Commit a1cf96ef authored by Pete Zaitcev's avatar Pete Zaitcev Committed by Greg Kroah-Hartman
Browse files

[PATCH] USB: ub 4: Zaitcev's quasi-S/G 



Back out Axboe-style quasi-S/G and replace it with one command and
repeated URBs. This is similar to what usb-storage does, only instead
of a few URBs allocated together, one URB is reused.

Jens's idea was very nice, but it collapsed when I had to support
packet commads for CD burning. I cannot issue two or more packet
commands where application expected only one.

However, burning does not work completely yet. The cdrecord starts,
recognizes the device, then aborts without writing a TOC.

Signed-off-by: default avatarPete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 6c1eb8c1

drivers/block/ub.c

+123 −164
Original line number Diff line number Diff line
@@ -235,27 +235,16 @@ struct ub_scsi_cmd { 


	int stat_count;			/* Retries getting status. */



	/*

	 * We do not support transfers from highmem pages

	 * because the underlying USB framework does not do what we need.

	 */

	char *data;			/* Requested buffer */

	unsigned int len;		/* Requested length */

	unsigned int current_sg;

	unsigned int nsg;		/* sgv[nsg] */

	struct scatterlist sgv[UB_MAX_REQ_SG];



	struct ub_lun *lun;

	void (*done)(struct ub_dev *, struct ub_scsi_cmd *);

	void *back;

};



struct ub_request {

	struct request *rq;

	unsigned char dir;

	unsigned int current_block;

	unsigned int current_sg;

	unsigned int nsg;		/* sgv[nsg] */

	struct scatterlist sgv[UB_MAX_REQ_SG];

};



/*

 */

struct ub_capacity {
@@ -351,8 +340,6 @@ struct ub_lun { 
	int readonly;

	int first_open;			/* Kludge. See ub_bd_open. */



	struct ub_request urq;



	/* Use Ingo's mempool if or when we have more than one command. */

	/*

	 * Currently we never need more than one command for the whole device.
@@ -410,19 +397,16 @@ static void ub_cleanup(struct ub_dev *sc); 
static int ub_request_fn_1(struct ub_lun *lun, struct request *rq);

static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct request *rq);

static void ub_scsi_build_block(struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct ub_request *urq);

static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct request *rq);

static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd);

static void ub_end_rq(struct request *rq, int uptodate);

static int ub_request_advance(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_request *urq, struct ub_scsi_cmd *cmd);

static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd);

static void ub_urb_complete(struct urb *urb, struct pt_regs *pt);

static void ub_scsi_action(unsigned long _dev);

static void ub_scsi_dispatch(struct ub_dev *sc);

static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd);

static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd);

static void ub_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);

static int __ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);

static void ub_state_stat(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
@@ -793,8 +777,6 @@ static int ub_request_fn_1(struct ub_lun *lun, struct request *rq) 
		return 0;

	}



	if (lun->urq.rq != NULL)

		return -1;

	if ((cmd = ub_get_cmd(lun)) == NULL)

		return -1;

	memset(cmd, 0, sizeof(struct ub_scsi_cmd));
@@ -813,7 +795,7 @@ static int ub_request_fn_1(struct ub_lun *lun, struct request *rq) 
	cmd->state = UB_CMDST_INIT;

	cmd->lun = lun;

	cmd->done = ub_rw_cmd_done;

	cmd->back = &lun->urq;

	cmd->back = rq;



	cmd->tag = sc->tagcnt++;

	if (ub_submit_scsi(sc, cmd) != 0) {
@@ -828,22 +810,20 @@ static int ub_request_fn_1(struct ub_lun *lun, struct request *rq) 
static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct request *rq)

{

	struct ub_request *urq;

	int ub_dir;

	int n_elem;



	urq = &lun->urq;

	memset(urq, 0, sizeof(struct ub_request));

	unsigned int block, nblks;



	if (rq_data_dir(rq) == WRITE)

		ub_dir = UB_DIR_WRITE;

	else

		ub_dir = UB_DIR_READ;

	cmd->dir = ub_dir;



	/*

	 * get scatterlist from block layer

	 */

	n_elem = blk_rq_map_sg(lun->disk->queue, rq, &urq->sgv[0]);

	n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);

	if (n_elem <= 0) {

		printk(KERN_INFO "%s: failed request map (%d)\n",

		    sc->name, n_elem); /* P3 */
@@ -854,7 +834,7 @@ static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun, 
		    sc->name, n_elem);

		return -1;

	}

	urq->nsg = n_elem;

	cmd->nsg = n_elem;

	sc->sg_stat[n_elem]++;



	/*
@@ -863,29 +843,10 @@ static int ub_cmd_build_block(struct ub_dev *sc, struct ub_lun *lun, 
	 * The call to blk_queue_hardsect_size() guarantees that request

	 * is aligned, but it is given in terms of 512 byte units, always.

