virtio_ring: fix num_free handling in error case

[cris-mirror.git] / drivers / scsi / sd_zbc.c

/*
 * SCSI Zoned Block commands
 *
 * Copyright (C) 2014-2015 SUSE Linux GmbH
 * Written by: Hannes Reinecke <hare@suse.de>
 * Modified by: Damien Le Moal <damien.lemoal@hgst.com>
 * Modified by: Shaun Tancheff <shaun.tancheff@seagate.com>
 *
 * 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.
 *
 * 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; see the file COPYING.  If not, write to
 * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
 * USA.
 *
 */

#include <linux/blkdev.h>

#include <asm/unaligned.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>

#include "sd.h"

/**
 * sd_zbc_parse_report - Convert a zone descriptor to a struct blk_zone,
 * @sdkp: The disk the report originated from
 * @buf: Address of the report zone descriptor
 * @zone: the destination zone structure
 *
 * All LBA sized values are converted to 512B sectors unit.
 */
static void sd_zbc_parse_report(struct scsi_disk *sdkp, u8 *buf,
                                struct blk_zone *zone)
{
        struct scsi_device *sdp = sdkp->device;

        memset(zone, 0, sizeof(struct blk_zone));

        zone->type = buf[0] & 0x0f;
        zone->cond = (buf[1] >> 4) & 0xf;
        if (buf[1] & 0x01)
                zone->reset = 1;
        if (buf[1] & 0x02)
                zone->non_seq = 1;

        zone->len = logical_to_sectors(sdp, get_unaligned_be64(&buf[8]));
        zone->start = logical_to_sectors(sdp, get_unaligned_be64(&buf[16]));
        zone->wp = logical_to_sectors(sdp, get_unaligned_be64(&buf[24]));
        if (zone->type != ZBC_ZONE_TYPE_CONV &&
            zone->cond == ZBC_ZONE_COND_FULL)
                zone->wp = zone->start + zone->len;
}

/**
 * sd_zbc_report_zones - Issue a REPORT ZONES scsi command.
 * @sdkp: The target disk
 * @buf: Buffer to use for the reply
 * @buflen: the buffer size
 * @lba: Start LBA of the report
 *
 * For internal use during device validation.
 */
static int sd_zbc_report_zones(struct scsi_disk *sdkp, unsigned char *buf,
                               unsigned int buflen, sector_t lba)
{
        struct scsi_device *sdp = sdkp->device;
        const int timeout = sdp->request_queue->rq_timeout;
        struct scsi_sense_hdr sshdr;
        unsigned char cmd[16];
        unsigned int rep_len;
        int result;

        memset(cmd, 0, 16);
        cmd[0] = ZBC_IN;
        cmd[1] = ZI_REPORT_ZONES;
        put_unaligned_be64(lba, &cmd[2]);
        put_unaligned_be32(buflen, &cmd[10]);
        memset(buf, 0, buflen);

        result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
                                  buf, buflen, &sshdr,
                                  timeout, SD_MAX_RETRIES, NULL);
        if (result) {
                sd_printk(KERN_ERR, sdkp,
                          "REPORT ZONES lba %llu failed with %d/%d\n",
                          (unsigned long long)lba,
                          host_byte(result), driver_byte(result));
                return -EIO;
        }

        rep_len = get_unaligned_be32(&buf[0]);
        if (rep_len < 64) {
                sd_printk(KERN_ERR, sdkp,
                          "REPORT ZONES report invalid length %u\n",
                          rep_len);
                return -EIO;
        }

        return 0;
}

/**
 * sd_zbc_setup_report_cmnd - Prepare a REPORT ZONES scsi command
 * @cmd: The command to setup
 *
 * Call in sd_init_command() for a REQ_OP_ZONE_REPORT request.
 */
int sd_zbc_setup_report_cmnd(struct scsi_cmnd *cmd)
{
        struct request *rq = cmd->request;
        struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
        sector_t lba, sector = blk_rq_pos(rq);
        unsigned int nr_bytes = blk_rq_bytes(rq);
        int ret;

