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Last 3 patches for bidi support

PATCH New Boaz Harrosh 2 participants 7 messages Dec 13, 2007 – Jan 6, 2008

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#0 lore raw

cover Last 3 patches for bidi support

James hi.

Bidi patches just broke again, by a patch that fixes some to-be-dead code. (scsi: BUG_ON() impossible condition)

Could it not just be accepted into the tree now. It sat in -mm tree with no reports of breakage or complains. What are we waiting for? the way I see it there is nothing holding it back, it's not even dangerous anymore.

You need Arm's accessors patch from scsi-pending Russell King <[email protected]>
Please send an Acked-by for this patch

and the patch that removes the old esp drivers
(http://www.spinics.net/lists/linux-scsi/msg20914.html)

Christoph Hellwig <[email protected]>
David S. Miller <[email protected]>
Maciej W. Rozycki <[email protected]>

Please send an Ack-by or Recommended-by to the removal of these old esp drivers.

And the 3 patches (based on scsi-misc)
[1] tgt: Use scsi_init_io instead of scsi_alloc_sgtable Was Ack-by the maintainer of tgt. Please accept independent of the other 2.

[2] scsi: scsi_data_buffer
The move to scsi_data_buffer. From here on any unconverted driver will not compile.

[3] scsi: bidi support
Actual very simple really.

All parties involved, send your reservations if any NOW. Else James please put it in.

Andrew could they be included back into -mm tree?

Boaz

#1 lore raw

PATCH 1/1 tgt: Use scsi_init_io instead of scsi_alloc_sgtable

- If we export scsi_init_io()/scsi_release_buffers() instead of scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more insulated from scsi_lib changes. As a bonus it will also gain bidi capability when it comes.

---
 drivers/scsi/scsi_lib.c     |   21 ++++++++++-----------
 drivers/scsi/scsi_tgt_lib.c |   29 +++++------------------------
 include/scsi/scsi_cmnd.h    |    4 ++--
 3 files changed, 17 insertions(+), 37 deletions(-)
drivers/scsi/scsi_lib.c +10 -11
index e273e4b..d1a4671 100644
@@ -739,7 +739,8 @@ static inline unsigned int scsi_sgtable_index(unsigned short nents)
 	return index;
 }
 
-struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask)
+static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd,
+								gfp_t gfp_mask)
 {
 	struct scsi_host_sg_pool *sgp;
 	struct scatterlist *sgl, *prev, *ret;
@@ -825,9 +826,7 @@ enomem:
 	return NULL;
 }
 
-EXPORT_SYMBOL(scsi_alloc_sgtable);
-
-void scsi_free_sgtable(struct scsi_cmnd *cmd)
+static void scsi_free_sgtable(struct scsi_cmnd *cmd)
 {
 	struct scatterlist *sgl = cmd->request_buffer;
 	struct scsi_host_sg_pool *sgp;
@@ -873,8 +872,6 @@ void scsi_free_sgtable(struct scsi_cmnd *cmd)
 	mempool_free(sgl, sgp->pool);
 }
 
-EXPORT_SYMBOL(scsi_free_sgtable);
-
 /*
  * Function:    scsi_release_buffers()
  *
@@ -892,7 +889,7 @@ EXPORT_SYMBOL(scsi_free_sgtable);
  *		the scatter-gather table, and potentially any bounce
  *		buffers.
  */
-static void scsi_release_buffers(struct scsi_cmnd *cmd)
+void scsi_release_buffers(struct scsi_cmnd *cmd)
 {
 	if (cmd->use_sg)
 		scsi_free_sgtable(cmd);
@@ -904,6 +901,7 @@ static void scsi_release_buffers(struct scsi_cmnd *cmd)
 	cmd->request_buffer = NULL;
 	cmd->request_bufflen = 0;
 }
+EXPORT_SYMBOL(scsi_release_buffers);
 
