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sg.c

/*
 * sg engine
 *
 * IO engine that uses the Linux SG v3 interface to talk to SCSI devices
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <sys/poll.h>

#include "../fio.h"

#ifdef FIO_HAVE_SGIO

struct sgio_cmd {
      unsigned char cdb[10];
      int nr;
};

struct sgio_data {
      struct sgio_cmd *cmds;
      struct io_u **events;
      struct pollfd *pfds;
      int *fd_flags;
      void *sgbuf;
      unsigned int bs;
      int type_checked;
};

static void sgio_hdr_init(struct sgio_data *sd, struct sg_io_hdr *hdr,
                    struct io_u *io_u, int fs)
{
      struct sgio_cmd *sc = &sd->cmds[io_u->index];

      memset(hdr, 0, sizeof(*hdr));
      memset(sc->cdb, 0, sizeof(sc->cdb));

      hdr->interface_id = 'S';
      hdr->cmdp = sc->cdb;
      hdr->cmd_len = sizeof(sc->cdb);
      hdr->pack_id = io_u->index;
      hdr->usr_ptr = io_u;

      if (fs) {
            hdr->dxferp = io_u->xfer_buf;
            hdr->dxfer_len = io_u->xfer_buflen;
      }
}

static int pollin_events(struct pollfd *pfds, int fds)
{
      int i;

      for (i = 0; i < fds; i++)
            if (pfds[i].revents & POLLIN)
                  return 1;

      return 0;
}

static int fio_sgio_getevents(struct thread_data *td, unsigned int min,
                        unsigned int max, struct timespec fio_unused *t)
{
      struct sgio_data *sd = td->io_ops->data;
      int left = max, ret, r = 0;
      void *buf = sd->sgbuf;
      unsigned int i, events;
      struct fio_file *f;

      /*
       * Fill in the file descriptors
       */
      for_each_file(td, f, i) {
            /*
             * don't block for min events == 0
             */
            if (!min) {
                  sd->fd_flags[i] = fcntl(f->fd, F_GETFL);
                  fcntl(f->fd, F_SETFL, sd->fd_flags[i] | O_NONBLOCK);
            }
            sd->pfds[i].fd = f->fd;
            sd->pfds[i].events = POLLIN;
      }

      while (left) {
            void *p;

            do {
                  if (!min)
                        break;

                  ret = poll(sd->pfds, td->o.nr_files, -1);
                  if (ret < 0) {
                        if (!r)
                              r = -errno;
                        td_verror(td, errno, "poll");
                        break;
                  } else if (!ret)
                        continue;

                  if (pollin_events(sd->pfds, td->o.nr_files))
                        break;
            } while (1);

            if (r < 0)
                  break;

re_read:
            p = buf;
            events = 0;
            for_each_file(td, f, i) {
                  ret = read(f->fd, p, left * sizeof(struct sg_io_hdr));
                  if (ret < 0) {
                        if (errno == EAGAIN)
                              continue;
                        r = -errno;
                        td_verror(td, errno, "read");
                        break;
                  } else if (ret) {
                        p += ret;
                        events += ret / sizeof(struct sg_io_hdr);
                  }
            }

            if (r < 0)
                  break;
            if (!events) {
                  usleep(1000);
                  goto re_read;
            }

            left -= events;
            r += events;

            for (i = 0; i < events; i++) {
                  struct sg_io_hdr *hdr = (struct sg_io_hdr *) buf + i;

                  sd->events[i] = hdr->usr_ptr;
            }
      }

      if (!min) {
            for_each_file(td, f, i)
                  fcntl(f->fd, F_SETFL, sd->fd_flags[i]);
      }

      return r;
}

static int fio_sgio_ioctl_doio(struct thread_data *td,
                         struct fio_file *f, struct io_u *io_u)
{
      struct sgio_data *sd = td->io_ops->data;
      struct sg_io_hdr *hdr = &io_u->hdr;
      int ret;

      sd->events[0] = io_u;

      ret = ioctl(f->fd, SG_IO, hdr);
      if (ret < 0)
            return ret;

      return FIO_Q_COMPLETED;
}

static int fio_sgio_rw_doio(struct fio_file *f, struct io_u *io_u, int sync)
{
      struct sg_io_hdr *hdr = &io_u->hdr;
      int ret;