        WARN_ON(nr_bytes == 0);

        if (!sd_is_zoned(sdkp))
                /* Not a zoned device */
                return BLKPREP_KILL;

        ret = scsi_init_io(cmd);
        if (ret != BLKPREP_OK)
                return ret;

        cmd->cmd_len = 16;
        memset(cmd->cmnd, 0, cmd->cmd_len);
        cmd->cmnd[0] = ZBC_IN;
        cmd->cmnd[1] = ZI_REPORT_ZONES;
        lba = sectors_to_logical(sdkp->device, sector);
        put_unaligned_be64(lba, &cmd->cmnd[2]);
        put_unaligned_be32(nr_bytes, &cmd->cmnd[10]);
        /* Do partial report for speeding things up */
        cmd->cmnd[14] = ZBC_REPORT_ZONE_PARTIAL;

        cmd->sc_data_direction = DMA_FROM_DEVICE;
        cmd->sdb.length = nr_bytes;
        cmd->transfersize = sdkp->device->sector_size;
        cmd->allowed = 0;

        /*
         * Report may return less bytes than requested. Make sure
         * to report completion on the entire initial request.
         */
        rq->__data_len = nr_bytes;

        return BLKPREP_OK;
}

/**
 * sd_zbc_report_zones_complete - Process a REPORT ZONES scsi command reply.
 * @scmd: The completed report zones command
 * @good_bytes: reply size in bytes
 *
 * Convert all reported zone descriptors to struct blk_zone. The conversion
 * is done in-place, directly in the request specified sg buffer.
 */
static void sd_zbc_report_zones_complete(struct scsi_cmnd *scmd,
                                         unsigned int good_bytes)
{
        struct request *rq = scmd->request;
        struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
        struct sg_mapping_iter miter;
        struct blk_zone_report_hdr hdr;
        struct blk_zone zone;
        unsigned int offset, bytes = 0;
        unsigned long flags;
        u8 *buf;

        if (good_bytes < 64)
                return;

        memset(&hdr, 0, sizeof(struct blk_zone_report_hdr));

        sg_miter_start(&miter, scsi_sglist(scmd), scsi_sg_count(scmd),
                       SG_MITER_TO_SG | SG_MITER_ATOMIC);

        local_irq_save(flags);
        while (sg_miter_next(&miter) && bytes < good_bytes) {

                buf = miter.addr;
                offset = 0;

                if (bytes == 0) {
                        /* Set the report header */
                        hdr.nr_zones = min_t(unsigned int,
                                         (good_bytes - 64) / 64,
                                         get_unaligned_be32(&buf[0]) / 64);
                        memcpy(buf, &hdr, sizeof(struct blk_zone_report_hdr));
                        offset += 64;
                        bytes += 64;
                }

                /* Parse zone descriptors */
                while (offset < miter.length && hdr.nr_zones) {
                        WARN_ON(offset > miter.length);
                        buf = miter.addr + offset;
                        sd_zbc_parse_report(sdkp, buf, &zone);
                        memcpy(buf, &zone, sizeof(struct blk_zone));
                        offset += 64;
                        bytes += 64;
                        hdr.nr_zones--;
                }

                if (!hdr.nr_zones)
                        break;

        }
        sg_miter_stop(&miter);
        local_irq_restore(flags);
}

/**
 * sd_zbc_zone_sectors - Get the device zone size in number of 512B sectors.
 * @sdkp: The target disk
 */
static inline sector_t sd_zbc_zone_sectors(struct scsi_disk *sdkp)
{
        return logical_to_sectors(sdkp->device, sdkp->zone_blocks);
}