	 */

	urq->current_block = rq->sector >> lun->capacity.bshift;

	// nblks = rq->nr_sectors >> lun->capacity.bshift;

	block = rq->sector >> lun->capacity.bshift;

	nblks = rq->nr_sectors >> lun->capacity.bshift;



	urq->rq = rq;

	urq->current_sg = 0;

	urq->dir = ub_dir;



	ub_scsi_build_block(lun, cmd, urq);

	return 0;

}



static void ub_scsi_build_block(struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct ub_request *urq)

{

	struct scatterlist *sg;

	unsigned int block, nblks;



	sg = &urq->sgv[urq->current_sg];



	block = urq->current_block;

	nblks = sg->length >> (lun->capacity.bshift + 9);



	cmd->cdb[0] = (urq->dir == UB_DIR_READ)? READ_10: WRITE_10;

	cmd->cdb[0] = (ub_dir == UB_DIR_READ)? READ_10: WRITE_10;

	/* 10-byte uses 4 bytes of LBA: 2147483648KB, 2097152MB, 2048GB */

	cmd->cdb[2] = block >> 24;

	cmd->cdb[3] = block >> 16;
@@ -895,34 +856,15 @@ static void ub_scsi_build_block(struct ub_lun *lun, 
	cmd->cdb[8] = nblks;

	cmd->cdb_len = 10;



	cmd->dir = urq->dir;

	cmd->data = page_address(sg->page) + sg->offset;

	cmd->len = sg->length;

	cmd->len = rq->nr_sectors * 512;



	return 0;

}



static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_scsi_cmd *cmd, struct request *rq)

{

	struct ub_request *urq;



	urq = &lun->urq;

	memset(urq, 0, sizeof(struct ub_request));

	urq->rq = rq;

	sc->sg_stat[0]++;



	if (rq->data_len != 0 && rq->data == NULL) {

		static int do_print = 1;

		if (do_print) {

			printk(KERN_WARNING "%s: unmapped packet request"

			    " flags 0x%lx length %d\n",

			    sc->name, rq->flags, rq->data_len);

			do_print = 0;

		}

		return -1;

	}



	memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);

	cmd->cdb_len = rq->cmd_len;

	int n_elem;



	if (rq->data_len == 0) {

		cmd->dir = UB_DIR_NONE;
@@ -931,8 +873,29 @@ static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun, 
			cmd->dir = UB_DIR_WRITE;

		else

			cmd->dir = UB_DIR_READ;



	}



	/*

	 * get scatterlist from block layer

	 */

	n_elem = blk_rq_map_sg(lun->disk->queue, rq, &cmd->sgv[0]);

	if (n_elem < 0) {

		printk(KERN_INFO "%s: failed request map (%d)\n",

		    sc->name, n_elem); /* P3 */

		return -1;

	}

	cmd->data = rq->data;

	if (n_elem > UB_MAX_REQ_SG) {	/* Paranoia */

		printk(KERN_WARNING "%s: request with %d segments\n",

		    sc->name, n_elem);

		return -1;

	}

	cmd->nsg = n_elem;

	sc->sg_stat[n_elem]++;



	memcpy(&cmd->cdb, rq->cmd, rq->cmd_len);

	cmd->cdb_len = rq->cmd_len;



	cmd->len = rq->data_len;



	return 0;
@@ -940,34 +903,33 @@ static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_lun *lun, 


static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)

{

	struct request *rq = cmd->back;

	struct ub_lun *lun = cmd->lun;

	struct ub_request *urq = cmd->back;

	struct request *rq;

	int uptodate;



	rq = urq->rq;

	if (cmd->error == 0) {

		uptodate = 1;



		if (blk_pc_request(rq)) {

			if (cmd->act_len >= rq->data_len)

				rq->data_len = 0;

			else

				rq->data_len -= cmd->act_len;

