Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 2215 insertions, 0 deletions

diff --git a/drivers/block/ub.c b/drivers/block/ub.c
new file mode 100644
index 00000000000..ce42889f98f
--- /dev/null
+++ b/drivers/block/ub.c
@@ -0,0 +1,2215 @@
+/*
+ * The low performance USB storage driver (ub).
+ *
+ * Copyright (c) 1999, 2000 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
+ * Copyright (C) 2004 Pete Zaitcev (zaitcev@yahoo.com)
+ *
+ * This work is a part of Linux kernel, is derived from it,
+ * and is not licensed separately. See file COPYING for details.
+ *
+ * TODO (sorted by decreasing priority)
+ *  -- Do resets with usb_device_reset (needs a thread context, use khubd)
+ *  -- set readonly flag for CDs, set removable flag for CF readers
+ *  -- do inquiry and verify we got a disk and not a tape (for LUN mismatch)
+ *  -- support pphaneuf's SDDR-75 with two LUNs (also broken capacity...)
+ *  -- special case some senses, e.g. 3a/0 -> no media present, reduce retries
+ *  -- verify the 13 conditions and do bulk resets
+ *  -- normal pool of commands instead of cmdv[]?
+ *  -- kill last_pipe and simply do two-state clearing on both pipes
+ *  -- verify protocol (bulk) from USB descriptors (maybe...)
+ *  -- highmem and sg
+ *  -- move top_sense and work_bcs into separate allocations (if they survive)
+ *     for cache purists and esoteric architectures.
+ *  -- prune comments, they are too volumnous
+ *  -- Exterminate P3 printks
+ *  -- Resove XXX's
+ *  -- Redo "benh's retries", perhaps have spin-up code to handle them. V:D=?
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/usb.h>
+#include <linux/blkdev.h>
+#include <linux/devfs_fs_kernel.h>
+#include <linux/timer.h>
+#include <scsi/scsi.h>
+
+#define DRV_NAME "ub"
+#define DEVFS_NAME DRV_NAME
+
+#define UB_MAJOR 180
+
+/*
+ * Definitions which have to be scattered once we understand the layout better.
+ */
+
+/* Transport (despite PR in the name) */
+#define US_PR_BULK	0x50		/* bulk only */
+
+/* Protocol */
+#define US_SC_SCSI	0x06		/* Transparent */
+
+/*
+ */
+#define UB_MINORS_PER_MAJOR	8
+
+#define UB_MAX_CDB_SIZE      16		/* Corresponds to Bulk */
+
+#define UB_SENSE_SIZE  18
+
+/*
+ */
+
+/* command block wrapper */
+struct bulk_cb_wrap {
+	__le32	Signature;		/* contains 'USBC' */
+	u32	Tag;			/* unique per command id */
+	__le32	DataTransferLength;	/* size of data */
+	u8	Flags;			/* direction in bit 0 */
+	u8	Lun;			/* LUN normally 0 */
+	u8	Length;			/* of of the CDB */
+	u8	CDB[UB_MAX_CDB_SIZE];	/* max command */
+};
+
+#define US_BULK_CB_WRAP_LEN	31
+#define US_BULK_CB_SIGN		0x43425355	/*spells out USBC */
+#define US_BULK_FLAG_IN		1
+#define US_BULK_FLAG_OUT	0
+
+/* command status wrapper */
+struct bulk_cs_wrap {
+	__le32	Signature;		/* should = 'USBS' */
+	u32	Tag;			/* same as original command */
+	__le32	Residue;		/* amount not transferred */
+	u8	Status;			/* see below */
+};
+
+#define US_BULK_CS_WRAP_LEN	13
+#define US_BULK_CS_SIGN		0x53425355	/* spells out 'USBS' */
+/* This is for Olympus Camedia digital cameras */
+#define US_BULK_CS_OLYMPUS_SIGN	0x55425355	/* spells out 'USBU' */
+#define US_BULK_STAT_OK		0
+#define US_BULK_STAT_FAIL	1
+#define US_BULK_STAT_PHASE	2
+
+/* bulk-only class specific requests */
+#define US_BULK_RESET_REQUEST	0xff
+#define US_BULK_GET_MAX_LUN	0xfe
+
+/*
+ */
+struct ub_dev;
+
+#define UB_MAX_REQ_SG	1
+#define UB_MAX_SECTORS 64
+
+/*
+ * A second is more than enough for a 32K transfer (UB_MAX_SECTORS)
+ * even if a webcam hogs the bus, but some devices need time to spin up.
