) {
                add_disk(ns->disk);
                if (ns->ms) {
                        struct block_device *bd = bdget_disk(ns->disk, 0);
                        if (!bd)
                                return;
                        if (blkdev_get(bd, FMODE_READ, NULL)) {
                                bdput(bd);
                                return;
                        }
                        blkdev_reread_part(bd);
                        blkdev_put(bd, FMODE_READ);
                }
        }

        return;
 out_free_disk:
        kfree(disk);
        list_del(&ns->list);
 out_free_queue:
        blk_cleanup_queue(ns->queue);
 out_free_ns:
        kfree(ns);
}

static void nvme_ns_remove(struct nvme_ns *ns)
{
        bool kill = nvme_io_incapable(ns->ctrl) &&
                        !blk_queue_dying(ns->queue);

        if (kill)
                blk_set_queue_dying(ns->queue);
        if (ns->disk->flags & GENHD_FL_UP) {
                if (blk_get_integrity(ns->disk))
                        blk_integrity_unregister(ns->disk);
                del_gendisk(ns->disk);
        }
        if (kill || !blk_queue_dying(ns->queue)) {
                blk_mq_abort_requeue_list(ns->queue);
                blk_cleanup_queue(ns->queue);
        }
        list_del_init(&ns->list);
        nvme_put_ns(ns);
}

static void nvme_validate_ns(struct nvme_ctrl *ctrl, unsigned nsid)
{
        struct nvme_ns *ns;

        ns = nvme_find_ns(ctrl, nsid);
        if (ns) {
                if (revalidate_disk(ns->disk))
                        nvme_ns_remove(ns);
        } else
                nvme_alloc_ns(ctrl, nsid);
}

static int nvme_scan_ns_list(struct nvme_ctrl *ctrl, unsigned nn)
{
        struct nvme_ns *ns;
        __le32 *ns_list;
        unsigned i, j, nsid, prev = 0, num_lists = DIV_ROUND_UP(nn, 1024);
        int ret = 0;

        ns_list = kzalloc(0x1000, GFP_KERNEL);
        if (!ns_list)
                return -ENOMEM;

        for (i = 0; i < num_lists; i++) {
                ret = nvme_identify_ns_list(ctrl, prev, ns_list);
                if (ret)
                        goto out;

                for (j = 0; j < min(nn, 1024U); j++) {
                        nsid = le32_to_cpu(ns_list[j]);
                        if (!nsid)
                                goto out;

                        nvme_validate_ns(ctrl, nsid);

                        while (++prev < nsid) {
                                ns = nvme_find_ns(ctrl, prev);
                                if (ns)
                                        nvme_ns_remove(ns);
                        }
                }
                nn -= j;
        }
 out:
        kfree(ns_list);
        return ret;
}

static void __nvme_scan_namespaces(struct nvme_ctrl *ctrl, unsigned nn)
{
        struct nvme_ns *ns, *next;
        unsigned i;

        for (i = 1; i <= nn; i++)
                nvme_validate_ns(ctrl, i);

        list_for_each_entry_safe(ns, next, &ctrl->namespaces, list) {
                if (ns->ns_id > nn)
                        nvme_ns_remove(ns);
        }
}

void nvme_scan_namespaces(struct nvme_ctrl *ctrl)
{
        struct nvme_id_ctrl *id;
        unsigned nn;

        if (nvme_identify_ctrl(ctrl, &id))
                return;

        nn = le32_to_cpu(id->nn);
        if (ctrl->vs >= NVME_VS(1, 1) &&
            !(ctrl->quirks & NVME_QUIRK_IDENTIFY_CNS)) {
                if (!nvme_scan_ns_list(ctrl, nn))
                        goto done;
        }
        __nvme_scan_namespaces(ctrl, le32_to_cpup(&id->nn));
 done:
        list_sort(NULL, &ctrl->namespaces, ns_cmp);
        kfree(id);
}

void nvme_remove_namespaces(struct nvme_ctrl *ctrl)
{
        struct nvme_ns *ns, *next;

        list_for_each_entry_safe(ns, next, &ctrl->namespaces, list)
                nvme_ns_remove(ns);
}

