remove exofs, the T10 OSD code and block/scsi bidi support V4

remove exofs, the T10 OSD code and block/scsi bidi support V4

[Christoph Hellwig]

The only real user of the T10 OSD protocol, the pNFS object layout
driver never went to the point of having shipping products, and we
removed it 1.5 years ago.  Exofs is just a simple example without
real life users.

The code has been mostly unmaintained for years and is getting in the
way of block / SCSI changes, and does not even work properly currently,
so I think it's finally time to drop it.

Quote from Boaz:

"As I said then. It is used in Universities for studies and experiments.
Every once in a while. I get an email with questions and reports.

But yes feel free to remove the all thing!!

I guess I can put it up on github. In a public tree.

Just that I will need to forward port it myself, til now you guys
been doing this for me ;-)"

Now the last time this caused a bit of a stir, but still no actual users,
not even for SG_IO passthrough commands.  So here we go again, this time
including removing everything in the scsi and block layer supporting it,
and thus shrinking struct request.

[PATCH 1/8] bsg: refactor bsg_ioctl

[Christoph Hellwig]

Move all actual functionality into helpers, just leaving the dispatch
in this function.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Benjamin Block <bblock@linux.ibm.com>
Tested-by: Benjamin Block <bblock@linux.ibm.com>
Tested-by: Avri Altman <avri.altman@wdc.com>
---
 block/bsg.c | 158 ++++++++++++++++++++++++----------------------------
 1 file changed, 72 insertions(+), 86 deletions(-)

diff --git a/block/bsg.c b/block/bsg.c
index 50e5f8f666f2..a799b0ace55c 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -138,32 +138,35 @@ static const struct bsg_ops bsg_scsi_ops = {
 	.free_rq		= bsg_scsi_free_rq,
 };
 
-static struct request *
-bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
+static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 {
 	struct request *rq, *next_rq = NULL;
+	struct bio *bio, *bidi_bio = NULL;
+	struct sg_io_v4 hdr;
 	int ret;
 
-	if (!q->bsg_dev.class_dev)
-		return ERR_PTR(-ENXIO);
+	if (copy_from_user(&hdr, uarg, sizeof(hdr)))
+		return -EFAULT;
 
-	if (hdr->guard != 'Q')
-		return ERR_PTR(-EINVAL);
+	if (!q->bsg_dev.class_dev)
+		return -ENXIO;
 
-	ret = q->bsg_dev.ops->check_proto(hdr);
+	if (hdr.guard != 'Q')
+		return -EINVAL;
+	ret = q->bsg_dev.ops->check_proto(&hdr);
 	if (ret)
-		return ERR_PTR(ret);
+		return ret;
 
-	rq = blk_get_request(q, hdr->dout_xfer_len ?
+	rq = blk_get_request(q, hdr.dout_xfer_len ?
 			REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN, 0);
 	if (IS_ERR(rq))
-		return rq;
+		return PTR_ERR(rq);
 
-	ret = q->bsg_dev.ops->fill_hdr(rq, hdr, mode);
+	ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
 	if (ret)
 		goto out;
 
-	rq->timeout = msecs_to_jiffies(hdr->timeout);
+	rq->timeout = msecs_to_jiffies(hdr.timeout);
 	if (!rq->timeout)
 		rq->timeout = q->sg_timeout;
 	if (!rq->timeout)
@@ -171,7 +174,7 @@ bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
 	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
 		rq->timeout = BLK_MIN_SG_TIMEOUT;
 
-	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+	if (hdr.dout_xfer_len && hdr.din_xfer_len) {
 		if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
 			ret = -EOPNOTSUPP;
 			goto out;
@@ -188,42 +191,29 @@ bsg_map_hdr(struct request_queue *q, struct sg_io_v4 *hdr, fmode_t mode)
 		}
 
 		rq->next_rq = next_rq;
-		ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr->din_xferp),
-				       hdr->din_xfer_len, GFP_KERNEL);
+		ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr.din_xferp),
+				       hdr.din_xfer_len, GFP_KERNEL);
 		if (ret)
 			goto out_free_nextrq;
 	}
 
-	if (hdr->dout_xfer_len) {
-		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->dout_xferp),
-				hdr->dout_xfer_len, GFP_KERNEL);
-	} else if (hdr->din_xfer_len) {
-		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr->din_xferp),
-				hdr->din_xfer_len, GFP_KERNEL);
+	if (hdr.dout_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
+				hdr.dout_xfer_len, GFP_KERNEL);
+	} else if (hdr.din_xfer_len) {
+		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.din_xferp),
+				hdr.din_xfer_len, GFP_KERNEL);
 	}
 
 	if (ret)
 		goto out_unmap_nextrq;
-	return rq;
 
-out_unmap_nextrq:
+	bio = rq->bio;
 	if (rq->next_rq)
-		blk_rq_unmap_user(rq->next_rq->bio);
-out_free_nextrq:
-	if (rq->next_rq)
-		blk_put_request(rq->next_rq);
-out:
-	q->bsg_dev.ops->free_rq(rq);
-	blk_put_request(rq);
-	return ERR_PTR(ret);
-}
-
-static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
-				    struct bio *bio, struct bio *bidi_bio)
-{
-	int ret;
+		bidi_bio = rq->next_rq->bio;
 
-	ret = rq->q->bsg_dev.ops->complete_rq(rq, hdr);
+	blk_execute_rq(q, NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
+	ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
 
 	if (rq->next_rq) {
 		blk_rq_unmap_user(bidi_bio);
@@ -233,6 +223,20 @@ static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr,
 	blk_rq_unmap_user(bio);
 	rq->q->bsg_dev.ops->free_rq(rq);
 	blk_put_request(rq);
+
+	if (copy_to_user(uarg, &hdr, sizeof(hdr)))
+		return -EFAULT;
+	return ret;
+
+out_unmap_nextrq:
+	if (rq->next_rq)
+		blk_rq_unmap_user(rq->next_rq->bio);
+out_free_nextrq:
+	if (rq->next_rq)
+		blk_put_request(rq->next_rq);
+out:
+	q->bsg_dev.ops->free_rq(rq);
+	blk_put_request(rq);
 	return ret;
 }
 
@@ -367,31 +371,39 @@ static int bsg_release(struct inode *inode, struct file *file)
 	return bsg_put_device(bd);
 }
 
+static int bsg_get_command_q(struct bsg_device *bd, int __user *uarg)
+{
+	return put_user(bd->max_queue, uarg);
+}
+
+static int bsg_set_command_q(struct bsg_device *bd, int __user *uarg)
+{
+	int queue;
+
+	if (get_user(queue, uarg))
+		return -EFAULT;
+	if (queue < 1)
+		return -EINVAL;
+
+	spin_lock_irq(&bd->lock);
+	bd->max_queue = queue;
+	spin_unlock_irq(&bd->lock);
+	return 0;
+}
+
 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 {
 	struct bsg_device *bd = file->private_data;
-	int __user *uarg = (int __user *) arg;
-	int ret;
+	void __user *uarg = (void __user *) arg;
 
 	switch (cmd) {
-		/*
-		 * our own ioctls
-		 */
+	/*
+	 * Our own ioctls
+	 */
 	case SG_GET_COMMAND_Q:
-		return put_user(bd->max_queue, uarg);
-	case SG_SET_COMMAND_Q: {
-		int queue;
-
-		if (get_user(queue, uarg))
-			return -EFAULT;
-		if (queue < 1)
-			return -EINVAL;
-
-		spin_lock_irq(&bd->lock);
-		bd->max_queue = queue;
-		spin_unlock_irq(&bd->lock);
-		return 0;
-	}
+		return bsg_get_command_q(bd, uarg);
+	case SG_SET_COMMAND_Q:
+		return bsg_set_command_q(bd, uarg);
 