+ */
+#define UB_URB_TIMEOUT	(HZ*2)
+#define UB_DATA_TIMEOUT	(HZ*5)	/* ZIP does spin-ups in the data phase */
+#define UB_STAT_TIMEOUT	(HZ*5)	/* Same spinups and eject for a dataless cmd. */
+#define UB_CTRL_TIMEOUT	(HZ/2)	/* 500ms ought to be enough to clear a stall */
+
+/*
+ * An instance of a SCSI command in transit.
+ */
+#define UB_DIR_NONE	0
+#define UB_DIR_READ	1
+#define UB_DIR_ILLEGAL2	2
+#define UB_DIR_WRITE	3
+
+#define UB_DIR_CHAR(c)  (((c)==UB_DIR_WRITE)? 'w': \
+			 (((c)==UB_DIR_READ)? 'r': 'n'))
+
+enum ub_scsi_cmd_state {
+	UB_CMDST_INIT,			/* Initial state */
+	UB_CMDST_CMD,			/* Command submitted */
+	UB_CMDST_DATA,			/* Data phase */
+	UB_CMDST_CLR2STS,		/* Clearing before requesting status */
+	UB_CMDST_STAT,			/* Status phase */
+	UB_CMDST_CLEAR,			/* Clearing a stall (halt, actually) */
+	UB_CMDST_SENSE,			/* Sending Request Sense */
+	UB_CMDST_DONE			/* Final state */
+};
+
+static char *ub_scsi_cmd_stname[] = {
+	".  ",
+	"Cmd",
+	"dat",
+	"c2s",
+	"sts",
+	"clr",
+	"Sen",
+	"fin"
+};
+
+struct ub_scsi_cmd {
+	unsigned char cdb[UB_MAX_CDB_SIZE];
+	unsigned char cdb_len;
+
+	unsigned char dir;		/* 0 - none, 1 - read, 3 - write. */
+	unsigned char trace_index;
+	enum ub_scsi_cmd_state state;
+	unsigned int tag;
+	struct ub_scsi_cmd *next;
+
+	int error;			/* Return code - valid upon done */
+	unsigned int act_len;		/* Return size */
+	unsigned char key, asc, ascq;	/* May be valid if error==-EIO */
+
+	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 */
+	// struct scatterlist sgv[UB_MAX_REQ_SG];
+
+	void (*done)(struct ub_dev *, struct ub_scsi_cmd *);
+	void *back;
+};
+
+/*
+ */
+struct ub_capacity {
+	unsigned long nsec;		/* Linux size - 512 byte sectors */
+	unsigned int bsize;		/* Linux hardsect_size */
+	unsigned int bshift;		/* Shift between 512 and hard sects */
+};
+
+/*
+ * The SCSI command tracing structure.
+ */
+
+#define SCMD_ST_HIST_SZ   8
+#define SCMD_TRACE_SZ    63		/* Less than 4KB of 61-byte lines */
+
+struct ub_scsi_cmd_trace {
+	int hcur;
+	unsigned int tag;
+	unsigned int req_size, act_size;
+	unsigned char op;
+	unsigned char dir;
+	unsigned char key, asc, ascq;
+	char st_hst[SCMD_ST_HIST_SZ];	
+};
+
+struct ub_scsi_trace {
+	int cur;
+	struct ub_scsi_cmd_trace vec[SCMD_TRACE_SZ];
+};
+
+/*
+ * This is a direct take-off from linux/include/completion.h
+ * The difference is that I do not wait on this thing, just poll.
+ * When I want to wait (ub_probe), I just use the stock completion.
+ *
+ * Note that INIT_COMPLETION takes no lock. It is correct. But why
+ * in the bloody hell that thing takes struct instead of pointer to struct
+ * is quite beyond me. I just copied it from the stock completion.