      ret = write(f->fd, hdr, sizeof(*hdr));
      if (ret < 0)
            return ret;

      if (sync) {
            ret = read(f->fd, hdr, sizeof(*hdr));
            if (ret < 0)
                  return ret;
            return FIO_Q_COMPLETED;
      }

      return FIO_Q_QUEUED;
}

static int fio_sgio_doio(struct thread_data *td, struct io_u *io_u, int sync)
{
      struct fio_file *f = io_u->file;

      if (f->filetype == FIO_TYPE_BD)
            return fio_sgio_ioctl_doio(td, f, io_u);

      return fio_sgio_rw_doio(f, io_u, sync);
}

static int fio_sgio_prep(struct thread_data *td, struct io_u *io_u)
{
      struct sg_io_hdr *hdr = &io_u->hdr;
      struct sgio_data *sd = td->io_ops->data;
      int nr_blocks, lba;

      if (io_u->xfer_buflen & (sd->bs - 1)) {
            log_err("read/write not sector aligned\n");
            return EINVAL;
      }

      if (io_u->ddir == DDIR_READ) {
            sgio_hdr_init(sd, hdr, io_u, 1);

            hdr->dxfer_direction = SG_DXFER_FROM_DEV;
            hdr->cmdp[0] = 0x28;
      } else if (io_u->ddir == DDIR_WRITE) {
            sgio_hdr_init(sd, hdr, io_u, 1);

            hdr->dxfer_direction = SG_DXFER_TO_DEV;
            hdr->cmdp[0] = 0x2a;
      } else {
            sgio_hdr_init(sd, hdr, io_u, 0);

            hdr->dxfer_direction = SG_DXFER_NONE;
            hdr->cmdp[0] = 0x35;
      }

      if (hdr->dxfer_direction != SG_DXFER_NONE) {
            nr_blocks = io_u->xfer_buflen / sd->bs;
            lba = io_u->offset / sd->bs;
            hdr->cmdp[2] = (unsigned char) ((lba >> 24) & 0xff);
            hdr->cmdp[3] = (unsigned char) ((lba >> 16) & 0xff);
            hdr->cmdp[4] = (unsigned char) ((lba >>  8) & 0xff);
            hdr->cmdp[5] = (unsigned char) (lba & 0xff);
            hdr->cmdp[7] = (unsigned char) ((nr_blocks >> 8) & 0xff);
            hdr->cmdp[8] = (unsigned char) (nr_blocks & 0xff);
      }

      return 0;
}

static int fio_sgio_queue(struct thread_data *td, struct io_u *io_u)
{
      struct sg_io_hdr *hdr = &io_u->hdr;
      int ret, do_sync = 0;

      fio_ro_check(td, io_u);

      if (td->o.sync_io || td->o.odirect || ddir_sync(io_u->ddir))
            do_sync = 1;

      ret = fio_sgio_doio(td, io_u, do_sync);

      if (ret < 0)
            io_u->error = errno;
      else if (hdr->status) {
            io_u->resid = hdr->resid;
            io_u->error = EIO;
      }

      if (io_u->error) {
            td_verror(td, io_u->error, "xfer");
            return FIO_Q_COMPLETED;
      }

      return ret;
}

static struct io_u *fio_sgio_event(struct thread_data *td, int event)
{
      struct sgio_data *sd = td->io_ops->data;

      return sd->events[event];
}

static int fio_sgio_get_bs(struct thread_data *td, unsigned int *bs)
{
      struct sgio_data *sd = td->io_ops->data;
      struct io_u *io_u;
      struct sg_io_hdr *hdr;
      unsigned char buf[8];
      int ret;

      io_u = __get_io_u(td);
      io_u->file = td->files[0];
      assert(io_u);

      hdr = &io_u->hdr;
      sgio_hdr_init(sd, hdr, io_u, 0);
      memset(buf, 0, sizeof(buf));

      hdr->cmdp[0] = 0x25;
      hdr->dxfer_direction = SG_DXFER_FROM_DEV;
      hdr->dxferp = buf;
      hdr->dxfer_len = sizeof(buf);

      ret = fio_sgio_doio(td, io_u, 1);
      if (ret) {
            put_io_u(td, io_u);
            return ret;
      }

