X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=engines%2Fsplice.c;h=feb764feb2f4f4766275dd53e938cab1ce3e5292;hp=432ba79b032d3381ce8114e92db6242ecfee2691;hb=2b9415ddc260726c3ea9ae3436826f9181811143;hpb=95bcd815e5ce55d6cdd8eb83bda5ee411f37bdc9

diff --git a/engines/splice.c b/engines/splice.c
index 432ba79b..feb764fe 100644
--- a/engines/splice.c
+++ b/engines/splice.c
@@ -1,60 +1,37 @@
 /*
- * splice io engine
+ * 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 <poll.h>
+#include <sys/mman.h>
 
 #include "../fio.h"
-#include "../os.h"
-
-#ifdef FIO_HAVE_SPLICE
 
 struct spliceio_data {
-	struct io_u *last_io_u;
 	int pipe[2];
+	int vmsplice_to_user;
+	int vmsplice_to_user_map;
 };
 
-static int fio_spliceio_getevents(struct thread_data *td, int fio_unused min,
-				  int max, struct timespec fio_unused *t)
-{
-	assert(max <= 1);
-
-	/*
-	 * we can only have one finished io_u for sync io, since the depth
-	 * is always 1
-	 */
-	if (list_empty(&td->io_u_busylist))
-		return 0;
-
-	return 1;
-}
-
-static struct io_u *fio_spliceio_event(struct thread_data *td, int event)
-{
-	struct spliceio_data *sd = td->io_ops->data;
-
-	assert(event == 0);
-
-	return sd->last_io_u;
-}
-
 /*
- * For splice reading, we unfortunately cannot (yet) vmsplice the other way.
- * So just splice the data from the file into the pipe, and use regular
- * read to fill the buffer. Doesn't make a lot of sense, but...
+ * 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(struct thread_data *td, struct io_u *io_u)
+static int fio_splice_read_old(struct thread_data *td, struct io_u *io_u)
 {
-	struct spliceio_data *sd = td->io_ops->data;
+	struct spliceio_data *sd = td->io_ops_data;
 	struct fio_file *f = io_u->file;
 	int ret, ret2, buflen;
 	off_t offset;
-	void *p;
+	char *p;
 
 	offset = io_u->offset;
 	buflen = io_u->xfer_buflen;
@@ -70,7 +47,7 @@ static int fio_splice_read(struct thread_data *td, struct io_u *io_u)
 			if (errno == ENODATA || errno == EAGAIN)
 				continue;
 
-			return errno;
+			return -errno;
 		}
 
 		buflen -= ret;
@@ -78,7 +55,7 @@ static int fio_splice_read(struct thread_data *td, struct io_u *io_u)
 		while (ret) {
 			ret2 = read(sd->pipe[0], p, ret);
 			if (ret2 < 0)
-				return errno;
+				return -errno;
 
 			ret -= ret2;
 			p += ret2;
@@ -88,39 +65,132 @@ static int fio_splice_read(struct thread_data *td, struct io_u *io_u)
 	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, mmap_len;
+	off_t offset;
+	void *map;
+	char *p;
+
+	ret = 0;
+	offset = io_u->offset;
+	mmap_len = buflen = io_u->xfer_buflen;
+
+	if (sd->vmsplice_to_user_map) {
+		map = mmap(io_u->xfer_buf, buflen, PROT_READ, MAP_PRIVATE|OS_MAP_ANON, 0, 0);
+		if (map == MAP_FAILED) {
+			td_verror(td, errno, "mmap io_u");
+			return -1;
+		}
+
+		p = map;
+	} else {
+		map = NULL;
+		p = io_u->xfer_buf;
+	}
+
+	while (buflen) {
+		int this_len = buflen;
+		int flags = 0;
+
+		if (this_len > SPLICE_DEF_SIZE) {
+			this_len = SPLICE_DEF_SIZE;
+			flags = SPLICE_F_MORE;
+		}
+
+		ret = splice(f->fd, &offset, sd->pipe[1], NULL, this_len,flags);
+		if (ret < 0) {
+			if (errno == ENODATA || errno == EAGAIN)
+				continue;
+
+			td_verror(td, errno, "splice-from-fd");
+			break;
+		}
+
+		buflen -= ret;
+		iov.iov_base = p;
+		iov.iov_len = ret;
+
+		while (iov.iov_len) {
+			ret = vmsplice(sd->pipe[0], &iov, 1, SPLICE_F_MOVE);
+			if (ret < 0) {
+				if (errno == EFAULT &&
+				    sd->vmsplice_to_user_map) {
+					sd->vmsplice_to_user_map = 0;
+					munmap(map, mmap_len);
+					map = NULL;
+					p = io_u->xfer_buf;
+					iov.iov_base = p;
+					continue;
+				}
+				if (errno == EBADF) {
+					ret = -EBADF;
+					break;
+				}
+				td_verror(td, errno, "vmsplice");
+				break;
+			} else if (!ret) {
+				td_verror(td, ENODATA, "vmsplice");
+				ret = -1;
+				break;
+			}
+
+			iov.iov_len -= ret;
+			iov.iov_base += ret;
+			p += ret;
+		}
+		if (ret < 0)
+			break;
+	}
+
+	if (sd->vmsplice_to_user_map && munmap(map, mmap_len) < 0) {
+		td_verror(td, errno, "munnap io_u");
+		return -1;
+	}
+	if (ret < 0)
+		return 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[1] = {
-		{
-			.iov_base = io_u->xfer_buf,
-			.iov_len = io_u->xfer_buflen,
-		}
+	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[0].iov_len) {
+	while (iov.iov_len) {
 		if (poll(&pfd, 1, -1) < 0)
 			return errno;
 
