| /* |
| * splice engine |
| * |
| * IO engine that transfers data by doing splices to/from pipes and |
| * the files. |
| * |
| */ |
| #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_SPLICE |
| |
| struct spliceio_data { |
| int pipe[2]; |
| int vmsplice_to_user; |
| }; |
| |
| /* |
| * vmsplice didn't use to support splicing to user space, this is the old |
| * variant of getting that job done. Doesn't make a lot of sense, but it |
| * uses splices to move data from the source into a pipe. |
| */ |
| static int fio_splice_read_old(struct thread_data *td, struct io_u *io_u) |
| { |
| struct spliceio_data *sd = td->io_ops->data; |
| struct fio_file *f = io_u->file; |
| int ret, ret2, buflen; |
| off_t offset; |
| void *p; |
| |
| offset = io_u->offset; |
| buflen = io_u->xfer_buflen; |
| p = io_u->xfer_buf; |
| while (buflen) { |
| int this_len = buflen; |
| |
| if (this_len > SPLICE_DEF_SIZE) |
| this_len = SPLICE_DEF_SIZE; |
| |
| ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE); |
| if (ret < 0) { |
| if (errno == ENODATA || errno == EAGAIN) |
| continue; |
| |
| return -errno; |
| } |
| |
| buflen -= ret; |
| |
| while (ret) { |
| ret2 = read(sd->pipe[0], p, ret); |
| if (ret2 < 0) |
| return -errno; |
| |
| ret -= ret2; |
| p += ret2; |
| } |
| } |
| |
| return io_u->xfer_buflen; |
| } |
| |
| /* |
| * We can now vmsplice into userspace, so do the transfer by splicing into |
| * a pipe and vmsplicing that into userspace. |
| */ |
| static int fio_splice_read(struct thread_data *td, struct io_u *io_u) |
| { |
| struct spliceio_data *sd = td->io_ops->data; |
| struct fio_file *f = io_u->file; |
| struct iovec iov; |
| int ret, buflen; |
| off_t offset; |
| void *p; |
| |
| offset = io_u->offset; |
| buflen = io_u->xfer_buflen; |
| p = io_u->xfer_buf; |
| while (buflen) { |
| int this_len = buflen; |
| |
| if (this_len > SPLICE_DEF_SIZE) |
| this_len = SPLICE_DEF_SIZE; |
| |
| ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len, SPLICE_F_MORE); |
| if (ret < 0) { |
| if (errno == ENODATA || errno == EAGAIN) |
| continue; |
| |
| return -errno; |
| } |
| |
| buflen -= ret; |
| iov.iov_base = p; |
| iov.iov_len = ret; |
| p += ret; |
| |
| while (iov.iov_len) { |
| ret = vmsplice(sd->pipe[0], &iov, 1, SPLICE_F_MOVE); |
| if (ret < 0) |
| return -errno; |
| else if (!ret) |
| return -ENODATA; |
| |
| iov.iov_len -= ret; |
| iov.iov_base += ret; |
| } |
| } |
| |
| return io_u->xfer_buflen; |
| } |
| |
| |
| /* |
| * For splice writing, we can vmsplice our data buffer directly into a |
| * pipe and then splice that to a file. |
| */ |
| static int fio_splice_write(struct thread_data *td, struct io_u *io_u) |
| { |
| struct spliceio_data *sd = td->io_ops->data; |
| struct iovec iov = { |
| .iov_base = io_u->xfer_buf, |
| .iov_len = io_u->xfer_buflen, |
| }; |
| struct pollfd pfd = { .fd = sd->pipe[1], .events = POLLOUT, }; |
| struct fio_file *f = io_u->file; |
| off_t off = io_u->offset; |
| int ret, ret2; |
| |
| while (iov.iov_len) { |
| if (poll(&pfd, 1, -1) < 0) |
| return errno; |
| |
| ret = vmsplice(sd->pipe[1], &iov, 1, SPLICE_F_NONBLOCK); |
| if (ret < 0) |
| return -errno; |
| |
| iov.iov_len -= ret; |
| iov.iov_base += ret; |
| |
| while (ret) { |
| ret2 = splice(sd->pipe[0], NULL, f->fd, &off, ret, 0); |
| if (ret2 < 0) |
| return -errno; |
| |
| ret -= ret2; |
| } |
| } |
| |
| return io_u->xfer_buflen; |
| } |
| |
| static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u) |
| { |
| struct spliceio_data *sd = td->io_ops->data; |
| int ret; |
| |
| if (io_u->ddir == DDIR_READ) { |
| if (sd->vmsplice_to_user) |
| ret = fio_splice_read(td, io_u); |
| else |
| ret = fio_splice_read_old(td, io_u); |
| } else if (io_u->ddir == DDIR_WRITE) |
| ret = fio_splice_write(td, io_u); |
| else |
| ret = fsync(io_u->file->fd); |
| |
| if (ret != (int) io_u->xfer_buflen) { |
| if (ret >= 0) { |
| io_u->resid = io_u->xfer_buflen - ret; |
| io_u->error = 0; |
| return FIO_Q_COMPLETED; |
| } else |
| io_u->error = errno; |
| } |
| |
| if (io_u->error) |
| td_verror(td, io_u->error, "xfer"); |
| |
| return FIO_Q_COMPLETED; |
| } |
| |
| static void fio_spliceio_cleanup(struct thread_data *td) |
| { |
| struct spliceio_data *sd = td->io_ops->data; |
| |
| if (sd) { |
| close(sd->pipe[0]); |
| close(sd->pipe[1]); |
| free(sd); |
| td->io_ops->data = NULL; |
| } |
| } |
| |
| static int fio_spliceio_init(struct thread_data *td) |
| { |
| struct spliceio_data *sd = malloc(sizeof(*sd)); |
| |
| if (pipe(sd->pipe) < 0) { |
| td_verror(td, errno, "pipe"); |
| free(sd); |
| return 1; |
| } |
| |
| /* |
| * need some check for enabling this, for now just leave it disabled |
| */ |
| sd->vmsplice_to_user = 0; |
| |
| td->io_ops->data = sd; |
| return 0; |
| } |
| |
| static struct ioengine_ops ioengine = { |
| .name = "splice", |
| .version = FIO_IOOPS_VERSION, |
| .init = fio_spliceio_init, |
| .queue = fio_spliceio_queue, |
| .cleanup = fio_spliceio_cleanup, |
| .open_file = generic_open_file, |
| .close_file = generic_close_file, |
| .flags = FIO_SYNCIO, |
| }; |
| |
| #else /* FIO_HAVE_SPLICE */ |
| |
| /* |
| * 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_spliceio_init(struct thread_data fio_unused *td) |
| { |
| fprintf(stderr, "fio: splice not available\n"); |
| return 1; |
| } |
| |
| static struct ioengine_ops ioengine = { |
| .name = "splice", |
| .version = FIO_IOOPS_VERSION, |
| .init = fio_spliceio_init, |
| }; |
| |
| #endif |
| |
| static void fio_init fio_spliceio_register(void) |
| { |
| register_ioengine(&ioengine); |
| } |
| |
| static void fio_exit fio_spliceio_unregister(void) |
| { |
| unregister_ioengine(&ioengine); |
| } |