 /*
  * Function:    scsi_io_completion()
@@ -1105,7 +1103,7 @@ void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
  * Returns:     0 on success
  *		BLKPREP_DEFER if the failure is retryable
  */
-static int scsi_init_io(struct scsi_cmnd *cmd)
+int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
 	struct request     *req = cmd->request;
 	int		   count;
@@ -1120,7 +1118,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
 	/*
 	 * If sg table allocation fails, requeue request later.
 	 */
-	cmd->request_buffer = scsi_alloc_sgtable(cmd, GFP_ATOMIC);
+	cmd->request_buffer = scsi_alloc_sgtable(cmd, gfp_mask);
 	if (unlikely(!cmd->request_buffer)) {
 		scsi_unprep_request(req);
 		return BLKPREP_DEFER;
@@ -1141,6 +1139,7 @@ static int scsi_init_io(struct scsi_cmnd *cmd)
 	cmd->use_sg = count;
 	return BLKPREP_OK;
 }
+EXPORT_SYMBOL(scsi_init_io);
 
 static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
 		struct request *req)
@@ -1186,7 +1185,7 @@ int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
 
 		BUG_ON(!req->nr_phys_segments);
 
-		ret = scsi_init_io(cmd);
+		ret = scsi_init_io(cmd, GFP_ATOMIC);
 		if (unlikely(ret))
 			return ret;
 	} else {
@@ -1237,7 +1236,7 @@ int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
 	if (unlikely(!cmd))
 		return BLKPREP_DEFER;
 
-	return scsi_init_io(cmd);
+	return scsi_init_io(cmd, GFP_ATOMIC);
 }
 EXPORT_SYMBOL(scsi_setup_fs_cmnd);
 
drivers/scsi/scsi_tgt_lib.c +5 -24
index 93ece8f..91630ba 100644
@@ -331,8 +331,7 @@ static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
 
 	scsi_tgt_uspace_send_status(cmd, tcmd->itn_id, tcmd->tag);
 
-	if (scsi_sglist(cmd))
-		scsi_free_sgtable(cmd);
+	scsi_release_buffers(cmd);
 
 	queue_work(scsi_tgtd, &tcmd->work);
 }
@@ -353,26 +352,6 @@ static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
 	return 0;
 }
 
-static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
-{
-	struct request *rq = cmd->request;
-	int count;
-
-	cmd->use_sg = rq->nr_phys_segments;
-	cmd->request_buffer = scsi_alloc_sgtable(cmd, gfp_mask);
-	if (!cmd->request_buffer)
-		return -ENOMEM;
-
-	cmd->request_bufflen = rq->data_len;
-
-	dprintk("cmd %p cnt %d %lu\n", cmd, scsi_sg_count(cmd),
-		rq_data_dir(rq));
-	count = blk_rq_map_sg(rq->q, rq, scsi_sglist(cmd));
-	BUG_ON(count > cmd->use_sg);
-	cmd->use_sg = count;
-	return 0;
-}
-
 /* TODO: test this crap and replace bio_map_user with new interface maybe */
 static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
 			       unsigned long uaddr, unsigned int len, int rw)
@@ -398,9 +377,11 @@ static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
 	}
 
 	tcmd->bio = rq->bio;
-	err = scsi_tgt_init_cmd(cmd, GFP_KERNEL);
-	if (err)
+	err = scsi_init_io(cmd, GFP_KERNEL);
+	if (err) {
+		scsi_release_buffers(cmd);
 		goto unmap_rq;
+	}
 
 	return 0;
 
include/scsi/scsi_cmnd.h +2 -2
index 3f47e52..a7be605 100644
@@ -128,8 +128,8 @@ extern void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count,
 				 size_t *offset, size_t *len);
 extern void scsi_kunmap_atomic_sg(void *virt);
 
-extern struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *, gfp_t);
-extern void scsi_free_sgtable(struct scsi_cmnd *);
+extern int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask);
+extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 
 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
Signature · 1 line
1.5.3.3
maintainer
#2 lore raw

Re: [PATCH] tgt: Use scsi_init_io instead of scsi_alloc_sgtable

Quoted 7 lines · Boaz Harrosh

- If we export scsi_init_io()/scsi_release_buffers() instead of scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more insulated from scsi_lib changes. As a bonus it will also gain bidi capability when it comes.

I'm afraid the reversion of ->done removal broke the application of this yet again ... could you respin.