-		ret = vmsplice(sd->pipe[1], iov, 1, SPLICE_F_NONBLOCK);
+		ret = vmsplice(sd->pipe[1], &iov, 1, SPLICE_F_NONBLOCK);
 		if (ret < 0)
-			return errno;
+			return -errno;
 
-		iov[0].iov_len -= ret;
-		iov[0].iov_base += ret;
+		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;
+				return -errno;
 
 			ret -= ret2;
 		}
@@ -129,44 +199,61 @@ static int fio_splice_write(struct thread_data *td, struct io_u *io_u)
 	return io_u->xfer_buflen;
 }
 
-static int fio_spliceio_queue(struct thread_data *td, struct io_u *io_u)
+static enum fio_q_status 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)
-		ret = fio_splice_read(td, io_u);
-	else if (io_u->ddir == DDIR_WRITE)
+	struct spliceio_data *sd = td->io_ops_data;
+	int ret = 0;
+
+	fio_ro_check(td, io_u);
+
+	if (io_u->ddir == DDIR_READ) {
+		if (sd->vmsplice_to_user) {
+			ret = fio_splice_read(td, io_u);
+			/*
+			 * This kernel doesn't support vmsplice to user
+			 * space. Reset the vmsplice_to_user flag, so that
+			 * we retry below and don't hit this path again.
+			 */
+			if (ret == -EBADF)
+				sd->vmsplice_to_user = 0;
+		}
+		if (!sd->vmsplice_to_user)
+			ret = fio_splice_read_old(td, io_u);
+	} else if (io_u->ddir == DDIR_WRITE)
 		ret = fio_splice_write(td, io_u);
+	else if (io_u->ddir == DDIR_TRIM)
+		ret = do_io_u_trim(td, io_u);
 	else
-		ret = fsync(io_u->file->fd);
+		ret = do_io_u_sync(td, io_u);
 
 	if (ret != (int) io_u->xfer_buflen) {
-		if (ret > 0) {
+		if (ret >= 0) {
 			io_u->resid = io_u->xfer_buflen - ret;
 			io_u->error = 0;
-			return ret;
+			return FIO_Q_COMPLETED;
 		} else
 			io_u->error = errno;
 	}
 
-	if (!io_u->error)
-		sd->last_io_u = io_u;
-	else
-		td_verror(td, io_u->error);
+	if (io_u->error) {
+		td_verror(td, io_u->error, "xfer");
+		if (io_u->error == EINVAL)
+			log_err("fio: looks like splice doesn't work on this"
+					" file system\n");
+	}
 
-	return io_u->error;
+	return FIO_Q_COMPLETED;
 }
 
 static void fio_spliceio_cleanup(struct thread_data *td)
 {
-	struct spliceio_data *sd = td->io_ops->data;
+	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;
 	}
 }
 
@@ -174,49 +261,46 @@ static int fio_spliceio_init(struct thread_data *td)
 {
 	struct spliceio_data *sd = malloc(sizeof(*sd));
 
-	sd->last_io_u = NULL;
 	if (pipe(sd->pipe) < 0) {
-		td_verror(td, errno);
+		td_verror(td, errno, "pipe");
 		free(sd);
 		return 1;
 	}
 
-	td->io_ops->data = sd;
-	return 0;
-}
+	/*
+	 * Assume this work, we'll reset this if it doesn't
+	 */
+	sd->vmsplice_to_user = 1;
 
-static struct ioengine_ops ioengine = {
-	.name		= "splice",
-	.version	= FIO_IOOPS_VERSION,
-	.init		= fio_spliceio_init,
-	.queue		= fio_spliceio_queue,
-	.getevents	= fio_spliceio_getevents,
-	.event		= fio_spliceio_event,
-	.cleanup	= fio_spliceio_cleanup,
-	.flags		= FIO_SYNCIO,
-};
+	/*
+	 * Works with "real" vmsplice to user, eg mapping pages directly.
+	 * Reset if we fail.
+	 */
+	sd->vmsplice_to_user_map = 1;
 
-#else /* FIO_HAVE_SPLICE */
+	/*
+	 * And if vmsplice_to_user works, we definitely need aligned
+	 * buffers. Just set ->odirect to force that.
+	 */
+	if (td_read(td))
+		td->o.mem_align = 1;
 
-/*
- * 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;
+	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,
+	.get_file_size	= generic_get_file_size,
+	.flags		= FIO_SYNCIO | FIO_PIPEIO,
 };
 
-#endif
-
 static void fio_init fio_spliceio_register(void)
 {
 	register_ioengine(&ioengine);