		}

	} else {

		uptodate = 0;



		if (blk_pc_request(rq)) {

			/* UB_SENSE_SIZE is smaller than SCSI_SENSE_BUFFERSIZE */

			memcpy(rq->sense, sc->top_sense, UB_SENSE_SIZE);

			rq->sense_len = UB_SENSE_SIZE;

	}



	if (cmd->error == 0)

		uptodate = 1;

			if (sc->top_sense[0] != 0)

				rq->errors = SAM_STAT_CHECK_CONDITION;

			else

		uptodate = 0;



	if (cmd->error == 0 && urq->current_sg+1 < urq->nsg) {

		if (ub_request_advance(sc, lun, urq, cmd) == 0) {

			/* Stay on target... */

			return;

				rq->errors = DID_ERROR << 16;

		}

		uptodate = 0;

	}



	urq->rq = NULL;



	ub_put_cmd(lun, cmd);

	ub_end_rq(rq, uptodate);

	blk_start_queue(lun->disk->queue);
@@ -982,40 +944,6 @@ static void ub_end_rq(struct request *rq, int uptodate) 
	end_that_request_last(rq);

}



static int ub_request_advance(struct ub_dev *sc, struct ub_lun *lun,

    struct ub_request *urq, struct ub_scsi_cmd *cmd)

{

	struct scatterlist *sg;

	unsigned int nblks;



	/* XXX This is temporary, until we sort out S/G in packet requests. */

	if (blk_pc_request(urq->rq)) {

		printk(KERN_WARNING

		    "2-segment packet request completed\n"); /* P3 */

		return -1;

	}



	sg = &urq->sgv[urq->current_sg];

	nblks = sg->length >> (lun->capacity.bshift + 9);

	urq->current_block += nblks;

	urq->current_sg++;

	sg++;



	memset(cmd, 0, sizeof(struct ub_scsi_cmd));

	ub_scsi_build_block(lun, cmd, urq);

	cmd->state = UB_CMDST_INIT;

	cmd->lun = lun;

	cmd->done = ub_rw_cmd_done;

	cmd->back = &lun->urq;



	cmd->tag = sc->tagcnt++;

	if (ub_submit_scsi(sc, cmd) != 0) {

		return -1;

	}



	return 0;

}



/*

 * Submit a regular SCSI operation (not an auto-sense).

 *
@@ -1171,7 +1099,6 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd) 
{

	struct urb *urb = &sc->work_urb;

	struct bulk_cs_wrap *bcs;

	int pipe;

	int rc;



	if (atomic_read(&sc->poison)) {
@@ -1272,38 +1199,13 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd) 
			goto Bad_End;

		}



		if (cmd->dir == UB_DIR_NONE) {

		if (cmd->dir == UB_DIR_NONE || cmd->nsg < 1) {

			ub_state_stat(sc, cmd);

			return;

		}



		UB_INIT_COMPLETION(sc->work_done);



		if (cmd->dir == UB_DIR_READ)

			pipe = sc->recv_bulk_pipe;

		else

			pipe = sc->send_bulk_pipe;

		sc->last_pipe = pipe;

		usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,

		    cmd->data, cmd->len, ub_urb_complete, sc);

		sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;

		sc->work_urb.actual_length = 0;

		sc->work_urb.error_count = 0;

		sc->work_urb.status = 0;



		if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {

			/* XXX Clear stalls */

			printk("ub: data #%d submit failed (%d)\n", cmd->tag, rc); /* P3 */

			ub_complete(&sc->work_done);

			ub_state_done(sc, cmd, rc);

			return;

		}



		sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;

		add_timer(&sc->work_timer);



		cmd->state = UB_CMDST_DATA;

		ub_cmdtr_state(sc, cmd);

		// udelay(125);		// usb-storage has this

		ub_data_start(sc, cmd);



	} else if (cmd->state == UB_CMDST_DATA) {

		if (urb->status == -EPIPE) {
@@ -1325,16 +1227,22 @@ static void ub_scsi_urb_compl(struct ub_dev *sc, struct ub_scsi_cmd *cmd) 
		if (urb->status == -EOVERFLOW) {

			/*

			 * A babble? Failure, but we must transfer CSW now.

			 * XXX This is going to end in perpetual babble. Reset.