 	/*
 	 * SCSI/sg ioctls
@@ -404,36 +416,10 @@ static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case SG_GET_RESERVED_SIZE:
 	case SG_SET_RESERVED_SIZE:
 	case SG_EMULATED_HOST:
-	case SCSI_IOCTL_SEND_COMMAND: {
-		void __user *uarg = (void __user *) arg;
+	case SCSI_IOCTL_SEND_COMMAND:
 		return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg);
-	}
-	case SG_IO: {
-		struct request *rq;
-		struct bio *bio, *bidi_bio = NULL;
-		struct sg_io_v4 hdr;
-		int at_head;
-
-		if (copy_from_user(&hdr, uarg, sizeof(hdr)))
-			return -EFAULT;
-
-		rq = bsg_map_hdr(bd->queue, &hdr, file->f_mode);
-		if (IS_ERR(rq))
-			return PTR_ERR(rq);
-
-		bio = rq->bio;
-		if (rq->next_rq)
-			bidi_bio = rq->next_rq->bio;
-
-		at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL));
-		blk_execute_rq(bd->queue, NULL, rq, at_head);
-		ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio);
-
-		if (copy_to_user(uarg, &hdr, sizeof(hdr)))
-			return -EFAULT;
-
-		return ret;
-	}
+	case SG_IO:
+		return bsg_sg_io(bd->queue, file->f_mode, uarg);
 	default:
 		return -ENOTTY;
 	}
-- 
2.20.1

[PATCH 2/8] bsg-lib: handle bidi requests without block layer help

[Christoph Hellwig]

We can just stash away the second request in struct bsg_job instead
of using the block layer req->next_rq field, allowing for the eventual
removal of the latter.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/bsg-lib.c                   | 44 +++++++++++++++++---
 block/bsg.c                       | 68 +++++++------------------------
 drivers/scsi/scsi_transport_sas.c |  1 -
 include/linux/bsg-lib.h           |  4 ++
 4 files changed, 56 insertions(+), 61 deletions(-)

diff --git a/block/bsg-lib.c b/block/bsg-lib.c
index 192129856342..005e2b75d775 100644
--- a/block/bsg-lib.c
+++ b/block/bsg-lib.c
@@ -51,11 +51,40 @@ static int bsg_transport_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
 		fmode_t mode)
 {
 	struct bsg_job *job = blk_mq_rq_to_pdu(rq);
+	int ret;
 
 	job->request_len = hdr->request_len;
 	job->request = memdup_user(uptr64(hdr->request), hdr->request_len);
+	if (IS_ERR(job->request))
+		return PTR_ERR(job->request);
+
+	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+		job->bidi_rq = blk_get_request(rq->q, REQ_OP_SCSI_IN, 0);
+		if (IS_ERR(job->bidi_rq)) {
+			ret = PTR_ERR(job->bidi_rq);
+			goto out;
+		}
+
+		ret = blk_rq_map_user(rq->q, job->bidi_rq, NULL,
+				uptr64(hdr->din_xferp), hdr->din_xfer_len,
+				GFP_KERNEL);
+		if (ret)
+			goto out_free_bidi_rq;
+
+		job->bidi_bio = job->bidi_rq->bio;
+	} else {
+		job->bidi_rq = NULL;
+		job->bidi_bio = NULL;
+	}
 
-	return PTR_ERR_OR_ZERO(job->request);
+	return 0;
+
+out_free_bidi_rq:
+	if (job->bidi_rq)
+		blk_put_request(job->bidi_rq);
+out:
+	kfree(job->request);
+	return ret;
 }
 
 static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
@@ -93,7 +122,7 @@ static int bsg_transport_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
 	/* we assume all request payload was transferred, residual == 0 */
 	hdr->dout_resid = 0;
 
-	if (rq->next_rq) {
+	if (job->bidi_rq) {
 		unsigned int rsp_len = job->reply_payload.payload_len;
 
 		if (WARN_ON(job->reply_payload_rcv_len > rsp_len))
@@ -111,6 +140,11 @@ static void bsg_transport_free_rq(struct request *rq)
 {
 	struct bsg_job *job = blk_mq_rq_to_pdu(rq);
 
+	if (job->bidi_rq) {
+		blk_rq_unmap_user(job->bidi_bio);
+		blk_put_request(job->bidi_rq);
+	}
+
 	kfree(job->request);
 }
 
@@ -200,7 +234,6 @@ static int bsg_map_buffer(struct bsg_buffer *buf, struct request *req)
  */
 static bool bsg_prepare_job(struct device *dev, struct request *req)
 {
-	struct request *rsp = req->next_rq;
 	struct bsg_job *job = blk_mq_rq_to_pdu(req);
 	int ret;
 
@@ -211,8 +244,8 @@ static bool bsg_prepare_job(struct device *dev, struct request *req)
 		if (ret)
 			goto failjob_rls_job;
 	}
-	if (rsp && rsp->bio) {
-		ret = bsg_map_buffer(&job->reply_payload, rsp);
+	if (job->bidi_rq) {
+		ret = bsg_map_buffer(&job->reply_payload, job->bidi_rq);
 		if (ret)
 			goto failjob_rls_rqst_payload;
 	}
@@ -369,7 +402,6 @@ struct request_queue *bsg_setup_queue(struct device *dev, const char *name,
 	}
 
 	q->queuedata = dev;
-	blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
 	blk_queue_rq_timeout(q, BLK_DEFAULT_SG_TIMEOUT);
 
 	ret = bsg_register_queue(q, dev, name, &bsg_transport_ops);
diff --git a/block/bsg.c b/block/bsg.c
index a799b0ace55c..f306853c6b08 100644
--- a/block/bsg.c
+++ b/block/bsg.c
@@ -74,6 +74,11 @@ static int bsg_scsi_fill_hdr(struct request *rq, struct sg_io_v4 *hdr,
 {
 	struct scsi_request *sreq = scsi_req(rq);
 
+	if (hdr->dout_xfer_len && hdr->din_xfer_len) {
+		pr_warn_once("BIDI support in bsg has been removed.\n");
+		return -EOPNOTSUPP;
+	}
+
 	sreq->cmd_len = hdr->request_len;
 	if (sreq->cmd_len > BLK_MAX_CDB) {
 		sreq->cmd = kzalloc(sreq->cmd_len, GFP_KERNEL);
@@ -114,14 +119,10 @@ static int bsg_scsi_complete_rq(struct request *rq, struct sg_io_v4 *hdr)
 			hdr->response_len = len;
 	}
 
-	if (rq->next_rq) {
-		hdr->dout_resid = sreq->resid_len;
-		hdr->din_resid = scsi_req(rq->next_rq)->resid_len;
-	} else if (rq_data_dir(rq) == READ) {
+	if (rq_data_dir(rq) == READ)
 		hdr->din_resid = sreq->resid_len;
-	} else {
+	else
 		hdr->dout_resid = sreq->resid_len;
-	}
 
 	return ret;
 }
@@ -140,8 +141,8 @@ static const struct bsg_ops bsg_scsi_ops = {
 
 static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 {
-	struct request *rq, *next_rq = NULL;
-	struct bio *bio, *bidi_bio = NULL;
+	struct request *rq;
+	struct bio *bio;
 	struct sg_io_v4 hdr;
 	int ret;
 
@@ -164,7 +165,7 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 
 	ret = q->bsg_dev.ops->fill_hdr(rq, &hdr, mode);
 	if (ret)
-		goto out;
+		return ret;
 
 	rq->timeout = msecs_to_jiffies(hdr.timeout);
 	if (!rq->timeout)
@@ -174,29 +175,6 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 	if (rq->timeout < BLK_MIN_SG_TIMEOUT)
 		rq->timeout = BLK_MIN_SG_TIMEOUT;
 