/**
 * sd_zbc_setup_reset_cmnd - Prepare a RESET WRITE POINTER scsi command.
 * @cmd: the command to setup
 *
 * Called from sd_init_command() for a REQ_OP_ZONE_RESET request.
 */
int sd_zbc_setup_reset_cmnd(struct scsi_cmnd *cmd)
{
        struct request *rq = cmd->request;
        struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
        sector_t sector = blk_rq_pos(rq);
        sector_t block = sectors_to_logical(sdkp->device, sector);

        if (!sd_is_zoned(sdkp))
                /* Not a zoned device */
                return BLKPREP_KILL;

        if (sdkp->device->changed)
                return BLKPREP_KILL;

        if (sector & (sd_zbc_zone_sectors(sdkp) - 1))
                /* Unaligned request */
                return BLKPREP_KILL;

        cmd->cmd_len = 16;
        memset(cmd->cmnd, 0, cmd->cmd_len);
        cmd->cmnd[0] = ZBC_OUT;
        cmd->cmnd[1] = ZO_RESET_WRITE_POINTER;
        put_unaligned_be64(block, &cmd->cmnd[2]);

        rq->timeout = SD_TIMEOUT;
        cmd->sc_data_direction = DMA_NONE;
        cmd->transfersize = 0;
        cmd->allowed = 0;

        return BLKPREP_OK;
}

/**
 * sd_zbc_complete - ZBC command post processing.
 * @cmd: Completed command
 * @good_bytes: Command reply bytes
 * @sshdr: command sense header
 *
 * Called from sd_done(). Process report zones reply and handle reset zone
 * and write commands errors.
 */
void sd_zbc_complete(struct scsi_cmnd *cmd, unsigned int good_bytes,
                     struct scsi_sense_hdr *sshdr)
{
        int result = cmd->result;
        struct request *rq = cmd->request;

        switch (req_op(rq)) {
        case REQ_OP_ZONE_RESET:

                if (result &&
                    sshdr->sense_key == ILLEGAL_REQUEST &&
                    sshdr->asc == 0x24)
                        /*
                         * INVALID FIELD IN CDB error: reset of a conventional
                         * zone was attempted. Nothing to worry about, so be
                         * quiet about the error.
                         */
                        rq->rq_flags |= RQF_QUIET;
                break;

        case REQ_OP_WRITE:
        case REQ_OP_WRITE_ZEROES:
        case REQ_OP_WRITE_SAME:

                if (result &&
                    sshdr->sense_key == ILLEGAL_REQUEST &&
                    sshdr->asc == 0x21)
                        /*
                         * INVALID ADDRESS FOR WRITE error: It is unlikely that
                         * retrying write requests failed with any kind of
                         * alignement error will result in success. So don't.
                         */
                        cmd->allowed = 0;
                break;

        case REQ_OP_ZONE_REPORT:

                if (!result)
                        sd_zbc_report_zones_complete(cmd, good_bytes);
                break;

        }
}

/**
 * sd_zbc_read_zoned_characteristics - Read zoned block device characteristics
 * @sdkp: Target disk
 * @buf: Buffer where to store the VPD page data
 *
 * Read VPD page B6.
 */
static int sd_zbc_read_zoned_characteristics(struct scsi_disk *sdkp,
                                             unsigned char *buf)
{

        if (scsi_get_vpd_page(sdkp->device, 0xb6, buf, 64)) {
                sd_printk(KERN_NOTICE, sdkp,
                          "Unconstrained-read check failed\n");
                return -ENODEV;
        }

        if (sdkp->device->type != TYPE_ZBC) {
                /* Host-aware */
                sdkp->urswrz = 1;
                sdkp->zones_optimal_open = get_unaligned_be32(&buf[8]);
                sdkp->zones_optimal_nonseq = get_unaligned_be32(&buf[12]);
                sdkp->zones_max_open = 0;
        } else {
                /* Host-managed */
                sdkp->urswrz = buf[4] & 1;
                sdkp->zones_optimal_open = 0;
                sdkp->zones_optimal_nonseq = 0;
                sdkp->zones_max_open = get_unaligned_be32(&buf[16]);
        }