      *bs = (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
      put_io_u(td, io_u);
      return 0;
}

static void fio_sgio_cleanup(struct thread_data *td)
{
      struct sgio_data *sd = td->io_ops->data;

      if (sd) {
            free(sd->events);
            free(sd->cmds);
            free(sd->fd_flags);
            free(sd->pfds);
            free(sd->sgbuf);
            free(sd);
      }
}

static int fio_sgio_init(struct thread_data *td)
{
      struct sgio_data *sd;

      sd = malloc(sizeof(*sd));
      memset(sd, 0, sizeof(*sd));
      sd->cmds = malloc(td->o.iodepth * sizeof(struct sgio_cmd));
      memset(sd->cmds, 0, td->o.iodepth * sizeof(struct sgio_cmd));
      sd->events = malloc(td->o.iodepth * sizeof(struct io_u *));
      memset(sd->events, 0, td->o.iodepth * sizeof(struct io_u *));
      sd->pfds = malloc(sizeof(struct pollfd) * td->o.nr_files);
      memset(sd->pfds, 0, sizeof(struct pollfd) * td->o.nr_files);
      sd->fd_flags = malloc(sizeof(int) * td->o.nr_files);
      memset(sd->fd_flags, 0, sizeof(int) * td->o.nr_files);
      sd->sgbuf = malloc(sizeof(struct sg_io_hdr) * td->o.iodepth);
      memset(sd->sgbuf, 0, sizeof(struct sg_io_hdr) * td->o.iodepth);

      td->io_ops->data = sd;

      /*
       * we want to do it, regardless of whether odirect is set or not
       */
      td->o.override_sync = 1;
      return 0;
}

static int fio_sgio_type_check(struct thread_data *td, struct fio_file *f)
{
      struct sgio_data *sd = td->io_ops->data;
      unsigned int bs;

      if (f->filetype == FIO_TYPE_BD) {
            if (ioctl(f->fd, BLKSSZGET, &bs) < 0) {
                  td_verror(td, errno, "ioctl");
                  return 1;
            }
      } else if (f->filetype == FIO_TYPE_CHAR) {
            int version, ret;

            if (ioctl(f->fd, SG_GET_VERSION_NUM, &version) < 0) {
                  td_verror(td, errno, "ioctl");
                  return 1;
            }

            ret = fio_sgio_get_bs(td, &bs);
            if (ret)
                  return 1;
      } else {
            log_err("ioengine sg only works on block devices\n");
            return 1;
      }

      sd->bs = bs;

      if (f->filetype == FIO_TYPE_BD) {
            td->io_ops->getevents = NULL;
            td->io_ops->event = NULL;
      }

      return 0;
}

static int fio_sgio_open(struct thread_data *td, struct fio_file *f)
{
      struct sgio_data *sd = td->io_ops->data;
      int ret;

      ret = generic_open_file(td, f);
      if (ret)
            return ret;

      if (sd && !sd->type_checked && fio_sgio_type_check(td, f)) {
            ret = generic_close_file(td, f);
            return 1;
      }

      return 0;
}

static struct ioengine_ops ioengine = {
      .name       = "sg",
      .version    = FIO_IOOPS_VERSION,
      .init       = fio_sgio_init,
      .prep       = fio_sgio_prep,
      .queue            = fio_sgio_queue,
      .getevents  = fio_sgio_getevents,
      .event            = fio_sgio_event,
      .cleanup    = fio_sgio_cleanup,
      .open_file  = fio_sgio_open,
      .close_file = generic_close_file,
      .get_file_size    = generic_get_file_size,
      .flags            = FIO_SYNCIO | FIO_RAWIO,
};

#else /* FIO_HAVE_SGIO */

/*
 * When we have a proper configure system in place, we simply wont build
 * and install this io engine. For now install a crippled version that
 * just complains and fails to load.
 */
static int fio_sgio_init(struct thread_data fio_unused *td)
{
      fprintf(stderr, "fio: ioengine sg not available\n");
      return 1;
}

static struct ioengine_ops ioengine = {
      .name       = "sg",
      .version    = FIO_IOOPS_VERSION,
      .init       = fio_sgio_init,
};

#endif

static void fio_init fio_sgio_register(void)
{
      register_ioengine(&ioengine);
}

static void fio_exit fio_sgio_unregister(void)
{
      unregister_ioengine(&ioengine);
}

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