From 0af7b542b69af5ab2400a9960a5bcde82c05723f Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@suse.de>
Date: Fri, 17 Feb 2006 10:10:12 +0100
Subject: [PATCH] [PATCH] Add support for the read/write interface of SG v3

---
 fio-ini.c |  8 ++++--
 fio-io.c  | 80 ++++++++++++++++++++++++++++++++++++++++++++++---------
 fio.c     | 17 ++++++++----
 fio.h     |  1 +
 4 files changed, 86 insertions(+), 20 deletions(-)

diff --git a/fio-ini.c b/fio-ini.c
index 23405898..c9406227 100644
--- a/fio-ini.c
+++ b/fio-ini.c
@@ -204,8 +204,12 @@ static int add_job(struct thread_data *td, const char *jobname, int prioclass,
 		td->zone_size = 0;
 
 	td->filetype = FIO_TYPE_FILE;
-	if (!stat(jobname, &sb) && S_ISBLK(sb.st_mode))
-		td->filetype = FIO_TYPE_BD;
+	if (!stat(jobname, &sb)) {
+		if (S_ISBLK(sb.st_mode))
+			td->filetype = FIO_TYPE_BD;
+		else if (S_ISCHR(sb.st_mode))
+			td->filetype = FIO_TYPE_CHAR;
+	}
 
 	if (td->filetype == FIO_TYPE_FILE) {
 		if (td->directory[0] != '\0')
diff --git a/fio-io.c b/fio-io.c
index dee02ab5..b688fa28 100644
--- a/fio-io.c
+++ b/fio-io.c
@@ -481,6 +481,24 @@ static inline void sgio_hdr_init(struct sgio_data *sd, struct sg_io_hdr *hdr,
 	}
 }
 
+static int fio_sgio_doio(struct thread_data *td, struct sg_io_hdr *hdr)
+{
+	int ret;
+
+	if (td->filetype == FIO_TYPE_BD)
+		return ioctl(td->fd, SG_IO, &hdr);
+
+	ret = write(td->fd, hdr, sizeof(*hdr));
+	if (ret < 0)
+		return errno;
+
+	ret = read(td->fd, hdr, sizeof(*hdr));
+	if (ret < 0)
+		return errno;
+
+	return 0;
+}
+
 static int fio_sgio_sync(struct thread_data *td)
 {
 	struct sgio_data *sd = td->io_data;
@@ -491,7 +509,7 @@ static int fio_sgio_sync(struct thread_data *td)
 
 	hdr.cmdp[0] = 0x35;
 
-	return ioctl(td->fd, SG_IO, &hdr);
+	return fio_sgio_doio(td, &hdr);
 }
 
 static int fio_sgio_prep(struct thread_data *td, struct io_u *io_u)
@@ -532,7 +550,8 @@ static int fio_sgio_queue(struct thread_data *td, struct io_u *io_u)
 	struct sgio_data *sd = td->io_data;
 	int ret;
 
-	ret = ioctl(td->fd, SG_IO, hdr);
+	ret = fio_sgio_doio(td, hdr);
+
 	if (ret < 0)
 		io_u->error = errno;
 	else if (hdr->status) {
@@ -555,22 +574,60 @@ static struct io_u *fio_sgio_event(struct thread_data *td, int event)
 	return sd->last_io_u;
 }
 
+static int fio_sgio_get_bs(struct thread_data *td, unsigned int *bs)
+{
+	struct sgio_data *sd = td->io_data;
+	struct sg_io_hdr hdr;
+	unsigned char buf[8];
+	int ret;
+
+	sgio_hdr_init(sd, &hdr, NULL);
+	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, &hdr);
+	if (ret)
+		return ret;
+
+	*bs = (buf[4] << 24) | (buf[5] << 16) | (buf[6] << 8) | buf[7];
+	return 0;
+}
+
 int fio_sgio_init(struct thread_data *td)
 {
 	struct sgio_data *sd;
-	int bs;
+	unsigned int bs;
+	int ret;
 
-	if (td->filetype != FIO_TYPE_BD) {
-		fprintf(stderr, "ioengine sgio only works on block devices\n");
-		return 1;
-	}
+	sd = malloc(sizeof(*sd));
+	sd->last_io_u = NULL;
+	td->io_data = sd;
 
-	if (ioctl(td->fd, BLKSSZGET, &bs) < 0) {
-		td_verror(td, errno);
+	if (td->filetype == FIO_TYPE_BD) {
+		if (ioctl(td->fd, BLKSSZGET, &bs) < 0) {
+			td_verror(td, errno);
+			return 1;
+		}
+	} else if (td->filetype == FIO_TYPE_CHAR) {
+		int version;
+
+		if (ioctl(td->fd, SG_GET_VERSION_NUM, &version) < 0) {
+			td_verror(td, errno);
+			return 1;
+		}
+
+		ret = fio_sgio_get_bs(td, &bs);
+		if (ret)
+			return ret;
+	} else {
+		fprintf(stderr, "ioengine sgio only works on block devices\n");
 		return 1;
 	}
 
-	sd = malloc(sizeof(*sd));
 	sd->bs = bs;
 
 	td->io_prep = fio_sgio_prep;
@@ -585,9 +642,6 @@ int fio_sgio_init(struct thread_data *td)
 	 * we want to do it, regardless of whether odirect is set or not
 	 */
 	td->override_sync = 1;
-
-	sd->last_io_u = NULL;
-	td->io_data = sd;
 	return 0;
 }
 
diff --git a/fio.c b/fio.c
index 9dd8e249..5c45cae7 100644
--- a/fio.c
+++ b/fio.c
@@ -1235,12 +1235,14 @@ static int bdev_size(struct thread_data *td)
 
 static int get_file_size(struct thread_data *td)
 {
-	int ret;
+	int ret = 0;
 
 	if (td->filetype == FIO_TYPE_FILE)
 		ret = file_size(td);
-	else
+	else if (td->filetype == FIO_TYPE_BD)
 		ret = bdev_size(td);
+	else
+		td->real_file_size = -1;
 
 	if (ret)
 		return ret;
@@ -1356,9 +1358,14 @@ static int setup_file(struct thread_data *td)
 	if (td->odirect)
 		flags |= O_DIRECT;
 
-	if (td_read(td))
-		td->fd = open(td->file_name, flags | O_RDONLY);
-	else {
+	if (td_read(td)) {
+		if (td->filetype == FIO_TYPE_CHAR)
+			flags |= O_RDWR;
+		else
+			flags |= O_RDONLY;
+
+		td->fd = open(td->file_name, flags);
+	} else {
 		if (td->filetype == FIO_TYPE_FILE) {
 			if (!td->overwrite)
 				flags |= O_TRUNC;
diff --git a/fio.h b/fio.h
index bb5b8dd1..5fcdfddb 100644
--- a/fio.h
+++ b/fio.h
@@ -259,6 +259,7 @@ enum {
 enum {
 	FIO_TYPE_FILE = 1,
 	FIO_TYPE_BD,
+	FIO_TYPE_CHAR,
 };
 
 enum {
-- 
2.25.1