Thanks,

James

#3 lore raw

Re: [PATCH] tgt: Use scsi_init_io instead of scsi_alloc_sgtable

Quoted 9 lines · James Bottomley
Quoted 7 lines · Boaz Harrosh

- If we export scsi_init_io()/scsi_release_buffers() instead of scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more insulated from scsi_lib changes. As a bonus it will also gain bidi capability when it comes.

Quoted 7 lines

I'm afraid the reversion of ->done removal broke the application of this yet again ... could you respin.

Thanks,

James

It looks like the revert is to be reverted ;)
I have rebased, but should I wait a while to
see if they're needed?

Boaz

maintainer
#4 lore raw

Re: [PATCH] tgt: Use scsi_init_io instead of scsi_alloc_sgtable

Quoted 13 lines · Boaz Harrosh
Quoted 12 lines · James Bottomley
Quoted 7 lines · Boaz Harrosh

- If we export scsi_init_io()/scsi_release_buffers() instead of scsi_{alloc,free}_sgtable() from scsi_lib than tgt code is much more insulated from scsi_lib changes. As a bonus it will also gain bidi capability when it comes.

I'm afraid the reversion of ->done removal broke the application of this yet again ... could you respin.

Quoted 7 lines
Quoted 4 lines

Thanks,

James

It looks like the revert is to be reverted ;)
I have rebased, but should I wait a while to
see if they're needed?

Yes, let's just wait a while to see what the outcome is ...

James

#5 lore raw

PATCH 1/1 scsi: scsi_data_buffer

In reply to Boaz Harrosh

In preparation for bidi we abstract all IO members of scsi_cmnd, that will need to duplicate, into a substructure.

- Group all IO members of scsi_cmnd into a scsi_data_buffer structure.
- Adjust accessors to new members.
- scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of scsi_cmnd. And work on it.
- Adjust scsi_init_io() and scsi_release_buffers() for above change.
- Fix other parts of scsi_lib/scsi.c to members migration. Use accessors where appropriate.

- fix Documentation about scsi_cmnd in scsi_host.h

- scsi_error.c
* Changed needed members of struct scsi_eh_save.
* Careful considerations in scsi_eh_prep/restore_cmnd.

- sd.c and sr.c
* sd and sr would adjust IO size to align on device's block size so code needs to change once we move to scsi_data_buff implementation.
* Convert code to use scsi_for_each_sg
* Use data accessors where appropriate.

- tgt: convert libsrp to use scsi_data_buffer
- isd200: This driver still bangs on scsi_cmnd IO members, so need changing

---
 drivers/scsi/libsrp.c        |    4 +-
 drivers/scsi/scsi.c          |    2 +-
 drivers/scsi/scsi_error.c    |   28 +++++----------
 drivers/scsi/scsi_lib.c      |   77 ++++++++++++++++--------------------------
 drivers/scsi/sd.c            |    4 +-
 drivers/scsi/sr.c            |   25 +++++++------
 drivers/usb/storage/isd200.c |    8 ++--
 include/scsi/scsi_cmnd.h     |   39 +++++++++++++--------
 include/scsi/scsi_eh.h       |    8 ++---
 include/scsi/scsi_host.h     |    4 +-
 10 files changed, 91 insertions(+), 108 deletions(-)
drivers/scsi/libsrp.c +2 -2
index 5cff020..8a8562a 100644
@@ -426,8 +426,8 @@ int srp_cmd_queue(struct Scsi_Host *shost, struct srp_cmd *cmd, void *info,
 
 	sc->SCp.ptr = info;
 	memcpy(sc->cmnd, cmd->cdb, MAX_COMMAND_SIZE);
-	sc->request_bufflen = len;
-	sc->request_buffer = (void *) (unsigned long) addr;
+	sc->sdb.length = len;
+	sc->sdb.sglist = (void *) (unsigned long) addr;
 	sc->tag = tag;
 	err = scsi_tgt_queue_command(sc, itn_id, (struct scsi_lun *)&cmd->lun,
 				     cmd->tag);
drivers/scsi/scsi.c +1 -1
index ebc0193..a0fd785 100644
@@ -712,7 +712,7 @@ void scsi_finish_command(struct scsi_cmnd *cmd)
 				"Notifying upper driver of completion "
 				"(result %x)\n", cmd->result));
 