static DEFINE_IDA(nvme_instance_ida);

static int nvme_set_instance(struct nvme_ctrl *ctrl)
{
        int instance, error;

        do {
                if (!ida_pre_get(&nvme_instance_ida, GFP_KERNEL))
                        return -ENODEV;

                spin_lock(&dev_list_lock);
                error = ida_get_new(&nvme_instance_ida, &instance);
                spin_unlock(&dev_list_lock);
        } while (error == -EAGAIN);

        if (error)
                return -ENODEV;

        ctrl->instance = instance;
        return 0;
}

static void nvme_release_instance(struct nvme_ctrl *ctrl)
{
        spin_lock(&dev_list_lock);
        ida_remove(&nvme_instance_ida, ctrl->instance);
        spin_unlock(&dev_list_lock);
}

static void nvme_free_ctrl(struct kref *kref)
{
        struct nvme_ctrl *ctrl = container_of(kref, struct nvme_ctrl, kref);

        spin_lock(&dev_list_lock);
        list_del(&ctrl->node);
        spin_unlock(&dev_list_lock);

        put_device(ctrl->device);
        nvme_release_instance(ctrl);
        device_destroy(nvme_class, MKDEV(nvme_char_major, ctrl->instance));

        ctrl->ops->free_ctrl(ctrl);
}

void nvme_put_ctrl(struct nvme_ctrl *ctrl)
{
        kref_put(&ctrl->kref, nvme_free_ctrl);
}

/*
 * Initialize a NVMe controller structures.  This needs to be called during
 * earliest initialization so that we have the initialized structured around
 * during probing.
 */
int nvme_init_ctrl(struct nvme_ctrl *ctrl, struct device *dev,
                const struct nvme_ctrl_ops *ops, unsigned long quirks)
{
        int ret;

        INIT_LIST_HEAD(&ctrl->namespaces);
        kref_init(&ctrl->kref);
        ctrl->dev = dev;
        ctrl->ops = ops;
        ctrl->quirks = quirks;

        ret = nvme_set_instance(ctrl);
        if (ret)
                goto out;

        ctrl->device = device_create(nvme_class, ctrl->dev,
                                MKDEV(nvme_char_major, ctrl->instance),
                                dev, "nvme%d", ctrl->instance);
        if (IS_ERR(ctrl->device)) {
                ret = PTR_ERR(ctrl->device);
                goto out_release_instance;
        }
        get_device(ctrl->device);
        dev_set_drvdata(ctrl->device, ctrl);

        ret = device_create_file(ctrl->device, &dev_attr_reset_controller);
        if (ret)
                goto out_put_device;

        spin_lock(&dev_list_lock);
        list_add_tail(&ctrl->node, &nvme_ctrl_list);
        spin_unlock(&dev_list_lock);

        return 0;

out_put_device:
        put_device(ctrl->device);
        device_destroy(nvme_class, MKDEV(nvme_char_major, ctrl->instance));
out_release_instance:
        nvme_release_instance(ctrl);
out:
        return ret;
}

int __init nvme_core_init(void)
{
        int result;

        result = register_blkdev(nvme_major, "nvme");
        if (result < 0)
                return result;
        else if (result > 0)
                nvme_major = result;

        result = __register_chrdev(nvme_char_major, 0, NVME_MINORS, "nvme",
                                                        &nvme_dev_fops);
        if (result < 0)
                goto unregister_blkdev;
        else if (result > 0)
                nvme_char_major = result;

        nvme_class = class_create(THIS_MODULE, "nvme");
        if (IS_ERR(nvme_class)) {
                result = PTR_ERR(nvme_class);
                goto unregister_chrdev;
        }

        return 0;

 unregister_chrdev:
        __unregister_chrdev(nvme_char_major, 0, NVME_MINORS, "nvme");
 unregister_blkdev:
        unregister_blkdev(nvme_major, "nvme");
        return result;
}

void nvme_core_exit(void)
{
        unregister_blkdev(nvme_major, "nvme");
        class_destroy(nvme_class);
        __unregister_chrdev(nvme_char_major, 0, NVME_MINORS, "nvme");
}