+ */
+struct ub_completion {
+	unsigned int done;
+	spinlock_t lock;
+};
+
+static inline void ub_init_completion(struct ub_completion *x)
+{
+	x->done = 0;
+	spin_lock_init(&x->lock);
+}
+
+#define UB_INIT_COMPLETION(x)	((x).done = 0)
+
+static void ub_complete(struct ub_completion *x)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&x->lock, flags);
+	x->done++;
+	spin_unlock_irqrestore(&x->lock, flags);
+}
+
+static int ub_is_completed(struct ub_completion *x)
+{
+	unsigned long flags;
+	int ret;
+
+	spin_lock_irqsave(&x->lock, flags);
+	ret = x->done;
+	spin_unlock_irqrestore(&x->lock, flags);
+	return ret;
+}
+
+/*
+ */
+struct ub_scsi_cmd_queue {
+	int qlen, qmax;
+	struct ub_scsi_cmd *head, *tail;
+};
+
+/*
+ * The UB device instance.
+ */
+struct ub_dev {
+	spinlock_t lock;
+	int id;				/* Number among ub's */
+	atomic_t poison;		/* The USB device is disconnected */
+	int openc;			/* protected by ub_lock! */
+					/* kref is too implicit for our taste */
+	unsigned int tagcnt;
+	int changed;			/* Media was changed */
+	int removable;
+	int readonly;
+	int first_open;			/* Kludge. See ub_bd_open. */
+	char name[8];
+	struct usb_device *dev;
+	struct usb_interface *intf;
+
+	struct ub_capacity capacity; 
+	struct gendisk *disk;
+
+	unsigned int send_bulk_pipe;	/* cached pipe values */
+	unsigned int recv_bulk_pipe;
+	unsigned int send_ctrl_pipe;
+	unsigned int recv_ctrl_pipe;
+
+	struct tasklet_struct tasklet;
+
+	/* XXX Use Ingo's mempool (once we have more than one) */
+	int cmda[1];
+	struct ub_scsi_cmd cmdv[1];
+
+	struct ub_scsi_cmd_queue cmd_queue;
+	struct ub_scsi_cmd top_rqs_cmd;	/* REQUEST SENSE */
+	unsigned char top_sense[UB_SENSE_SIZE];
+
+	struct ub_completion work_done;
+	struct urb work_urb;
+	struct timer_list work_timer;
+	int last_pipe;			/* What might need clearing */
+	struct bulk_cb_wrap work_bcb;
+	struct bulk_cs_wrap work_bcs;
+	struct usb_ctrlrequest work_cr;
+
+	struct ub_scsi_trace tr;
+};
+
+/*
+ */
+static void ub_cleanup(struct ub_dev *sc);
+static int ub_bd_rq_fn_1(struct ub_dev *sc, struct request *rq);
+static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
+    struct request *rq);
+static int ub_cmd_build_packet(struct ub_dev *sc, 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_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_state_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd, int rc);
+static void __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);
+static void ub_state_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd);
+static int ub_submit_clear_stall(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
+    int stalled_pipe);
+static void ub_top_sense_done(struct ub_dev *sc, struct ub_scsi_cmd *scmd);
+static int ub_sync_tur(struct ub_dev *sc);
+static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret);
+
+/*
+ */
+static struct usb_device_id ub_usb_ids[] = {
+	// { USB_DEVICE_VER(0x0781, 0x0002, 0x0009, 0x0009) },	/* SDDR-31 */
+	{ USB_INTERFACE_INFO(USB_CLASS_MASS_STORAGE, US_SC_SCSI, US_PR_BULK) },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(usb, ub_usb_ids);
+
+/*
+ * Find me a way to identify "next free minor" for add_disk(),
+ * and the array disappears the next day. However, the number of
+ * hosts has something to do with the naming and /proc/partitions.
+ * This has to be thought out in detail before changing.
+ * If UB_MAX_HOST was 1000, we'd use a bitmap. Or a better data structure.
+ */
+#define UB_MAX_HOSTS  26
+static char ub_hostv[UB_MAX_HOSTS];
+static DEFINE_SPINLOCK(ub_lock);	/* Locks globals and ->openc */
+
+/*
+ * The SCSI command tracing procedures.