-	good_bytes = cmd->request_bufflen;
+	good_bytes = scsi_bufflen(cmd);
         if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
 		drv = scsi_cmd_to_driver(cmd);
 		if (drv->done)
drivers/scsi/scsi_error.c +10 -18
index 169bc59..241ab48 100644
@@ -617,29 +617,25 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 	ses->cmd_len = scmd->cmd_len;
 	memcpy(ses->cmnd, scmd->cmnd, sizeof(scmd->cmnd));
 	ses->data_direction = scmd->sc_data_direction;
-	ses->bufflen = scmd->request_bufflen;
-	ses->buffer = scmd->request_buffer;
-	ses->use_sg = scmd->use_sg;
-	ses->resid = scmd->resid;
+	ses->sdb = scmd->sdb;
 	ses->result = scmd->result;
 
+	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
+
 	if (sense_bytes) {
-		scmd->request_bufflen = min_t(unsigned,
+		scmd->sdb.length = min_t(unsigned,
 		                       sizeof(scmd->sense_buffer), sense_bytes);
 		sg_init_one(&ses->sense_sgl, scmd->sense_buffer,
-		                                       scmd->request_bufflen);
-		scmd->request_buffer = &ses->sense_sgl;
+							      scmd->sdb.length);
+		scmd->sdb.sglist = &ses->sense_sgl;
 		scmd->sc_data_direction = DMA_FROM_DEVICE;
-		scmd->use_sg = 1;
+		scmd->sdb.sg_count = 1;
 		memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
 		scmd->cmnd[0] = REQUEST_SENSE;
-		scmd->cmnd[4] = scmd->request_bufflen;
+		scmd->cmnd[4] = scmd->sdb.length;
 		scmd->cmd_len = COMMAND_SIZE(scmd->cmnd[0]);
 	} else {
-		scmd->request_buffer = NULL;
-		scmd->request_bufflen = 0;
 		scmd->sc_data_direction = DMA_NONE;
-		scmd->use_sg = 0;
 		if (cmnd) {
 			memset(scmd->cmnd, 0, sizeof(scmd->cmnd));
 			memcpy(scmd->cmnd, cmnd, cmnd_size);
@@ -676,10 +672,7 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 	scmd->cmd_len = ses->cmd_len;
 	memcpy(scmd->cmnd, ses->cmnd, sizeof(scmd->cmnd));
 	scmd->sc_data_direction = ses->data_direction;
-	scmd->request_bufflen = ses->bufflen;
-	scmd->request_buffer = ses->buffer;
-	scmd->use_sg = ses->use_sg;
-	scmd->resid = ses->resid;
+	scmd->sdb = ses->sdb;
 	scmd->result = ses->result;
 }
 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
@@ -1700,8 +1693,7 @@ scsi_reset_provider(struct scsi_device *dev, int flag)
 	memset(&scmd->cmnd, '\0', sizeof(scmd->cmnd));
     
 	scmd->scsi_done		= scsi_reset_provider_done_command;
-	scmd->request_buffer		= NULL;
-	scmd->request_bufflen		= 0;
+	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
 
 	scmd->cmd_len			= 0;
 
drivers/scsi/scsi_lib.c +29 -48

186 lines not on this page · raw message

drivers/scsi/sd.c +2 -2
index e6d85b0..1fcec1e 100644
@@ -507,7 +507,7 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
 		SCpnt->cmnd[4] = (unsigned char) this_count;
 		SCpnt->cmnd[5] = 0;
 	}
-	SCpnt->request_bufflen = this_count * sdp->sector_size;
+	SCpnt->sdb.length = this_count * sdp->sector_size;
 
 	/*
 	 * We shouldn't disconnect in the middle of a sector, so with a dumb
@@ -914,7 +914,7 @@ static struct block_device_operations sd_fops = {
 static int sd_done(struct scsi_cmnd *SCpnt)
 {
 	int result = SCpnt->result;
- 	unsigned int xfer_size = SCpnt->request_bufflen;
+	unsigned int xfer_size = scsi_bufflen(SCpnt);
  	unsigned int good_bytes = result ? 0 : xfer_size;
  	u64 start_lba = SCpnt->request->sector;
  	u64 bad_lba;
drivers/scsi/sr.c +13 -12
index 7128d15..93d9dc8 100644
@@ -233,7 +233,7 @@ out:
 static int sr_done(struct scsi_cmnd *SCpnt)
 {
 	int result = SCpnt->result;
-	int this_count = SCpnt->request_bufflen;
+	int this_count = scsi_bufflen(SCpnt);
 	int good_bytes = (result == 0 ? this_count : 0);
 	int block_sectors = 0;
 	long error_sector;
@@ -378,17 +378,18 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
 	}
 