-	if (hdr.dout_xfer_len && hdr.din_xfer_len) {
-		if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) {
-			ret = -EOPNOTSUPP;
-			goto out;
-		}
-
-		pr_warn_once(
-			"BIDI support in bsg has been deprecated and might be removed. "
-			"Please report your use case to linux-scsi@vger.kernel.org\n");
-
-		next_rq = blk_get_request(q, REQ_OP_SCSI_IN, 0);
-		if (IS_ERR(next_rq)) {
-			ret = PTR_ERR(next_rq);
-			goto out;
-		}
-
-		rq->next_rq = next_rq;
-		ret = blk_rq_map_user(q, next_rq, NULL, uptr64(hdr.din_xferp),
-				       hdr.din_xfer_len, GFP_KERNEL);
-		if (ret)
-			goto out_free_nextrq;
-	}
-
 	if (hdr.dout_xfer_len) {
 		ret = blk_rq_map_user(q, rq, NULL, uptr64(hdr.dout_xferp),
 				hdr.dout_xfer_len, GFP_KERNEL);
@@ -206,38 +184,20 @@ static int bsg_sg_io(struct request_queue *q, fmode_t mode, void __user *uarg)
 	}
 
 	if (ret)
-		goto out_unmap_nextrq;
+		goto out_free_rq;
 
 	bio = rq->bio;
-	if (rq->next_rq)
-		bidi_bio = rq->next_rq->bio;
 
 	blk_execute_rq(q, NULL, rq, !(hdr.flags & BSG_FLAG_Q_AT_TAIL));
 	ret = rq->q->bsg_dev.ops->complete_rq(rq, &hdr);
-
-	if (rq->next_rq) {
-		blk_rq_unmap_user(bidi_bio);
-		blk_put_request(rq->next_rq);
-	}
-
 	blk_rq_unmap_user(bio);
+
+out_free_rq:
 	rq->q->bsg_dev.ops->free_rq(rq);
 	blk_put_request(rq);
-
-	if (copy_to_user(uarg, &hdr, sizeof(hdr)))
+	if (!ret && copy_to_user(uarg, &hdr, sizeof(hdr)))
 		return -EFAULT;
 	return ret;
-
-out_unmap_nextrq:
-	if (rq->next_rq)
-		blk_rq_unmap_user(rq->next_rq->bio);
-out_free_nextrq:
-	if (rq->next_rq)
-		blk_put_request(rq->next_rq);
-out:
-	q->bsg_dev.ops->free_rq(rq);
-	blk_put_request(rq);
-	return ret;
 }
 
 static struct bsg_device *bsg_alloc_device(void)
diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transport_sas.c
index 692b46937e52..60f1a81d2034 100644
--- a/drivers/scsi/scsi_transport_sas.c
+++ b/drivers/scsi/scsi_transport_sas.c
@@ -213,7 +213,6 @@ static int sas_bsg_initialize(struct Scsi_Host *shost, struct sas_rphy *rphy)
 		to_sas_host_attrs(shost)->q = q;
 	}
 
-	blk_queue_flag_set(QUEUE_FLAG_BIDI, q);
 	return 0;
 }
 
diff --git a/include/linux/bsg-lib.h b/include/linux/bsg-lib.h
index b356e0006731..7f14517a559b 100644
--- a/include/linux/bsg-lib.h
+++ b/include/linux/bsg-lib.h
@@ -69,6 +69,10 @@ struct bsg_job {
 	int result;
 	unsigned int reply_payload_rcv_len;
 
+	/* BIDI support */
+	struct request *bidi_rq;
+	struct bio *bidi_bio;
+
 	void *dd_data;		/* Used for driver-specific storage */
 };
 
-- 
2.20.1

[PATCH 5/8] scsi: remove bidirectional command support

[Christoph Hellwig]

No real need for bidi support once the OSD code is gone.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/cxgbi/libcxgbi.c      | 13 +++---
 drivers/scsi/iscsi_tcp.c           |  9 +----
 drivers/scsi/libiscsi.c            | 64 +++---------------------------
 drivers/scsi/libiscsi_tcp.c        |  8 ++--
 drivers/scsi/scsi_debug.c          | 51 +++++-------------------
 drivers/scsi/scsi_error.c          |  3 --
 drivers/scsi/scsi_lib.c            | 58 ++-------------------------
 drivers/scsi/virtio_scsi.c         | 14 ++-----
 drivers/target/loopback/tcm_loop.c | 15 -------
 drivers/usb/storage/uas.c          | 11 +----
 include/scsi/scsi_cmnd.h           | 19 +--------
 include/scsi/scsi_eh.h             |  1 -
 12 files changed, 35 insertions(+), 231 deletions(-)

diff --git a/drivers/scsi/cxgbi/libcxgbi.c b/drivers/scsi/cxgbi/libcxgbi.c
index 75f876409fb9..4466ae5c9a74 100644
--- a/drivers/scsi/cxgbi/libcxgbi.c
+++ b/drivers/scsi/cxgbi/libcxgbi.c
@@ -1211,7 +1211,7 @@ scmd_get_params(struct scsi_cmnd *sc, struct scatterlist **sgl,
 		unsigned int *sgcnt, unsigned int *dlen,
 		unsigned int prot)
 {
-	struct scsi_data_buffer *sdb = prot ? scsi_prot(sc) : scsi_out(sc);
+	struct scsi_data_buffer *sdb = prot ? scsi_prot(sc) : &sc->sdb;
 
 	*sgl = sdb->table.sgl;
 	*sgcnt = sdb->table.nents;
@@ -1427,8 +1427,7 @@ static void task_release_itt(struct iscsi_task *task, itt_t hdr_itt)
 	log_debug(1 << CXGBI_DBG_DDP,
 		  "cdev 0x%p, task 0x%p, release tag 0x%x.\n",
 		  cdev, task, tag);
-	if (sc &&
-	    (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE) &&
+	if (sc && sc->sc_data_direction == DMA_FROM_DEVICE &&
 	    cxgbi_ppm_is_ddp_tag(ppm, tag)) {
 		struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);
 		struct cxgbi_task_tag_info *ttinfo = &tdata->ttinfo;
@@ -1460,9 +1459,7 @@ static int task_reserve_itt(struct iscsi_task *task, itt_t *hdr_itt)
 	u32 tag = 0;
 	int err = -EINVAL;
 
-	if (sc &&
-	    (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_FROM_DEVICE)
-	) {
+	if (sc && sc->sc_data_direction == DMA_FROM_DEVICE) {
 		struct cxgbi_task_data *tdata = iscsi_task_cxgbi_data(task);
 		struct cxgbi_task_tag_info *ttinfo = &tdata->ttinfo;
 
@@ -1896,7 +1893,7 @@ int cxgbi_conn_alloc_pdu(struct iscsi_task *task, u8 opcode)
 	if (SKB_MAX_HEAD(cdev->skb_tx_rsvd) > (512 * MAX_SKB_FRAGS) &&
 	    (opcode == ISCSI_OP_SCSI_DATA_OUT ||
 	     (opcode == ISCSI_OP_SCSI_CMD &&
-	      (scsi_bidi_cmnd(sc) || sc->sc_data_direction == DMA_TO_DEVICE))))
+	      sc->sc_data_direction == DMA_TO_DEVICE)))
 		/* data could goes into skb head */
 		headroom += min_t(unsigned int,
 				SKB_MAX_HEAD(cdev->skb_tx_rsvd),
@@ -1971,7 +1968,7 @@ int cxgbi_conn_init_pdu(struct iscsi_task *task, unsigned int offset,
 		return 0;
 
 	if (task->sc) {
-		struct scsi_data_buffer *sdb = scsi_out(task->sc);
+		struct scsi_data_buffer *sdb = &task->sc->sdb;
 		struct scatterlist *sg = NULL;
 		int err;
 
diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index cae6368ebb98..ed3debce2819 100644
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -518,7 +518,7 @@ static int iscsi_sw_tcp_pdu_init(struct iscsi_task *task,
 	if (!task->sc)
 		iscsi_sw_tcp_send_linear_data_prep(conn, task->data, count);
 	else {
-		struct scsi_data_buffer *sdb = scsi_out(task->sc);
+		struct scsi_data_buffer *sdb = &task->sc->sdb;
 
 		err = iscsi_sw_tcp_send_data_prep(conn, sdb->table.sgl,
 						  sdb->table.nents, offset,
@@ -952,12 +952,6 @@ static umode_t iscsi_sw_tcp_attr_is_visible(int param_type, int param)
 	return 0;
 }
 
