remove exofs and the T10 OSD code V2

This was an example for using the SCSI OSD protocol, which we're trying to remove.

Now that all the users are gone the SCSI OSD library can be removed as well.

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, 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 ;-)"

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, 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 ;-)"

LGTM, for both:

From d6dd4f32798edd425a4df72f6125dba03e19d8c7 Mon Sep 17 00:00:00 2001

Quoted 1 line · Jens Axboe

LGTM, for both:

I also have this one on top as requested by Martin. The core block bidi support is unfortunately also used by bsg-lib, although it is not anywhere near as invasive. But that is another argument for looking into moving bsg-lib away from using block queues..

---

Quoted 1 line

Quoted 1 line

From d6dd4f32798edd425a4df72f6125dba03e19d8c7 Mon Sep 17 00:00:00 2001

From: Christoph Hellwig <[email protected]>
Date: Sat, 27 Oct 2018 15:49:13 +0200
Subject: scsi: remove bidirectional command support

Signed-off-by Christoph Hellwig <[email protected]>

---
 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            | 80 ++----------------------------
 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(+), 253 deletions(-)

drivers/scsi/cxgbi/libcxgbi.c +5 -8

index 75f876409fb9..4466ae5c9a74 100644
@@ -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;
 

drivers/scsi/iscsi_tcp.c +1 -8

index 23354f206533..a78b46bb2b71 100644
@@ -514,7 +514,7 @@ 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,

@@ -948,12 +948,6 @@ 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);

@@ -981,7 +975,6 @@ 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,
 	.use_clustering         = DISABLE_CLUSTERING,
-	.slave_alloc            = iscsi_sw_tcp_slave_alloc,
 	.slave_configure        = iscsi_sw_tcp_slave_configure,
 	.target_alloc		= iscsi_target_alloc,
 	.proc_name		= "iscsi_tcp",

drivers/scsi/libiscsi.c +6 -58

index 93c66ebad907..a6dec983c30e 100644
@@ -218,32 +218,6 @@ 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

@@ -382,13 +356,6 @@ 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;
 

@@ -463,12 +430,10 @@ 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;

@@ -637,12 +602,7 @@ 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);

@@ -897,14 +857,7 @@ 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 |

@@ -951,8 +904,8 @@ 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;
 	}

@@ -1794,12 +1747,7 @@ 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;
 }

drivers/scsi/libiscsi_tcp.c +4 -4

index 4fcb9e65be57..1ec8332df515 100644
@@ -491,7 +491,7 @@ 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

@@ -576,11 +576,11 @@ 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;
 	}
 

@@ -692,7 +692,7 @@ 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

drivers/scsi/scsi_debug.c +9 -42

index 60bcc6df97a9..98b212ec6240 100644
@@ -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;
 }
 

drivers/scsi/scsi_error.c +0 -3

index c736d61b1648..42dd49961ca5 100644
@@ -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;

drivers/scsi/scsi_lib.c +4 -76

index c7fccbb8f554..cae0a5f7539d 100644
@@ -610,11 +610,6 @@ 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);
 }

@@ -653,18 +648,9 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd)
 		sg_free_table_chained(&cmd->prot_sdb->table, false);
 }
 
-static void scsi_release_bidi_buffers(struct scsi_cmnd *cmd)
-{
-	struct scsi_data_buffer *bidi_sdb = cmd->request->next_rq->special;
-
-	sg_free_table_chained(&bidi_sdb->table, false);
-	kmem_cache_free(scsi_sdb_cache, bidi_sdb);
-	cmd->request->next_rq->special = NULL;
-}
-
 /* 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;

@@ -673,11 +659,6 @@ 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);
 

@@ -707,8 +688,6 @@ static bool scsi_end_request(struct request *req, blk_status_t error,
 	} else {
 		unsigned long flags;
 
-		if (bidi_bytes)
-			scsi_release_bidi_buffers(cmd);
 		scsi_release_buffers(cmd);
 		scsi_put_command(cmd);
 

@@ -916,7 +895,7 @@ 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:

@@ -1051,29 +1030,6 @@ 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;
 	}
 
 	/*

@@ -1090,13 +1046,13 @@ 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;

@@ -1159,23 +1115,6 @@ int scsi_init_io(struct scsi_cmnd *cmd)
 	if (error)
 		goto err_exit;
 