 	{
-		struct scatterlist *sg = SCpnt->request_buffer;
-		int i, size = 0;
-		for (i = 0; i < SCpnt->use_sg; i++)
-			size += sg[i].length;
+		struct scatterlist *sg;
+		int i, size = 0, sg_count = scsi_sg_count(SCpnt);
 
-		if (size != SCpnt->request_bufflen && SCpnt->use_sg) {
+		scsi_for_each_sg(SCpnt, sg, sg_count, i)
+			size += sg->length;
+
+		if (size != scsi_bufflen(SCpnt)) {
 			scmd_printk(KERN_ERR, SCpnt,
 				"mismatch count %d, bytes %d\n",
-				size, SCpnt->request_bufflen);
-			if (SCpnt->request_bufflen > size)
-				SCpnt->request_bufflen = size;
+				size, scsi_bufflen(SCpnt));
+			if (scsi_bufflen(SCpnt) > size)
+				SCpnt->sdb.length = size;
 		}
 	}
 
@@ -396,12 +397,12 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
 	 * request doesn't start on hw block boundary, add scatter pads
 	 */
 	if (((unsigned int)rq->sector % (s_size >> 9)) ||
-	    (SCpnt->request_bufflen % s_size)) {
+	    (scsi_bufflen(SCpnt) % s_size)) {
 		scmd_printk(KERN_NOTICE, SCpnt, "unaligned transfer\n");
 		goto out;
 	}
 
-	this_count = (SCpnt->request_bufflen >> 9) / (s_size >> 9);
+	this_count = (scsi_bufflen(SCpnt) >> 9) / (s_size >> 9);
 
 
 	SCSI_LOG_HLQUEUE(2, printk("%s : %s %d/%ld 512 byte blocks.\n",
@@ -415,7 +416,7 @@ static int sr_prep_fn(struct request_queue *q, struct request *rq)
 
 	if (this_count > 0xffff) {
 		this_count = 0xffff;
-		SCpnt->request_bufflen = this_count * s_size;
+		SCpnt->sdb.length = this_count * s_size;
 	}
 
 	SCpnt->cmnd[2] = (unsigned char) (block >> 24) & 0xff;
drivers/usb/storage/isd200.c +4 -4
index 178e8c2..2d9a32b 100644
@@ -415,14 +415,14 @@ static void isd200_set_srb(struct isd200_info *info,
 		sg_init_one(&info->sg, buff, bufflen);
 
 	srb->sc_data_direction = dir;
-	srb->request_buffer = buff ? &info->sg : NULL;
-	srb->request_bufflen = bufflen;
-	srb->use_sg = buff ? 1 : 0;
+	srb->sdb.sglist = buff ? &info->sg : NULL;
+	srb->sdb.length = bufflen;
+	srb->sdb.sg_count = buff ? 1 : 0;
 }
 
 static void isd200_srb_set_bufflen(struct scsi_cmnd *srb, unsigned bufflen)
 {
-	srb->request_bufflen = bufflen;
+	srb->sdb.length = bufflen;
 }
 
 
include/scsi/scsi_cmnd.h +25 -14
index a7be605..887a12a 100644
@@ -12,6 +12,13 @@ struct scatterlist;
 struct Scsi_Host;
 struct scsi_device;
 
+struct scsi_data_buffer {
+	struct scatterlist *sglist;
+	unsigned length;
+	int resid;
+	unsigned short sg_count;
+	unsigned short alloc_sg_count; /* private to scsi_lib */
+};
 
 /* embedded in scsi_cmnd */
 struct scsi_pointer {
@@ -62,15 +69,10 @@ struct scsi_cmnd {
 	/* These elements define the operation we are about to perform */
 #define MAX_COMMAND_SIZE	16
 	unsigned char cmnd[MAX_COMMAND_SIZE];
-	unsigned request_bufflen;	/* Actual request size */
 
 	struct timer_list eh_timeout;	/* Used to time out the command. */
-	void *request_buffer;		/* Actual requested buffer */
 