+ */
+
+static void ub_cmdtr_new(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	int n;
+	struct ub_scsi_cmd_trace *t;
+
+	if ((n = sc->tr.cur + 1) == SCMD_TRACE_SZ) n = 0;
+	t = &sc->tr.vec[n];
+
+	memset(t, 0, sizeof(struct ub_scsi_cmd_trace));
+	t->tag = cmd->tag;
+	t->op = cmd->cdb[0];
+	t->dir = cmd->dir;
+	t->req_size = cmd->len;
+	t->st_hst[0] = cmd->state;
+
+	sc->tr.cur = n;
+	cmd->trace_index = n;
+}
+
+static void ub_cmdtr_state(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	int n;
+	struct ub_scsi_cmd_trace *t;
+
+	t = &sc->tr.vec[cmd->trace_index];
+	if (t->tag == cmd->tag) {
+		if ((n = t->hcur + 1) == SCMD_ST_HIST_SZ) n = 0;
+		t->st_hst[n] = cmd->state;
+		t->hcur = n;
+	}
+}
+
+static void ub_cmdtr_act_len(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	struct ub_scsi_cmd_trace *t;
+
+	t = &sc->tr.vec[cmd->trace_index];
+	if (t->tag == cmd->tag)
+		t->act_size = cmd->act_len;
+}
+
+static void ub_cmdtr_sense(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
+    unsigned char *sense)
+{
+	struct ub_scsi_cmd_trace *t;
+
+	t = &sc->tr.vec[cmd->trace_index];
+	if (t->tag == cmd->tag) {
+		t->key = sense[2] & 0x0F;
+		t->asc = sense[12];
+		t->ascq = sense[13];
+	}
+}
+
+static ssize_t ub_diag_show(struct device *dev, char *page)
+{
+	struct usb_interface *intf;
+	struct ub_dev *sc;
+	int cnt;
+	unsigned long flags;
+	int nc, nh;
+	int i, j;
+	struct ub_scsi_cmd_trace *t;
+
+	intf = to_usb_interface(dev);
+	sc = usb_get_intfdata(intf);
+	if (sc == NULL)
+		return 0;
+
+	cnt = 0;
+	spin_lock_irqsave(&sc->lock, flags);
+
+	cnt += sprintf(page + cnt,
+	    "qlen %d qmax %d changed %d removable %d readonly %d\n",
+	    sc->cmd_queue.qlen, sc->cmd_queue.qmax,
+	    sc->changed, sc->removable, sc->readonly);
+
+	if ((nc = sc->tr.cur + 1) == SCMD_TRACE_SZ) nc = 0;
+	for (j = 0; j < SCMD_TRACE_SZ; j++) {
+		t = &sc->tr.vec[nc];
+
+		cnt += sprintf(page + cnt, "%08x %02x", t->tag, t->op);
+		if (t->op == REQUEST_SENSE) {
+			cnt += sprintf(page + cnt, " [sense %x %02x %02x]",
+					t->key, t->asc, t->ascq);
+		} else {
+			cnt += sprintf(page + cnt, " %c", UB_DIR_CHAR(t->dir));
+			cnt += sprintf(page + cnt, " [%5d %5d]",
+					t->req_size, t->act_size);
+		}
+		if ((nh = t->hcur + 1) == SCMD_ST_HIST_SZ) nh = 0;
+		for (i = 0; i < SCMD_ST_HIST_SZ; i++) {
+			cnt += sprintf(page + cnt, " %s",
+					ub_scsi_cmd_stname[(int)t->st_hst[nh]]);
+			if (++nh == SCMD_ST_HIST_SZ) nh = 0;
+		}
+		cnt += sprintf(page + cnt, "\n");
+
+		if (++nc == SCMD_TRACE_SZ) nc = 0;
+	}
+
+	spin_unlock_irqrestore(&sc->lock, flags);
+	return cnt;
+}
+
+static DEVICE_ATTR(diag, S_IRUGO, ub_diag_show, NULL); /* N.B. World readable */
+
+/*
+ * The id allocator.
+ *
+ * This also stores the host for indexing by minor, which is somewhat dirty.