-	if (blk_bidi_rq(rq)) {
-		if (!rq->q->mq_ops) {
-			struct scsi_data_buffer *bidi_sdb =
-				kmem_cache_zalloc(scsi_sdb_cache, GFP_ATOMIC);
-			if (!bidi_sdb) {
-				error = BLKPREP_DEFER;
-				goto err_exit;
-			}
-
-			rq->next_rq->special = bidi_sdb;
-		}
-
-		error = scsi_init_sgtable(rq->next_rq, rq->next_rq->special);
-		if (error)
-			goto err_exit;
-	}
-
 	if (blk_integrity_rq(rq)) {
 		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
 		int ivecs, count;

@@ -2026,17 +1965,6 @@ static int 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);

drivers/scsi/virtio_scsi.c +3 -11

index 1c72db94270e..fd54c12a5ed3 100644
@@ -127,16 +127,8 @@ 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;
 }
 
 /**

@@ -430,9 +422,9 @@ 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.  */

drivers/target/loopback/tcm_loop.c +0 -15

index bc8918f382e4..a43bb76cccf6 100644
@@ -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,
 	.use_clustering		= DISABLE_CLUSTERING,
-	.slave_alloc		= tcm_loop_slave_alloc,
 	.module			= THIS_MODULE,
 	.track_queue_depth	= 1,
 };

drivers/usb/storage/uas.c +2 -9

index 1f7b401c4d04..1c3bff3d57b0 100644
@@ -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;
 

include/scsi/scsi_cmnd.h +1 -18

index c891ada3c5c2..681f0ca808d7 100644
@@ -209,23 +209,6 @@ 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)
 {

@@ -347,7 +330,7 @@ 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)

include/scsi/scsi_eh.h +0 -1

index 2b7e227960e1..3810b340551c 100644
@@ -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;

Quoted 8 lines · Christoph Hellwig

Quoted 1 line · Jens Axboe

LGTM, for both:

I also have this one on top as requested by Martin. The core block bidi support is unfortunately also used by bsg-lib, although it is not anywhere near as invasive. But that is another argument for looking into moving bsg-lib away from using block queues..

BUT this patch is very very wrong.

Totally apart from T10-OSD and its use in the field. Support for scsi BIDI commands is not exclusive to T10-OSD at all. Even the simple scsi-array command-set has BIDI operations defined. for example the write-return-xor and so on.

Also some private administrative CDBs of some vendor devices uses SCSI-BIDI. So this patch just broke some drivers. (User-mode apps use bsg pass through)

Also you might (try hard and) remove all usage of scsi-bidi as an initiator from the Linux Kernel. But what about target mode. As a target we have supported on the wire bidi protocols like write-return-xor and others for a long time. Are you willing to silently break all these setups in the field on the next update? Are you so sure these are never used?

PLEASE, I beg of you guys. Do not remove SCSI-BIDI. It is a cry of generations.

And I think by the rules of Linus, as far as target mode. You are not allowed to break users in this way.

Quoted 26 lines · Boaz Harrosh

Quoted 8 lines · Christoph Hellwig

Quoted 1 line · Jens Axboe

LGTM, for both:

I also have this one on top as requested by Martin. The core block bidi support is unfortunately also used by bsg-lib, although it is not anywhere near as invasive. But that is another argument for looking into moving bsg-lib away from using block queues..

BUT this patch is very very wrong.

Totally apart from T10-OSD and its use in the field. Support for scsi BIDI commands is not exclusive to T10-OSD at all. Even the simple scsi-array command-set has BIDI operations defined. for example the write-return-xor and so on.

Also some private administrative CDBs of some vendor devices uses SCSI-BIDI. So this patch just broke some drivers. (User-mode apps use bsg pass through)

Also you might (try hard and) remove all usage of scsi-bidi as an initiator from the Linux Kernel. But what about target mode. As a target we have supported on the wire bidi protocols like write-return-xor and others for a long time. Are you willing to silently break all these setups in the field on the next update? Are you so sure these are never used?

Quoted 4 lines

PLEASE, I beg of you guys. Do not remove SCSI-BIDI. It is a cry of generations.

And I think by the rules of Linus, as far as target mode. You are not allowed to break users in this way.