 	/* These elements define the operation we ultimately want to perform */
-	unsigned short use_sg;	/* Number of pieces of scatter-gather */
-	unsigned short __use_sg;
-
 	unsigned underflow;	/* Return error if less than
 				   this amount is transferred */
 
@@ -80,10 +82,6 @@ struct scsi_cmnd {
 				   reconnects.   Probably == sector
 				   size */
 
-	int resid;		/* Number of bytes requested to be
-				   transferred less actual number
-				   transferred (0 if not supported) */
-
 	struct request *request;	/* The command we are
 				   	   working on */
 
@@ -114,6 +112,8 @@ struct scsi_cmnd {
 	int result;		/* Status code from lower level driver */
 
 	unsigned char tag;	/* SCSI-II queued command tag */
+
+	struct scsi_data_buffer sdb;
 };
 
 extern struct scsi_cmnd *scsi_get_command(struct scsi_device *, gfp_t);
@@ -134,18 +134,29 @@ extern void scsi_release_buffers(struct scsi_cmnd *cmd);
 extern int scsi_dma_map(struct scsi_cmnd *cmd);
 extern void scsi_dma_unmap(struct scsi_cmnd *cmd);
 
-#define scsi_sg_count(cmd) ((cmd)->use_sg)
-#define scsi_sglist(cmd) ((struct scatterlist *)(cmd)->request_buffer)
-#define scsi_bufflen(cmd) ((cmd)->request_bufflen)
+static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
+{
+	return cmd->sdb.sg_count;
+}
+
+static inline struct scatterlist *scsi_sglist(struct scsi_cmnd *cmd)
+{
+	return cmd->sdb.sglist;
+}
+
+static inline unsigned scsi_bufflen(struct scsi_cmnd *cmd)
+{
+	return cmd->sdb.length;
+}
 
 static inline void scsi_set_resid(struct scsi_cmnd *cmd, int resid)
 {
-	cmd->resid = resid;
+	cmd->sdb.resid = resid;
 }
 
 static inline int scsi_get_resid(struct scsi_cmnd *cmd)
 {
-	return cmd->resid;
+	return cmd->sdb.resid;
 }
 
 #define scsi_for_each_sg(cmd, sg, nseg, __i)			\
include/scsi/scsi_eh.h +3 -5
index d21b891..1e08be1 100644
@@ -68,16 +68,14 @@ extern int scsi_get_sense_info_fld(const u8 * sense_buffer, int sb_len,
 extern int scsi_reset_provider(struct scsi_device *, int);
 
 struct scsi_eh_save {
+	/* saved state */
 	int result;
 	enum dma_data_direction data_direction;
 	unsigned char cmd_len;
 	unsigned char cmnd[MAX_COMMAND_SIZE];
+	struct scsi_data_buffer sdb;
 
-	void *buffer;
-	unsigned bufflen;
-	unsigned short use_sg;
-	int resid;
-
+	/* new command support */
 	struct scatterlist sense_sgl;
 };
 
include/scsi/scsi_host.h +2 -2
index 0fd4746..cb2bcab 100644
@@ -136,9 +136,9 @@ struct scsi_host_template {
 	 * the done callback is invoked.
 	 *
 	 * This is called to inform the LLD to transfer
-	 * cmd->request_bufflen bytes. The cmd->use_sg speciefies the
+	 * scsi_bufflen(cmd) bytes. scsi_sg_count(cmd) speciefies the
 	 * number of scatterlist entried in the command and
-	 * cmd->request_buffer contains the scatterlist.
+	 * scsi_sglist(cmd) returns the scatterlist.
 	 *
 	 * return values: see queuecommand
 	 *
Signature · 1 line
1.5.3.3
#6 lore raw

PATCH 1/1 scsi: bidi support

In reply to Boaz Harrosh

At the block level bidi request uses req->next_rq pointer for a second bidi_read request.
At Scsi-midlayer a second scsi_data_buffer structure is used for the bidi_read part. This bidi scsi_data_buffer is put on request->next_rq->special. Struct scsi_cmnd is not changed.