-static int iscsi_sw_tcp_slave_alloc(struct scsi_device *sdev)
-{
-	blk_queue_flag_set(QUEUE_FLAG_BIDI, sdev->request_queue);
-	return 0;
-}
-
 static int iscsi_sw_tcp_slave_configure(struct scsi_device *sdev)
 {
 	struct iscsi_sw_tcp_host *tcp_sw_host = iscsi_host_priv(sdev->host);
@@ -985,7 +979,6 @@ static struct scsi_host_template iscsi_sw_tcp_sht = {
 	.eh_device_reset_handler= iscsi_eh_device_reset,
 	.eh_target_reset_handler = iscsi_eh_recover_target,
 	.dma_boundary		= PAGE_SIZE - 1,
-	.slave_alloc            = iscsi_sw_tcp_slave_alloc,
 	.slave_configure        = iscsi_sw_tcp_slave_configure,
 	.target_alloc		= iscsi_target_alloc,
 	.proc_name		= "iscsi_tcp",
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index b8d325ce8754..bca3a8636c27 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -228,32 +228,6 @@ static int iscsi_prep_ecdb_ahs(struct iscsi_task *task)
 	return 0;
 }
 
-static int iscsi_prep_bidi_ahs(struct iscsi_task *task)
-{
-	struct scsi_cmnd *sc = task->sc;
-	struct iscsi_rlength_ahdr *rlen_ahdr;
-	int rc;
-
-	rlen_ahdr = iscsi_next_hdr(task);
-	rc = iscsi_add_hdr(task, sizeof(*rlen_ahdr));
-	if (rc)
-		return rc;
-
-	rlen_ahdr->ahslength =
-		cpu_to_be16(sizeof(rlen_ahdr->read_length) +
-						  sizeof(rlen_ahdr->reserved));
-	rlen_ahdr->ahstype = ISCSI_AHSTYPE_RLENGTH;
-	rlen_ahdr->reserved = 0;
-	rlen_ahdr->read_length = cpu_to_be32(scsi_in(sc)->length);
-
-	ISCSI_DBG_SESSION(task->conn->session,
-			  "bidi-in rlen_ahdr->read_length(%d) "
-		          "rlen_ahdr->ahslength(%d)\n",
-		          be32_to_cpu(rlen_ahdr->read_length),
-		          be16_to_cpu(rlen_ahdr->ahslength));
-	return 0;
-}
-
 /**
  * iscsi_check_tmf_restrictions - check if a task is affected by TMF
  * @task: iscsi task
@@ -392,13 +366,6 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
 	memcpy(hdr->cdb, sc->cmnd, cmd_len);
 
 	task->imm_count = 0;
-	if (scsi_bidi_cmnd(sc)) {
-		hdr->flags |= ISCSI_FLAG_CMD_READ;
-		rc = iscsi_prep_bidi_ahs(task);
-		if (rc)
-			return rc;
-	}
-
 	if (scsi_get_prot_op(sc) != SCSI_PROT_NORMAL)
 		task->protected = true;
 
@@ -473,12 +440,10 @@ static int iscsi_prep_scsi_cmd_pdu(struct iscsi_task *task)
 
 	conn->scsicmd_pdus_cnt++;
 	ISCSI_DBG_SESSION(session, "iscsi prep [%s cid %d sc %p cdb 0x%x "
-			  "itt 0x%x len %d bidi_len %d cmdsn %d win %d]\n",
-			  scsi_bidi_cmnd(sc) ? "bidirectional" :
+			  "itt 0x%x len %d cmdsn %d win %d]\n",
 			  sc->sc_data_direction == DMA_TO_DEVICE ?
 			  "write" : "read", conn->id, sc, sc->cmnd[0],
 			  task->itt, transfer_length,
-			  scsi_bidi_cmnd(sc) ? scsi_in(sc)->length : 0,
 			  session->cmdsn,
 			  session->max_cmdsn - session->exp_cmdsn + 1);
 	return 0;
@@ -647,12 +612,7 @@ static void fail_scsi_task(struct iscsi_task *task, int err)
 		state = ISCSI_TASK_ABRT_TMF;
 
 	sc->result = err << 16;
-	if (!scsi_bidi_cmnd(sc))
-		scsi_set_resid(sc, scsi_bufflen(sc));
-	else {
-		scsi_out(sc)->resid = scsi_out(sc)->length;
-		scsi_in(sc)->resid = scsi_in(sc)->length;
-	}
+	scsi_set_resid(sc, scsi_bufflen(sc));
 
 	/* regular RX path uses back_lock */
 	spin_lock_bh(&conn->session->back_lock);
@@ -907,14 +867,7 @@ static void iscsi_scsi_cmd_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 
 	if (rhdr->flags & (ISCSI_FLAG_CMD_BIDI_UNDERFLOW |
 			   ISCSI_FLAG_CMD_BIDI_OVERFLOW)) {
-		int res_count = be32_to_cpu(rhdr->bi_residual_count);
-
-		if (scsi_bidi_cmnd(sc) && res_count > 0 &&
-				(rhdr->flags & ISCSI_FLAG_CMD_BIDI_OVERFLOW ||
-				 res_count <= scsi_in(sc)->length))
-			scsi_in(sc)->resid = res_count;
-		else
-			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
+		sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
 	}
 
 	if (rhdr->flags & (ISCSI_FLAG_CMD_UNDERFLOW |
@@ -961,8 +914,8 @@ iscsi_data_in_rsp(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
 
 		if (res_count > 0 &&
 		    (rhdr->flags & ISCSI_FLAG_CMD_OVERFLOW ||
-		     res_count <= scsi_in(sc)->length))
-			scsi_in(sc)->resid = res_count;
+		     res_count <= sc->sdb.length))
+			sc->sdb.resid = res_count;
 		else
 			sc->result = (DID_BAD_TARGET << 16) | rhdr->cmd_status;
 	}
@@ -1804,12 +1757,7 @@ int iscsi_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *sc)
 	spin_unlock_bh(&session->frwd_lock);
 	ISCSI_DBG_SESSION(session, "iscsi: cmd 0x%x is not queued (%d)\n",
 			  sc->cmnd[0], reason);
-	if (!scsi_bidi_cmnd(sc))
-		scsi_set_resid(sc, scsi_bufflen(sc));
-	else {
-		scsi_out(sc)->resid = scsi_out(sc)->length;
-		scsi_in(sc)->resid = scsi_in(sc)->length;
-	}
+	scsi_set_resid(sc, scsi_bufflen(sc));
 	sc->scsi_done(sc);
 	return 0;
 }
diff --git a/drivers/scsi/libiscsi_tcp.c b/drivers/scsi/libiscsi_tcp.c
index 8a6b1b3f8277..9923e9e3b884 100644
--- a/drivers/scsi/libiscsi_tcp.c
+++ b/drivers/scsi/libiscsi_tcp.c
@@ -495,7 +495,7 @@ static int iscsi_tcp_data_in(struct iscsi_conn *conn, struct iscsi_task *task)
 	struct iscsi_tcp_task *tcp_task = task->dd_data;
 	struct iscsi_data_rsp *rhdr = (struct iscsi_data_rsp *)tcp_conn->in.hdr;
 	int datasn = be32_to_cpu(rhdr->datasn);
-	unsigned total_in_length = scsi_in(task->sc)->length;
+	unsigned total_in_length = task->sc->sdb.length;
 
 	/*
 	 * lib iscsi will update this in the completion handling if there
@@ -580,11 +580,11 @@ static int iscsi_tcp_r2t_rsp(struct iscsi_conn *conn, struct iscsi_task *task)
 			      data_length, session->max_burst);
 
 	data_offset = be32_to_cpu(rhdr->data_offset);
-	if (data_offset + data_length > scsi_out(task->sc)->length) {
+	if (data_offset + data_length > task->sc->sdb.length) {
 		iscsi_conn_printk(KERN_ERR, conn,
 				  "invalid R2T with data len %u at offset %u "
 				  "and total length %d\n", data_length,
-				  data_offset, scsi_out(task->sc)->length);
+				  data_offset, task->sc->sdb.length);
 		return ISCSI_ERR_DATALEN;
 	}
 