        return 0;
}

/**
 * sd_zbc_check_capacity - Check reported capacity.
 * @sdkp: Target disk
 * @buf: Buffer to use for commands
 *
 * ZBC drive may report only the capacity of the first conventional zones at
 * LBA 0. This is indicated by the RC_BASIS field of the read capacity reply.
 * Check this here. If the disk reported only its conventional zones capacity,
 * get the total capacity by doing a report zones.
 */
static int sd_zbc_check_capacity(struct scsi_disk *sdkp, unsigned char *buf)
{
        sector_t lba;
        int ret;

        if (sdkp->rc_basis != 0)
                return 0;

        /* Do a report zone to get the maximum LBA to check capacity */
        ret = sd_zbc_report_zones(sdkp, buf, SD_BUF_SIZE, 0);
        if (ret)
                return ret;

        /* The max_lba field is the capacity of this device */
        lba = get_unaligned_be64(&buf[8]);
        if (lba + 1 == sdkp->capacity)
                return 0;

        if (sdkp->first_scan)
                sd_printk(KERN_WARNING, sdkp,
                          "Changing capacity from %llu to max LBA+1 %llu\n",
                          (unsigned long long)sdkp->capacity,
                          (unsigned long long)lba + 1);
        sdkp->capacity = lba + 1;

        return 0;
}

#define SD_ZBC_BUF_SIZE 131072U

/**
 * sd_zbc_check_zone_size - Check the device zone sizes
 * @sdkp: Target disk
 *
 * Check that all zones of the device are equal. The last zone can however
 * be smaller. The zone size must also be a power of two number of LBAs.
 */
static int sd_zbc_check_zone_size(struct scsi_disk *sdkp)
{
        u64 zone_blocks;
        sector_t block = 0;
        unsigned char *buf;
        unsigned char *rec;
        unsigned int buf_len;
        unsigned int list_length;
        int ret;
        u8 same;

        sdkp->zone_blocks = 0;

        /* Get a buffer */
        buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        /* Do a report zone to get the same field */
        ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, 0);
        if (ret) {
                zone_blocks = 0;
                goto out;
        }

        same = buf[4] & 0x0f;
        if (same > 0) {
                rec = &buf[64];
                zone_blocks = get_unaligned_be64(&rec[8]);
                goto out;
        }

        /*
         * Check the size of all zones: all zones must be of
         * equal size, except the last zone which can be smaller
         * than other zones.
         */
        do {

                /* Parse REPORT ZONES header */
                list_length = get_unaligned_be32(&buf[0]) + 64;
                rec = buf + 64;
                buf_len = min(list_length, SD_ZBC_BUF_SIZE);

                /* Parse zone descriptors */
                while (rec < buf + buf_len) {
                        zone_blocks = get_unaligned_be64(&rec[8]);
                        if (sdkp->zone_blocks == 0) {
                                sdkp->zone_blocks = zone_blocks;
                        } else if (zone_blocks != sdkp->zone_blocks &&
                                   (block + zone_blocks < sdkp->capacity
                                    || zone_blocks > sdkp->zone_blocks)) {
                                zone_blocks = 0;
                                goto out;
                        }
                        block += zone_blocks;
                        rec += 64;
                }

                if (block < sdkp->capacity) {
                        ret = sd_zbc_report_zones(sdkp, buf,
                                                  SD_ZBC_BUF_SIZE, block);
                        if (ret)
                                return ret;
                }