Hi,
I'm in the process of rebuilding the sg driver with the following goals:

- undo 20 years of road wear, some of which is caused by literally hundreds of "laparoscopic" patches that gradually ruin a driver, at least from the maintainer's viewpoint. Comments that once made sense become cryptic or just nonsense; naming schemes that obliterate variable names to the extent that a random name generator would be easier to follow; and just plain broken code. For example, why sort out the existing locking at a particular level when you can add a new lock in a completely non-orthogonal way? [Yes, I looking at you, google.] Anyway, my first cut at this is out there (on the linux-scsi list, see: "[PATCH v3 0/8] sg:
major cleanup, remove max_queue limit"). Not much new there, unless you look very closely

- the next step is to add to the sg driver async SCSI command capability based on the sg_io_v4 structure previously only used by the bsg driver and now removed from bsg. The main advantage of the sg_io_v4 structure over previous pass-through interface attempts is the support of SCSI bidi commands

- as part of this effort introduce two new ioctls: SG_IOSUBMIT and SG_IORECEIVE to replace the write()/read() technique currently in use (since Linux 1.0 in 1992). The write()/read() technique seems to be responsible for various security folks losing clumps of their hair. One advantage of ioctls, as Alan Cox pointed out, is the ability to write to and read back from the kernel in a way that is naturally synchronized. [Actually, those security folks shouldn't look too closely at sg_read() in that respect.]

In discussions with several folks who are on the T10 committee, I wondered why there was no READ GATHERED command (there has been a WRITE SCATTERED for 2 years). The answer was lack of interest ***, plus the difficultly of implementation. You see, READ GATHERED needs to send a scatter gather list to the device and get the corresponding data back (as a linear array). And that requires either:
a) bidi commands (scatter gather list in the data-out, corresponding "read" data in the data-in), or
b) loooong SCSI commands, up to around 256 bytes long in which the sgat list is the latter part of that command

And the T10 folks say neither of those options is well supported or is expensive.

I'm guessing they are referring to Linux and Windows.
I haven't argued much beyond that point, but it looks like a bit of a chicken and egg situation.

Don't know too much about the T10 OSD stuff. But I can see that it uses both long SCSI commands and a lot of bidi. IMO it seems to be 10 or 20 years before its time. Maybe ibm/redhat need to (re-)discover it for it to catch on.

Plus there are proprietary SCSI bidi commands out there. People contact me and ask me how to issue them with sg3_utils package. Easy, I tell them, just use sg_raw with a bsg device. Typically, in my experience, "no news is good news" after suggestions like that. When I give bad advice, I usually hear back relatively quickly. Anyone who wants SCSI bidi _async_ support is currently out of luck.

Enough already
Doug Gilbert

*** example: loading all or most kernel modules in a few READ SCATTERED
commands might speed up boot time ...

Quoted 74 lines · Douglas Gilbert

Quoted 26 lines · Boaz Harrosh

Quoted 8 lines · Christoph Hellwig

Quoted 1 line · Jens Axboe

LGTM, for both:

I also have this one on top as requested by Martin. The core block bidi support is unfortunately also used by bsg-lib, although it is not anywhere near as invasive. But that is another argument for looking into moving bsg-lib away from using block queues..

BUT this patch is very very wrong.

Totally apart from T10-OSD and its use in the field. Support for scsi BIDI commands is not exclusive to T10-OSD at all. Even the simple scsi-array command-set has BIDI operations defined. for example the write-return-xor and so on.

Also some private administrative CDBs of some vendor devices uses SCSI-BIDI. So this patch just broke some drivers. (User-mode apps use bsg pass through)

Also you might (try hard and) remove all usage of scsi-bidi as an initiator from the Linux Kernel. But what about target mode. As a target we have supported on the wire bidi protocols like write-return-xor and others for a long time. Are you willing to silently break all these setups in the field on the next update? Are you so sure these are never used?

Quoted 4 lines

PLEASE, I beg of you guys. Do not remove SCSI-BIDI. It is a cry of generations.

And I think by the rules of Linus, as far as target mode. You are not allowed to break users in this way.