@@ -696,7 +696,7 @@ iscsi_tcp_hdr_dissect(struct iscsi_conn *conn, struct iscsi_hdr *hdr)
 		if (tcp_conn->in.datalen) {
 			struct iscsi_tcp_task *tcp_task = task->dd_data;
 			struct ahash_request *rx_hash = NULL;
-			struct scsi_data_buffer *sdb = scsi_in(task->sc);
+			struct scsi_data_buffer *sdb = &task->sc->sdb;
 
 			/*
 			 * Setup copy of Data-In into the struct scsi_cmnd
diff --git a/drivers/scsi/scsi_debug.c b/drivers/scsi/scsi_debug.c
index 661512bec3ac..cb8b5dfe1fa9 100644
--- a/drivers/scsi/scsi_debug.c
+++ b/drivers/scsi/scsi_debug.c
@@ -430,7 +430,6 @@ static int resp_rsup_opcodes(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_rsup_tmfs(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_write_same_10(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_write_same_16(struct scsi_cmnd *, struct sdebug_dev_info *);
-static int resp_xdwriteread_10(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_comp_write(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_write_buffer(struct scsi_cmnd *, struct sdebug_dev_info *);
 static int resp_sync_cache(struct scsi_cmnd *, struct sdebug_dev_info *);
@@ -600,9 +599,6 @@ static const struct opcode_info_t opcode_info_arr[SDEB_I_LAST_ELEMENT + 1] = {
 	{0, 0x42, 0, F_D_OUT | FF_MEDIA_IO, resp_unmap, NULL, /* UNMAP */
 	    {10,  0x1, 0, 0, 0, 0, 0x3f, 0xff, 0xff, 0xc7, 0, 0, 0, 0, 0, 0} },
 /* 25 */
-	{0, 0x53, 0, F_D_IN | F_D_OUT | FF_MEDIA_IO, resp_xdwriteread_10,
-	    NULL, {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0x3f, 0xff, 0xff, 0xc7,
-		   0, 0, 0, 0, 0, 0} },		/* XDWRITEREAD(10) */
 	{0, 0x3b, 0, F_D_OUT_MAYBE, resp_write_buffer, NULL,
 	    {10,  0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xc7, 0, 0,
 	     0, 0, 0, 0} },			/* WRITE_BUFFER */
@@ -1010,11 +1006,11 @@ static int fill_from_dev_buffer(struct scsi_cmnd *scp, unsigned char *arr,
 				int arr_len)
 {
 	int act_len;
-	struct scsi_data_buffer *sdb = scsi_in(scp);
+	struct scsi_data_buffer *sdb = &scp->sdb;
 
 	if (!sdb->length)
 		return 0;
-	if (!(scsi_bidi_cmnd(scp) || scp->sc_data_direction == DMA_FROM_DEVICE))
+	if (scp->sc_data_direction != DMA_FROM_DEVICE)
 		return DID_ERROR << 16;
 
 	act_len = sg_copy_from_buffer(sdb->table.sgl, sdb->table.nents,
@@ -1033,12 +1029,12 @@ static int p_fill_from_dev_buffer(struct scsi_cmnd *scp, const void *arr,
 				  int arr_len, unsigned int off_dst)
 {
 	int act_len, n;
-	struct scsi_data_buffer *sdb = scsi_in(scp);
+	struct scsi_data_buffer *sdb = &scp->sdb;
 	off_t skip = off_dst;
 
 	if (sdb->length <= off_dst)
 		return 0;
-	if (!(scsi_bidi_cmnd(scp) || scp->sc_data_direction == DMA_FROM_DEVICE))
+	if (scp->sc_data_direction != DMA_FROM_DEVICE)
 		return DID_ERROR << 16;
 
 	act_len = sg_pcopy_from_buffer(sdb->table.sgl, sdb->table.nents,
@@ -1058,7 +1054,7 @@ static int fetch_to_dev_buffer(struct scsi_cmnd *scp, unsigned char *arr,
 {
 	if (!scsi_bufflen(scp))
 		return 0;
-	if (!(scsi_bidi_cmnd(scp) || scp->sc_data_direction == DMA_TO_DEVICE))
+	if (scp->sc_data_direction != DMA_TO_DEVICE)
 		return -1;
 
 	return scsi_sg_copy_to_buffer(scp, arr, arr_len);
@@ -2477,21 +2473,19 @@ static int do_device_access(struct scsi_cmnd *scmd, u32 sg_skip, u64 lba,
 {
 	int ret;
 	u64 block, rest = 0;
-	struct scsi_data_buffer *sdb;
+	struct scsi_data_buffer *sdb = &scmd->sdb;
 	enum dma_data_direction dir;
 
 	if (do_write) {
-		sdb = scsi_out(scmd);
 		dir = DMA_TO_DEVICE;
 		write_since_sync = true;
 	} else {
-		sdb = scsi_in(scmd);
 		dir = DMA_FROM_DEVICE;
 	}
 
 	if (!sdb->length)
 		return 0;
-	if (!(scsi_bidi_cmnd(scmd) || scmd->sc_data_direction == dir))
+	if (scmd->sc_data_direction != dir)
 		return -1;
 
 	block = do_div(lba, sdebug_store_sectors);
@@ -2774,7 +2768,7 @@ static int resp_read_dt0(struct scsi_cmnd *scp, struct sdebug_dev_info *devip)
 	if (unlikely(ret == -1))
 		return DID_ERROR << 16;
 
-	scsi_in(scp)->resid = scsi_bufflen(scp) - ret;
+	scp->sdb.resid = scsi_bufflen(scp) - ret;
 
 	if (unlikely(sqcp)) {
 		if (sqcp->inj_recovered) {
@@ -3724,7 +3718,7 @@ static int resp_xdwriteread(struct scsi_cmnd *scp, unsigned long long lba,
 	int j;
 	unsigned char *kaddr, *buf;
 	unsigned int offset;
-	struct scsi_data_buffer *sdb = scsi_in(scp);
+	struct scsi_data_buffer *sdb = &scp->sdb;
 	struct sg_mapping_iter miter;
 
 	/* better not to use temporary buffer. */
@@ -3754,32 +3748,6 @@ static int resp_xdwriteread(struct scsi_cmnd *scp, unsigned long long lba,
 	return 0;
 }
 
-static int resp_xdwriteread_10(struct scsi_cmnd *scp,
-			       struct sdebug_dev_info *devip)
-{
-	u8 *cmd = scp->cmnd;
-	u64 lba;
-	u32 num;
-	int errsts;
-
-	if (!scsi_bidi_cmnd(scp)) {
-		mk_sense_buffer(scp, ILLEGAL_REQUEST, INSUFF_RES_ASC,
-				INSUFF_RES_ASCQ);
-		return check_condition_result;
-	}
-	errsts = resp_read_dt0(scp, devip);
-	if (errsts)
-		return errsts;
-	if (!(cmd[1] & 0x4)) {		/* DISABLE_WRITE is not set */
-		errsts = resp_write_dt0(scp, devip);
-		if (errsts)
-			return errsts;
-	}
-	lba = get_unaligned_be32(cmd + 2);
-	num = get_unaligned_be16(cmd + 7);
-	return resp_xdwriteread(scp, lba, num, devip);
-}
-
 static struct sdebug_queue *get_queue(struct scsi_cmnd *cmnd)
 {
 	u32 tag = blk_mq_unique_tag(cmnd->request);
@@ -3953,7 +3921,6 @@ static int scsi_debug_slave_alloc(struct scsi_device *sdp)
 	if (sdebug_verbose)
 		pr_info("slave_alloc <%u %u %u %llu>\n",
 		       sdp->host->host_no, sdp->channel, sdp->id, sdp->lun);
-	blk_queue_flag_set(QUEUE_FLAG_BIDI, sdp->request_queue);
 	return 0;
 }
 