        } while (block < sdkp->capacity);

        zone_blocks = sdkp->zone_blocks;

out:
        kfree(buf);

        if (!zone_blocks) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Devices with non constant zone "
                                  "size are not supported\n");
                return -ENODEV;
        }

        if (!is_power_of_2(zone_blocks)) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Devices with non power of 2 zone "
                                  "size are not supported\n");
                return -ENODEV;
        }

        if (logical_to_sectors(sdkp->device, zone_blocks) > UINT_MAX) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                                  "Zone size too large\n");
                return -ENODEV;
        }

        sdkp->zone_blocks = zone_blocks;
        sdkp->zone_shift = ilog2(zone_blocks);

        return 0;
}

/**
 * sd_zbc_alloc_zone_bitmap - Allocate a zone bitmap (one bit per zone).
 * @sdkp: The disk of the bitmap
 */
static inline unsigned long *sd_zbc_alloc_zone_bitmap(struct scsi_disk *sdkp)
{
        struct request_queue *q = sdkp->disk->queue;

        return kzalloc_node(BITS_TO_LONGS(sdkp->nr_zones)
                            * sizeof(unsigned long),
                            GFP_KERNEL, q->node);
}

/**
 * sd_zbc_get_seq_zones - Parse report zones reply to identify sequential zones
 * @sdkp: disk used
 * @buf: report reply buffer
 * @seq_zone_bitamp: bitmap of sequential zones to set
 *
 * Parse reported zone descriptors in @buf to identify sequential zones and
 * set the reported zone bit in @seq_zones_bitmap accordingly.
 * Since read-only and offline zones cannot be written, do not
 * mark them as sequential in the bitmap.
 * Return the LBA after the last zone reported.
 */
static sector_t sd_zbc_get_seq_zones(struct scsi_disk *sdkp, unsigned char *buf,
                                     unsigned int buflen,
                                     unsigned long *seq_zones_bitmap)
{
        sector_t lba, next_lba = sdkp->capacity;
        unsigned int buf_len, list_length;
        unsigned char *rec;
        u8 type, cond;

        list_length = get_unaligned_be32(&buf[0]) + 64;
        buf_len = min(list_length, buflen);
        rec = buf + 64;

        while (rec < buf + buf_len) {
                type = rec[0] & 0x0f;
                cond = (rec[1] >> 4) & 0xf;
                lba = get_unaligned_be64(&rec[16]);
                if (type != ZBC_ZONE_TYPE_CONV &&
                    cond != ZBC_ZONE_COND_READONLY &&
                    cond != ZBC_ZONE_COND_OFFLINE)
                        set_bit(lba >> sdkp->zone_shift, seq_zones_bitmap);
                next_lba = lba + get_unaligned_be64(&rec[8]);
                rec += 64;
        }

        return next_lba;
}

/**
 * sd_zbc_setup_seq_zones_bitmap - Initialize the disk seq zone bitmap.
 * @sdkp: target disk
 *
 * Allocate a zone bitmap and initialize it by identifying sequential zones.
 */
static int sd_zbc_setup_seq_zones_bitmap(struct scsi_disk *sdkp)
{
        struct request_queue *q = sdkp->disk->queue;
        unsigned long *seq_zones_bitmap;
        sector_t lba = 0;
        unsigned char *buf;
        int ret = -ENOMEM;

        seq_zones_bitmap = sd_zbc_alloc_zone_bitmap(sdkp);
        if (!seq_zones_bitmap)
                return -ENOMEM;

        buf = kmalloc(SD_ZBC_BUF_SIZE, GFP_KERNEL);
        if (!buf)
                goto out;

        while (lba < sdkp->capacity) {
                ret = sd_zbc_report_zones(sdkp, buf, SD_ZBC_BUF_SIZE, lba);
                if (ret)
                        goto out;
                lba = sd_zbc_get_seq_zones(sdkp, buf, SD_ZBC_BUF_SIZE,
                                           seq_zones_bitmap);
        }

        if (lba != sdkp->capacity) {
                /* Something went wrong */
                ret = -EIO;
        }

out:
        kfree(buf);
        if (ret) {
                kfree(seq_zones_bitmap);
                return ret;
        }

        q->seq_zones_bitmap = seq_zones_bitmap;

        return 0;
}

static void sd_zbc_cleanup(struct scsi_disk *sdkp)
{
        struct request_queue *q = sdkp->disk->queue;

        kfree(q->seq_zones_bitmap);
        q->seq_zones_bitmap = NULL;

        kfree(q->seq_zones_wlock);
        q->seq_zones_wlock = NULL;

        q->nr_zones = 0;
}

static int sd_zbc_setup(struct scsi_disk *sdkp)
{
        struct request_queue *q = sdkp->disk->queue;
        int ret;