- Define scsi_bidi_cmnd() to return true if it is a bidi request and a second sgtable was allocated.

- Define scsi_in()/scsi_out() to return the in or out scsi_data_buffer from this command This API is to isolate users from the mechanics of bidi.

- Define scsi_end_bidi_request() to do what scsi_end_request() does but for a bidi request. This is necessary because bidi commands are a bit tricky here. (See comments in body)

- scsi_release_buffers() will also release the bidi_read scsi_data_buffer

- scsi_io_completion() on bidi commands will now call scsi_end_bidi_request() and return.

- The previous work done in scsi_init_io() is now done in a new scsi_init_sgtable() (which is 99% identical to old scsi_init_io()) The new scsi_init_io() will call the above twice if needed also for the bidi_read command. Only at this point is a command bidi.

- In scsi_error.c at scsi_eh_prep/restore_cmnd() make sure bidi-lld is not confused by a get-sense command that looks like bidi. This is done by puting NULL at request->next_rq, and restoring.

---
 drivers/scsi/scsi_error.c |    3 +
 drivers/scsi/scsi_lib.c   |  144 ++++++++++++++++++++++++++++++++++++---------
 include/scsi/scsi_cmnd.h  |   23 +++++++-
 include/scsi/scsi_eh.h    |    1 +
 4 files changed, 141 insertions(+), 30 deletions(-)
drivers/scsi/scsi_error.c +3 -0
index 241ab48..5c8ba6a 100644
@@ -618,9 +618,11 @@ void scsi_eh_prep_cmnd(struct scsi_cmnd *scmd, struct scsi_eh_save *ses,
 	memcpy(ses->cmnd, scmd->cmnd, sizeof(scmd->cmnd));
 	ses->data_direction = scmd->sc_data_direction;
 	ses->sdb = scmd->sdb;
+	ses->next_rq = scmd->request->next_rq;
 	ses->result = scmd->result;
 
 	memset(&scmd->sdb, 0, sizeof(scmd->sdb));
+	scmd->request->next_rq = NULL;
 
 	if (sense_bytes) {
 		scmd->sdb.length = min_t(unsigned,
@@ -673,6 +675,7 @@ void scsi_eh_restore_cmnd(struct scsi_cmnd* scmd, struct scsi_eh_save *ses)
 	memcpy(scmd->cmnd, ses->cmnd, sizeof(scmd->cmnd));
 	scmd->sc_data_direction = ses->data_direction;
 	scmd->sdb = ses->sdb;
+	scmd->request->next_rq = ses->next_rq;
 	scmd->result = ses->result;
 }
 EXPORT_SYMBOL(scsi_eh_restore_cmnd);
drivers/scsi/scsi_lib.c +115 -29

208 lines not on this page · raw message

include/scsi/scsi_cmnd.h +22 -1
index 887a12a..cd2851a 100644
@@ -2,12 +2,12 @@
 #define _SCSI_SCSI_CMND_H
 
 #include <linux/dma-mapping.h>
+#include <linux/blkdev.h>
 #include <linux/list.h>
 #include <linux/types.h>
 #include <linux/timer.h>
 #include <linux/scatterlist.h>
 
-struct request;
 struct scatterlist;
 struct Scsi_Host;
 struct scsi_device;
@@ -162,4 +162,25 @@ 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)
+{
+	WARN_ON((cmd->sc_data_direction != DMA_FROM_DEVICE) &&
+							!scsi_bidi_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)
+{
+	WARN_ON((cmd->sc_data_direction != DMA_TO_DEVICE) &&
+							!scsi_bidi_cmnd(cmd));
+	return &cmd->sdb;
+}
+
 #endif /* _SCSI_SCSI_CMND_H */
include/scsi/scsi_eh.h +1 -0
index 1e08be1..25071d5 100644
@@ -74,6 +74,7 @@ struct scsi_eh_save {
 	unsigned char cmd_len;
 	unsigned char cmnd[MAX_COMMAND_SIZE];
 	struct scsi_data_buffer sdb;
+	struct request *next_rq;
 
 	/* new command support */
 	struct scatterlist sense_sgl;
Signature · 1 line
1.5.3.3