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 16eef068e9e9..1b8378f36139 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -965,7 +965,6 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 	ses->cmnd = scmd->cmnd;
 	ses->data_direction = scmd->sc_data_direction;
 	ses->sdb = scmd->sdb;
-	ses->next_rq = scmd->request->next_rq;
 	ses->result = scmd->result;
 	ses->underflow = scmd->underflow;
 	ses->prot_op = scmd->prot_op;
@@ -976,7 +975,6 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 	scmd->cmnd = ses->eh_cmnd;
 	memset(scmd->cmnd, 0, BLK_MAX_CDB);
 	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
-	scmd->request->next_rq = NULL;
 	scmd->result = 0;
 
 	if (sense_bytes) {
@@ -1029,7 +1027,6 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 	scmd->cmnd = ses->cmnd;
 	scmd->sc_data_direction = ses->data_direction;
 	scmd->sdb = ses->sdb;
-	scmd->request->next_rq = ses->next_rq;
 	scmd->result = ses->result;
 	scmd->underflow = ses->underflow;
 	scmd->prot_op = ses->prot_op;
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 00cd365fb7d2..6fd1d8d83f07 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -560,11 +560,6 @@ static void scsi_mq_free_sgtables(struct scsi_cmnd *cmd)
 
 	if (cmd->sdb.table.nents)
 		sg_free_table_chained(&cmd->sdb.table, true);
-	if (cmd->request->next_rq) {
-		sdb = cmd->request->next_rq->special;
-		if (sdb)
-			sg_free_table_chained(&sdb->table, true);
-	}
 	if (scsi_prot_sg_count(cmd))
 		sg_free_table_chained(&cmd->prot_sdb->table, true);
 }
@@ -578,7 +573,7 @@ static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
 
 /* Returns false when no more bytes to process, true if there are more */
 static bool scsi_end_request(struct request *req, blk_status_t error,
-		unsigned int bytes, unsigned int bidi_bytes)
+		unsigned int bytes)
 {
 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
 	struct scsi_device *sdev = cmd->device;
@@ -587,11 +582,6 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
 	if (blk_update_request(req, error, bytes))
 		return true;
 
-	/* Bidi request must be completed as a whole */
-	if (unlikely(bidi_bytes) &&
-	    blk_update_request(req->next_rq, error, bidi_bytes))
-		return true;
-
 	if (blk_queue_add_random(q))
 		add_disk_randomness(req->rq_disk);
 
@@ -816,7 +806,7 @@ static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
 				scsi_print_command(cmd);
 			}
 		}
-		if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req), 0))
+		if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
 			return;
 		/*FALLTHRU*/
 	case ACTION_REPREP:
@@ -951,29 +941,6 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
 		 */
 		scsi_req(req)->result = cmd->result;
 		scsi_req(req)->resid_len = scsi_get_resid(cmd);
-
-		if (unlikely(scsi_bidi_cmnd(cmd))) {
-			/*
-			 * Bidi commands Must be complete as a whole,
-			 * both sides at once.
-			 */
-			scsi_req(req->next_rq)->resid_len = scsi_in(cmd)->resid;
-			if (scsi_end_request(req, BLK_STS_OK, blk_rq_bytes(req),
-					blk_rq_bytes(req->next_rq)))
-				WARN_ONCE(true,
-					  "Bidi command with remaining bytes");
-			return;
-		}
-	}
-
-	/* no bidi support yet, other than in pass-through */
-	if (unlikely(blk_bidi_rq(req))) {
-		WARN_ONCE(true, "Only support bidi command in passthrough");
-		scmd_printk(KERN_ERR, cmd, "Killing bidi command\n");
-		if (scsi_end_request(req, BLK_STS_IOERR, blk_rq_bytes(req),
-				     blk_rq_bytes(req->next_rq)))
-			WARN_ONCE(true, "Bidi command with remaining bytes");
-		return;
 	}
 
 	/*
@@ -990,13 +957,13 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
 	 * to retry code. Fast path should return in this block.
 	 */
 	if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
-		if (likely(!scsi_end_request(req, blk_stat, good_bytes, 0)))
+		if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
 			return; /* no bytes remaining */
 	}
 
 	/* Kill remainder if no retries. */
 	if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
-		if (scsi_end_request(req, blk_stat, blk_rq_bytes(req), 0))
+		if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
 			WARN_ONCE(true,
 			    "Bytes remaining after failed, no-retry command");
 		return;
@@ -1058,12 +1025,6 @@ blk_status_t scsi_init_io(struct scsi_cmnd *cmd)
 	if (ret)
 		return ret;
 
-	if (blk_bidi_rq(rq)) {
-		ret = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
-		if (ret)
-			goto out_free_sgtables;
-	}
-
 	if (blk_integrity_rq(rq)) {
 		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
 		int ivecs, count;
@@ -1624,17 +1585,6 @@ static blk_status_t scsi_mq_prep_fn(struct request *req)
 			(struct scatterlist *)(cmd->prot_sdb + 1);
 	}
 
-	if (blk_bidi_rq(req)) {
-		struct request *next_rq = req->next_rq;
-		struct scsi_data_buffer *bidi_sdb = blk_mq_rq_to_pdu(next_rq);
-
-		memset(bidi_sdb, 0, sizeof(struct scsi_data_buffer));
-		bidi_sdb->table.sgl =
-			(struct scatterlist *)(bidi_sdb + 1);
-
-		next_rq->special = bidi_sdb;
-	}
-
 	blk_mq_start_request(req);
 
 	return scsi_setup_cmnd(sdev, req);
diff --git a/drivers/scsi/virtio_scsi.c b/drivers/scsi/virtio_scsi.c
index 772b976e4ee4..1a6f150cd2d8 100644
--- a/drivers/scsi/virtio_scsi.c
+++ b/drivers/scsi/virtio_scsi.c
@@ -100,16 +100,8 @@ static inline struct Scsi_Host *virtio_scsi_host(struct virtio_device *vdev)
 
 static void virtscsi_compute_resid(struct scsi_cmnd *sc, u32 resid)
 {
-	if (!resid)
-		return;
-
-	if (!scsi_bidi_cmnd(sc)) {
+	if (resid)
 		scsi_set_resid(sc, resid);
-		return;
-	}
-
-	scsi_in(sc)->resid = min(resid, scsi_in(sc)->length);
-	scsi_out(sc)->resid = resid - scsi_in(sc)->resid;
 }
 
 /**
@@ -403,9 +395,9 @@ static int virtscsi_add_cmd(struct virtqueue *vq,
 
 	if (sc && sc->sc_data_direction != DMA_NONE) {
 		if (sc->sc_data_direction != DMA_FROM_DEVICE)
-			out = &scsi_out(sc)->table;
+			out = &sc->sdb.table;
 		if (sc->sc_data_direction != DMA_TO_DEVICE)
-			in = &scsi_in(sc)->table;
+			in = &sc->sdb.table;
 	}
 
 	/* Request header.  */
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index 7bd7c0c0db6f..757d4a8eba32 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -128,14 +128,6 @@ static void tcm_loop_submission_work(struct work_struct *work)
 		set_host_byte(sc, DID_ERROR);
 		goto out_done;
 	}
-	if (scsi_bidi_cmnd(sc)) {
-		struct scsi_data_buffer *sdb = scsi_in(sc);
-
-		sgl_bidi = sdb->table.sgl;
-		sgl_bidi_count = sdb->table.nents;
-		se_cmd->se_cmd_flags |= SCF_BIDI;
-
-	}
 
 	transfer_length = scsi_transfer_length(sc);
 	if (!scsi_prot_sg_count(sc) &&
@@ -304,12 +296,6 @@ static int tcm_loop_target_reset(struct scsi_cmnd *sc)
 	return FAILED;
 }
 