        /* READ16/WRITE16 is mandatory for ZBC disks */
        sdkp->device->use_16_for_rw = 1;
        sdkp->device->use_10_for_rw = 0;

        /* chunk_sectors indicates the zone size */
        blk_queue_chunk_sectors(sdkp->disk->queue,
                        logical_to_sectors(sdkp->device, sdkp->zone_blocks));
        sdkp->nr_zones =
                round_up(sdkp->capacity, sdkp->zone_blocks) >> sdkp->zone_shift;

        /*
         * Initialize the device request queue information if the number
         * of zones changed.
         */
        if (sdkp->nr_zones != q->nr_zones) {

                sd_zbc_cleanup(sdkp);

                q->nr_zones = sdkp->nr_zones;
                if (sdkp->nr_zones) {
                        q->seq_zones_wlock = sd_zbc_alloc_zone_bitmap(sdkp);
                        if (!q->seq_zones_wlock) {
                                ret = -ENOMEM;
                                goto err;
                        }

                        ret = sd_zbc_setup_seq_zones_bitmap(sdkp);
                        if (ret) {
                                sd_zbc_cleanup(sdkp);
                                goto err;
                        }
                }

        }

        return 0;

err:
        sd_zbc_cleanup(sdkp);
        return ret;
}

int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf)
{
        int ret;

        if (!sd_is_zoned(sdkp))
                /*
                 * Device managed or normal SCSI disk,
                 * no special handling required
                 */
                return 0;

        /* Get zoned block device characteristics */
        ret = sd_zbc_read_zoned_characteristics(sdkp, buf);
        if (ret)
                goto err;

        /*
         * Check for unconstrained reads: host-managed devices with
         * constrained reads (drives failing read after write pointer)
         * are not supported.
         */
        if (!sdkp->urswrz) {
                if (sdkp->first_scan)
                        sd_printk(KERN_NOTICE, sdkp,
                          "constrained reads devices are not supported\n");
                ret = -ENODEV;
                goto err;
        }

        /* Check capacity */
        ret = sd_zbc_check_capacity(sdkp, buf);
        if (ret)
                goto err;

        /*
         * Check zone size: only devices with a constant zone size (except
         * an eventual last runt zone) that is a power of 2 are supported.
         */
        ret = sd_zbc_check_zone_size(sdkp);
        if (ret)
                goto err;

        /* The drive satisfies the kernel restrictions: set it up */
        ret = sd_zbc_setup(sdkp);
        if (ret)
                goto err;

        return 0;

err:
        sdkp->capacity = 0;
        sd_zbc_cleanup(sdkp);

        return ret;
}

void sd_zbc_remove(struct scsi_disk *sdkp)
{
        sd_zbc_cleanup(sdkp);
}

void sd_zbc_print_zones(struct scsi_disk *sdkp)
{
        if (!sd_is_zoned(sdkp) || !sdkp->capacity)
                return;

        if (sdkp->capacity & (sdkp->zone_blocks - 1))
                sd_printk(KERN_NOTICE, sdkp,
                          "%u zones of %u logical blocks + 1 runt zone\n",
                          sdkp->nr_zones - 1,
                          sdkp->zone_blocks);
        else
                sd_printk(KERN_NOTICE, sdkp,
                          "%u zones of %u logical blocks\n",
                          sdkp->nr_zones,
                          sdkp->zone_blocks);
}