Hi,
I'm in the process of rebuilding the sg driver with the following goals:

- undo 20 years of road wear, some of which is caused by literally hundreds of "laparoscopic" patches that gradually ruin a driver, at least from the maintainer's viewpoint. Comments that once made sense become cryptic or just nonsense; naming schemes that obliterate variable names to the extent that a random name generator would be easier to follow; and just plain broken code. For example, why sort out the existing locking at a particular level when you can add a new lock in a completely non-orthogonal way? [Yes, I looking at you, google.] Anyway, my first cut at this is out there (on the linux-scsi list, see: "[PATCH v3 0/8] sg:
major cleanup, remove max_queue limit"). Not much new there, unless you look very closely

- the next step is to add to the sg driver async SCSI command capability based on the sg_io_v4 structure previously only used by the bsg driver and now removed from bsg. The main advantage of the sg_io_v4 structure over previous pass-through interface attempts is the support of SCSI bidi commands

- as part of this effort introduce two new ioctls: SG_IOSUBMIT and SG_IORECEIVE to replace the write()/read() technique currently in use (since Linux 1.0 in 1992). The write()/read() technique seems to be responsible for various security folks losing clumps of their hair. One advantage of ioctls, as Alan Cox pointed out, is the ability to write to and read back from the kernel in a way that is naturally synchronized. [Actually, those security folks shouldn't look too closely at sg_read() in that respect.]

In discussions with several folks who are on the T10 committee, I wondered why there was no READ GATHERED command (there has been a WRITE SCATTERED for 2 years). The answer was lack of interest ***, plus the difficultly of implementation. You see, READ GATHERED needs to send a scatter gather list to the device and get the corresponding data back (as a linear array). And that requires either:
a) bidi commands (scatter gather list in the data-out, corresponding "read" data in the data-in), or
b) loooong SCSI commands, up to around 256 bytes long in which the sgat list is the latter part of that command

Quoted 2 lines

And the T10 folks say neither of those options is well supported or is expensive.

It is supported in Linux scsi/osd driver is a proof of that. And expensive it is not. I have demonstrated the ability to saturate a 10G link over a raid of devices from a single writer. In OSD everything is bidi.

Quoted 17 lines

I'm guessing they are referring to Linux and Windows.
I haven't argued much beyond that point, but it looks like a bit of a chicken and egg situation.

Don't know too much about the T10 OSD stuff. But I can see that it uses both long SCSI commands and a lot of bidi. IMO it seems to be 10 or 20 years before its time. Maybe ibm/redhat need to (re-)discover it for it to catch on.

Plus there are proprietary SCSI bidi commands out there. People contact me and ask me how to issue them with sg3_utils package. Easy, I tell them, just use sg_raw with a bsg device. Typically, in my experience, "no news is good news" after suggestions like that. When I give bad advice, I usually hear back relatively quickly. Anyone who wants SCSI bidi _async_ support is currently out of luck.

Quoted 1 line · Jens Axboe

LGTM, for both:

I also have this one on top as requested by Martin. The core block bidi support is unfortunately also used by bsg-lib, although it is not anywhere near as invasive. But that is another argument for looking into moving bsg-lib away from using block queues..

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, 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 ;-)"

Quoted 8 lines · 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, so I think it's finally time to drop it.

Quoted 6 lines

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 think I'm changing my mind about this.
[... ]

Quoted 11 lines · Boaz Harrosh

Quoted 10 lines · 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, so I think it's finally time to drop it.

Quote from Boaz:

Quoted 7 lines

Quoted 4 lines

"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 think I'm changing my mind about this.
[ ... ]

The osd driver was accepted in the upstream kernel in 2009. I have checked all commits in Linus' tree for the osd driver that went in since 2009. All changes made by other kernel developers than you are the result of tree-wide refactoring, compiler warning fixes, fixes for issues detected by static source code analyzers or spelling fixes. Hence my question: how big is the user base of the exofs and osd kernel drivers?

Thanks,
Bart.

Quoted 6 lines

[...] All changes made by other kernel developers than you are the result of tree-wide refactoring, compiler warning fixes, fixes for issues detected by static source code analyzers or spelling fixes. Hence my question: how big is the user base of the exofs and osd kernel drivers?

Not big at all. And none of them production setups. As I said mainly used by academia.

Thanks
Boaz

Quoted 2 lines

Thanks,
Bart.