-static int tcm_loop_slave_alloc(struct scsi_device *sd)
-{
-	blk_queue_flag_set(QUEUE_FLAG_BIDI, sd->request_queue);
-	return 0;
-}
-
 static struct scsi_host_template tcm_loop_driver_template = {
 	.show_info		= tcm_loop_show_info,
 	.proc_name		= "tcm_loopback",
@@ -325,7 +311,6 @@ static struct scsi_host_template tcm_loop_driver_template = {
 	.cmd_per_lun		= 1024,
 	.max_sectors		= 0xFFFF,
 	.dma_boundary		= PAGE_SIZE - 1,
-	.slave_alloc		= tcm_loop_slave_alloc,
 	.module			= THIS_MODULE,
 	.track_queue_depth	= 1,
 };
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 36742e8e7edc..95f2142093d5 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -368,25 +368,19 @@ static void uas_data_cmplt(struct urb *urb)
 	struct scsi_cmnd *cmnd = urb->context;
 	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 	struct uas_dev_info *devinfo = (void *)cmnd->device->hostdata;
-	struct scsi_data_buffer *sdb = NULL;
+	struct scsi_data_buffer *sdb = &cmnd->sdb;
 	unsigned long flags;
 	int status = urb->status;
 
 	spin_lock_irqsave(&devinfo->lock, flags);
 
 	if (cmdinfo->data_in_urb == urb) {
-		sdb = scsi_in(cmnd);
 		cmdinfo->state &= ~DATA_IN_URB_INFLIGHT;
 		cmdinfo->data_in_urb = NULL;
 	} else if (cmdinfo->data_out_urb == urb) {
-		sdb = scsi_out(cmnd);
 		cmdinfo->state &= ~DATA_OUT_URB_INFLIGHT;
 		cmdinfo->data_out_urb = NULL;
 	}
-	if (sdb == NULL) {
-		WARN_ON_ONCE(1);
-		goto out;
-	}
 
 	if (devinfo->resetting)
 		goto out;
@@ -426,8 +420,7 @@ static struct urb *uas_alloc_data_urb(struct uas_dev_info *devinfo, gfp_t gfp,
 	struct usb_device *udev = devinfo->udev;
 	struct uas_cmd_info *cmdinfo = (void *)&cmnd->SCp;
 	struct urb *urb = usb_alloc_urb(0, gfp);
-	struct scsi_data_buffer *sdb = (dir == DMA_FROM_DEVICE)
-		? scsi_in(cmnd) : scsi_out(cmnd);
+	struct scsi_data_buffer *sdb = &cmnd->sdb;
 	unsigned int pipe = (dir == DMA_FROM_DEVICE)
 		? devinfo->data_in_pipe : devinfo->data_out_pipe;
 
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index d85e6befa26b..af6ae3e1eba6 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -213,23 +213,6 @@ static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 #define scsi_for_each_sg(cmd, sg, nseg, __i)			\
 	for_each_sg(scsi_sglist(cmd), sg, nseg, __i)
 
-static inline int scsi_bidi_cmnd(struct scsi_cmnd *cmd)
-{
-	return blk_bidi_rq(cmd->request) &&
-		(cmd->request->next_rq->special != NULL);
-}
-
-static inline struct scsi_data_buffer *scsi_in(struct scsi_cmnd *cmd)
-{
-	return scsi_bidi_cmnd(cmd) ?
-		cmd->request->next_rq->special : &cmd->sdb;
-}
-
-static inline struct scsi_data_buffer *scsi_out(struct scsi_cmnd *cmd)
-{
-	return &cmd->sdb;
-}
-
 static inline int scsi_sg_copy_from_buffer(struct scsi_cmnd *cmd,
 					   void *buf, int buflen)
 {
@@ -351,7 +334,7 @@ static inline void set_driver_byte(struct scsi_cmnd *cmd, char status)
 
 static inline unsigned scsi_transfer_length(struct scsi_cmnd *scmd)
 {
-	unsigned int xfer_len = scsi_out(scmd)->length;
+	unsigned int xfer_len = scmd->sdb.length;
 	unsigned int prot_interval = scsi_prot_interval(scmd);
 
 	if (scmd->prot_flags & SCSI_PROT_TRANSFER_PI)
diff --git a/include/scsi/scsi_eh.h b/include/scsi/scsi_eh.h
index 2b7e227960e1..3810b340551c 100644
--- a/include/scsi/scsi_eh.h
+++ b/include/scsi/scsi_eh.h
@@ -39,7 +39,6 @@ struct scsi_eh_save {
 	unsigned char prot_op;
 	unsigned char *cmnd;
 	struct scsi_data_buffer sdb;
-	struct request *next_rq;
 	/* new command support */
 	unsigned char eh_cmnd[BLK_MAX_CDB];
 	struct scatterlist sense_sgl;
-- 
2.20.1

[PATCH 6/8] scsi: stop setting up request->special

[Christoph Hellwig]

No more need in a blk-mq world where the scsi command and request
are allocated together.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/scsi/qedf/qedf_io.c | 6 ------
 drivers/scsi/qedi/qedi_fw.c | 7 -------
 drivers/scsi/scsi_lib.c     | 3 ---
 drivers/scsi/sr.c           | 1 -
 4 files changed, 17 deletions(-)

diff --git a/drivers/scsi/qedf/qedf_io.c b/drivers/scsi/qedf/qedf_io.c
index 6bbc38b1b465..6ca583bdde23 100644
--- a/drivers/scsi/qedf/qedf_io.c
+++ b/drivers/scsi/qedf/qedf_io.c
@@ -1128,12 +1128,6 @@ void qedf_scsi_completion(struct qedf_ctx *qedf, struct fcoe_cqe *cqe,
 		return;
 	}
 
-	if (!sc_cmd->request->special) {
-		QEDF_WARN(&(qedf->dbg_ctx), "request->special is NULL so "
-		    "request not valid, sc_cmd=%p.\n", sc_cmd);
-		return;
-	}
-
 	if (!sc_cmd->request->q) {
 		QEDF_WARN(&(qedf->dbg_ctx), "request->q is NULL so request "
 		   "is not valid, sc_cmd=%p.\n", sc_cmd);
diff --git a/drivers/scsi/qedi/qedi_fw.c b/drivers/scsi/qedi/qedi_fw.c
index 25d763ae5d5a..e2a995a6e8e7 100644
--- a/drivers/scsi/qedi/qedi_fw.c
+++ b/drivers/scsi/qedi/qedi_fw.c
@@ -616,13 +616,6 @@ static void qedi_scsi_completion(struct qedi_ctx *qedi,
 		goto error;
 	}
 
-	if (!sc_cmd->request->special) {
-		QEDI_WARN(&qedi->dbg_ctx,
-			  "request->special is NULL so request not valid, sc_cmd=%p.\n",
-			  sc_cmd);
-		goto error;
-	}
-
 	if (!sc_cmd->request->q) {
 		QEDI_WARN(&qedi->dbg_ctx,
 			  "request->q is NULL so request is not valid, sc_cmd=%p.\n",
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 6fd1d8d83f07..7e256b384a99 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1568,10 +1568,7 @@ static blk_status_t scsi_mq_prep_fn(struct request *req)
 
 	scsi_init_command(sdev, cmd);
 
-	req->special = cmd;
-
 	cmd->request = req;
-
 	cmd->tag = req->tag;
 	cmd->prot_op = SCSI_PROT_NORMAL;
 
diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c
index 38ddbbfe5f3c..039c27c2d7b3 100644
--- a/drivers/scsi/sr.c
+++ b/drivers/scsi/sr.c
@@ -394,7 +394,6 @@ static blk_status_t sr_init_command(struct scsi_cmnd *SCpnt)
 	ret = scsi_init_io(SCpnt);
 	if (ret != BLK_STS_OK)
 		goto out;
-	WARN_ON_ONCE(SCpnt != rq->special);
 	cd = scsi_cd(rq->rq_disk);
 
 	/* from here on until we're complete, any goto out
-- 
2.20.1

[PATCH 7/8] block: remove req->special

[Christoph Hellwig]

No users left.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-mq.c         | 1 -
 include/linux/blkdev.h | 2 --
 2 files changed, 3 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 3ba37b9e15e9..502cbf964a3b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -331,7 +331,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 #if defined(CONFIG_BLK_DEV_INTEGRITY)
 	rq->nr_integrity_segments = 0;
 #endif
-	rq->special = NULL;
 	/* tag was already set */
 	rq->extra_len = 0;
 	WRITE_ONCE(rq->deadline, 0);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 338604dff7d0..fd1450d53f1c 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -216,8 +216,6 @@ struct request {
 	unsigned short write_hint;
 	unsigned short ioprio;
 