			 */

			cmd->error = -EOVERFLOW;	/* A cheap trick... */

		} else {

			ub_state_stat(sc, cmd);

			return;

		}

		if (urb->status != 0)

			goto Bad_End;

		}



		cmd->act_len = urb->actual_length;

		cmd->act_len += urb->actual_length;

		ub_cmdtr_act_len(sc, cmd);



		if (++cmd->current_sg < cmd->nsg) {

			ub_data_start(sc, cmd);

			return;

		}

		ub_state_stat(sc, cmd);



	} else if (cmd->state == UB_CMDST_STAT) {
@@ -1467,6 +1375,46 @@ Bad_End: /* Little Excel is dead */ 
	ub_state_done(sc, cmd, -EIO);

}



/*

 * Factorization helper for the command state machine:

 * Initiate a data segment transfer.

 */

static void ub_data_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)

{

	struct scatterlist *sg = &cmd->sgv[cmd->current_sg];

	int pipe;

	int rc;



	UB_INIT_COMPLETION(sc->work_done);



	if (cmd->dir == UB_DIR_READ)

		pipe = sc->recv_bulk_pipe;

	else

		pipe = sc->send_bulk_pipe;

	sc->last_pipe = pipe;

	usb_fill_bulk_urb(&sc->work_urb, sc->dev, pipe,

	    page_address(sg->page) + sg->offset, sg->length,

	    ub_urb_complete, sc);

	sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;

	sc->work_urb.actual_length = 0;

	sc->work_urb.error_count = 0;

	sc->work_urb.status = 0;



	if ((rc = usb_submit_urb(&sc->work_urb, GFP_ATOMIC)) != 0) {

		/* XXX Clear stalls */

		printk("ub: data #%d submit failed (%d)\n", cmd->tag, rc); /* P3 */

		ub_complete(&sc->work_done);

		ub_state_done(sc, cmd, rc);

		return;

	}



	sc->work_timer.expires = jiffies + UB_DATA_TIMEOUT;

	add_timer(&sc->work_timer);



	cmd->state = UB_CMDST_DATA;

	ub_cmdtr_state(sc, cmd);

}



/*

 * Factorization helper for the command state machine:

 * Finish the command.
@@ -1552,6 +1500,7 @@ static void ub_state_stat_counted(struct ub_dev *sc, struct ub_scsi_cmd *cmd) 
static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd)

{

	struct ub_scsi_cmd *scmd;

	struct scatterlist *sg;

	int rc;



	if (cmd->cdb[0] == REQUEST_SENSE) {
@@ -1560,12 +1509,17 @@ static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd) 
	}



	scmd = &sc->top_rqs_cmd;

	memset(scmd, 0, sizeof(struct ub_scsi_cmd));

	scmd->cdb[0] = REQUEST_SENSE;

	scmd->cdb[4] = UB_SENSE_SIZE;

	scmd->cdb_len = 6;

	scmd->dir = UB_DIR_READ;

	scmd->state = UB_CMDST_INIT;

	scmd->data = sc->top_sense;

	scmd->nsg = 1;

	sg = &scmd->sgv[0];

	sg->page = virt_to_page(sc->top_sense);

	sg->offset = (unsigned int)sc->top_sense & (PAGE_SIZE-1);

	sg->length = UB_SENSE_SIZE;

	scmd->len = UB_SENSE_SIZE;

	scmd->lun = cmd->lun;

	scmd->done = ub_top_sense_done;
@@ -1628,7 +1582,7 @@ static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd, 
 */

static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd)

{

	unsigned char *sense = scmd->data;

	unsigned char *sense = sc->top_sense;

	struct ub_scsi_cmd *cmd;



	/*
@@ -1920,6 +1874,7 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun, 
    struct ub_capacity *ret)

{

	struct ub_scsi_cmd *cmd;

	struct scatterlist *sg;

	char *p;

	enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };

	unsigned long flags;
@@ -1940,7 +1895,11 @@ static int ub_sync_read_cap(struct ub_dev *sc, struct ub_lun *lun, 
	cmd->cdb_len = 10;

	cmd->dir = UB_DIR_READ;

	cmd->state = UB_CMDST_INIT;

	cmd->data = p;

	cmd->nsg = 1;

	sg = &cmd->sgv[0];

	sg->page = virt_to_page(p);

	sg->offset = (unsigned int)p & (PAGE_SIZE-1);

	sg->length = 8;

	cmd->len = 8;

	cmd->lun = lun;

	cmd->done = ub_probe_done;

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