-	void *special;		/* opaque pointer available for LLD use */
-
 	unsigned int extra_len;	/* length of alignment and padding */
 
 	enum mq_rq_state state;
-- 
2.20.1

[PATCH 8/8] block: remove bidi support

[Christoph Hellwig]

Unused now, and another field in struct request bites the dust.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-mq-debugfs.c | 1 -
 block/blk-mq.c         | 3 ---
 include/linux/blkdev.h | 6 ------
 3 files changed, 10 deletions(-)

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 90d68760af08..ac832547160a 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -115,7 +115,6 @@ static int queue_pm_only_show(void *data, struct seq_file *m)
 static const char *const blk_queue_flag_name[] = {
 	QUEUE_FLAG_NAME(STOPPED),
 	QUEUE_FLAG_NAME(DYING),
-	QUEUE_FLAG_NAME(BIDI),
 	QUEUE_FLAG_NAME(NOMERGES),
 	QUEUE_FLAG_NAME(SAME_COMP),
 	QUEUE_FLAG_NAME(FAIL_IO),
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 502cbf964a3b..820d131a6893 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -339,7 +339,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
 
 	rq->end_io = NULL;
 	rq->end_io_data = NULL;
-	rq->next_rq = NULL;
 
 	data->ctx->rq_dispatched[op_is_sync(op)]++;
 	refcount_set(&rq->ref, 1);
@@ -549,8 +548,6 @@ inline void __blk_mq_end_request(struct request *rq, blk_status_t error)
 		rq_qos_done(rq->q, rq);
 		rq->end_io(rq, error);
 	} else {
-		if (unlikely(blk_bidi_rq(rq)))
-			blk_mq_free_request(rq->next_rq);
 		blk_mq_free_request(rq);
 	}
 }
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index fd1450d53f1c..21beb456b97a 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -234,9 +234,6 @@ struct request {
 	 */
 	rq_end_io_fn *end_io;
 	void *end_io_data;
-
-	/* for bidi */
-	struct request *next_rq;
 };
 
 static inline bool blk_op_is_scsi(unsigned int op)
@@ -572,7 +569,6 @@ struct request_queue {
 
 #define QUEUE_FLAG_STOPPED	1	/* queue is stopped */
 #define QUEUE_FLAG_DYING	2	/* queue being torn down */
-#define QUEUE_FLAG_BIDI		4	/* queue supports bidi requests */
 #define QUEUE_FLAG_NOMERGES     5	/* disable merge attempts */
 #define QUEUE_FLAG_SAME_COMP	6	/* complete on same CPU-group */
 #define QUEUE_FLAG_FAIL_IO	7	/* fake timeout */
@@ -644,8 +640,6 @@ static inline bool blk_account_rq(struct request *rq)
 	return (rq->rq_flags & RQF_STARTED) && !blk_rq_is_passthrough(rq);
 }
 
-#define blk_bidi_rq(rq)		((rq)->next_rq != NULL)
-
 #define list_entry_rq(ptr)	list_entry((ptr), struct request, queuelist)
 
 #define rq_data_dir(rq)		(op_is_write(req_op(rq)) ? WRITE : READ)
-- 
2.20.1

Re: remove exofs, the T10 OSD code and block/scsi bidi support V4

[Jens Axboe]

On 2/1/19 12:55 AM, Christoph Hellwig wrote:
> The only real user of the T10 OSD protocol, the pNFS object layout
> driver never went to the point of having shipping products, and we
> removed it 1.5 years ago.  Exofs is just a simple example without
> real life users.
> 
> The code has been mostly unmaintained for years and is getting in the
> way of block / SCSI changes, and does not even work properly currently,
> so I think it's finally time to drop it.
> 
> Quote from Boaz:
> 
> "As I said then. It is used in Universities for studies and experiments.
> Every once in a while. I get an email with questions and reports.
> 
> But yes feel free to remove the all thing!!
> 
> I guess I can put it up on github. In a public tree.
> 
> Just that I will need to forward port it myself, til now you guys
> been doing this for me ;-)"
> 
> Now the last time this caused a bit of a stir, but still no actual users,
> not even for SG_IO passthrough commands.  So here we go again, this time
> including removing everything in the scsi and block layer supporting it,
> and thus shrinking struct request.

I'm fine with killing it. You can add my:

Reviewed-by: Jens Axboe <axboe@kernel.dk>

to the series.

-- 
Jens Axboe

Re: [PATCH 7/8] block: remove req->special

[Christoph Hellwig]

FYI, this needs the following fold, as Bart added another reference
to ->special past the branch point for my tree:

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 4fbb8310e268..a1e43e77ceef 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1171,8 +1171,6 @@ static blk_status_t sd_setup_read_write_cmnd(struct scsi_cmnd *cmd)
 	if (ret != BLK_STS_OK)
 		return ret;
 
-	WARN_ON_ONCE(cmd != rq->special);
-
 	if (!scsi_device_online(sdp) || sdp->changed) {
 		scmd_printk(KERN_ERR, cmd, "device offline or changed\n");
 		return BLK_STS_IOERR;

Re: remove exofs, the T10 OSD code and block/scsi bidi support V4

[Boaz Harrosh]

On 01/02/19 09:55, Christoph Hellwig wrote:
> The only real user of the T10 OSD protocol, the pNFS object layout
> driver never went to the point of having shipping products, and we
> removed it 1.5 years ago.  Exofs is just a simple example without
> real life users.
> 
> The code has been mostly unmaintained for years and is getting in the
> way of block / SCSI changes, 

For the 4th time: Which ?

> and does not even work properly currently,
> so I think it's finally time to drop it.
> 
> Quote from Boaz:
> 

Hello? anyone home?

Please resend without the below Quote!!!
Because yes I said that but I have also said the opposite. And I have clearly
stated in reaction to the last 3 resends. That I now oppose to the below statement.
And that you should please remove it.

Do your own text please. Don't drag me in the mud

> "As I said then. It is used in Universities for studies and experiments.
> Every once in a while. I get an email with questions and reports.
> 
> But yes feel free to remove the all thing!!
> 
> I guess I can put it up on github. In a public tree.
> 
> Just that I will need to forward port it myself, til now you guys
> been doing this for me ;-)"
> 
> Now the last time this caused a bit of a stir, but still no actual users,
> not even for SG_IO passthrough commands.  So here we go again, this time
> including removing everything in the scsi and block layer supporting it,
> and thus shrinking struct request.
> 

NAK-by: Boaz harrosh <ooo@electrozaur.com>
For what ever that means ...

Cheers
Boaz

Re: remove exofs, the T10 OSD code and block/scsi bidi support V4

[Martin K. Petersen]

Christoph,

> The only real user of the T10 OSD protocol, the pNFS object layout
> driver never went to the point of having shipping products, and we
> removed it 1.5 years ago.  Exofs is just a simple example without real
> life users.
>
> The code has been mostly unmaintained for years and is getting in the
> way of block / SCSI changes, and does not even work properly currently,
> so I think it's finally time to drop it.

Applied to 5.1/scsi-queue. Thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: remove exofs, the T10 OSD code and block/scsi bidi support V4

[Christoph Hellwig]

On Mon, Feb 04, 2019 at 10:31:39PM +0200, Boaz Harrosh wrote:
> On 01/02/19 09:55, Christoph Hellwig wrote:
> > The only real user of the T10 OSD protocol, the pNFS object layout
> > driver never went to the point of having shipping products, and we
> > removed it 1.5 years ago.  Exofs is just a simple example without
> > real life users.
> > 
> > The code has been mostly unmaintained for years and is getting in the
> > way of block / SCSI changes, 
> 
> For the 4th time: Which ?

Speeding up the I/O path for example.  Making sense of SCSI
command allocation for another.  Having to deal with sense data
handling for the duplicate scsi command allocation as a third.