+ */
+static int ub_id_get(void)
+{
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&ub_lock, flags);
+	for (i = 0; i < UB_MAX_HOSTS; i++) {
+		if (ub_hostv[i] == 0) {
+			ub_hostv[i] = 1;
+			spin_unlock_irqrestore(&ub_lock, flags);
+			return i;
+		}
+	}
+	spin_unlock_irqrestore(&ub_lock, flags);
+	return -1;
+}
+
+static void ub_id_put(int id)
+{
+	unsigned long flags;
+
+	if (id < 0 || id >= UB_MAX_HOSTS) {
+		printk(KERN_ERR DRV_NAME ": bad host ID %d\n", id);
+		return;
+	}
+
+	spin_lock_irqsave(&ub_lock, flags);
+	if (ub_hostv[id] == 0) {
+		spin_unlock_irqrestore(&ub_lock, flags);
+		printk(KERN_ERR DRV_NAME ": freeing free host ID %d\n", id);
+		return;
+	}
+	ub_hostv[id] = 0;
+	spin_unlock_irqrestore(&ub_lock, flags);
+}
+
+/*
+ * Downcount for deallocation. This rides on two assumptions:
+ *  - once something is poisoned, its refcount cannot grow
+ *  - opens cannot happen at this time (del_gendisk was done)
+ * If the above is true, we can drop the lock, which we need for
+ * blk_cleanup_queue(): the silly thing may attempt to sleep.
+ * [Actually, it never needs to sleep for us, but it calls might_sleep()]
+ */
+static void ub_put(struct ub_dev *sc)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ub_lock, flags);
+	--sc->openc;
+	if (sc->openc == 0 && atomic_read(&sc->poison)) {
+		spin_unlock_irqrestore(&ub_lock, flags);
+		ub_cleanup(sc);
+	} else {
+		spin_unlock_irqrestore(&ub_lock, flags);
+	}
+}
+
+/*
+ * Final cleanup and deallocation.
+ */
+static void ub_cleanup(struct ub_dev *sc)
+{
+	request_queue_t *q;
+
+	/* I don't think queue can be NULL. But... Stolen from sx8.c */
+	if ((q = sc->disk->queue) != NULL)
+		blk_cleanup_queue(q);
+
+	/*
+	 * If we zero disk->private_data BEFORE put_disk, we have to check
+	 * for NULL all over the place in open, release, check_media and
+	 * revalidate, because the block level semaphore is well inside the
+	 * put_disk. But we cannot zero after the call, because *disk is gone.
+	 * The sd.c is blatantly racy in this area.
+	 */
+	/* disk->private_data = NULL; */
+	put_disk(sc->disk);
+	sc->disk = NULL;
+
+	ub_id_put(sc->id);
+	kfree(sc);
+}
+
+/*
+ * The "command allocator".
+ */
+static struct ub_scsi_cmd *ub_get_cmd(struct ub_dev *sc)
+{
+	struct ub_scsi_cmd *ret;
+
+	if (sc->cmda[0])
+		return NULL;
+	ret = &sc->cmdv[0];
+	sc->cmda[0] = 1;
+	return ret;
+}
+
+static void ub_put_cmd(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	if (cmd != &sc->cmdv[0]) {
+		printk(KERN_WARNING "%s: releasing a foreign cmd %p\n",
+		    sc->name, cmd);
+		return;
+	}
+	if (!sc->cmda[0]) {
+		printk(KERN_WARNING "%s: releasing a free cmd\n", sc->name);
+		return;
+	}
+	sc->cmda[0] = 0;
+}
+
+/*
+ * The command queue.
+ */
+static void ub_cmdq_add(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
+
+	if (t->qlen++ == 0) {
+		t->head = cmd;
+		t->tail = cmd;
+	} else {
+		t->tail->next = cmd;
+		t->tail = cmd;
+	}
+
+	if (t->qlen > t->qmax)
+		t->qmax = t->qlen;
+}
+
+static void ub_cmdq_insert(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
+
+	if (t->qlen++ == 0) {
+		t->head = cmd;
+		t->tail = cmd;
+	} else {
+		cmd->next = t->head;
+		t->head = cmd;
+	}
+
+	if (t->qlen > t->qmax)
+		t->qmax = t->qlen;
+}
+
+static struct ub_scsi_cmd *ub_cmdq_pop(struct ub_dev *sc)
+{
+	struct ub_scsi_cmd_queue *t = &sc->cmd_queue;
+	struct ub_scsi_cmd *cmd;
+
+	if (t->qlen == 0)
+		return NULL;
+	if (--t->qlen == 0)
+		t->tail = NULL;
+	cmd = t->head;
+	t->head = cmd->next;
+	cmd->next = NULL;
+	return cmd;
+}
+
+#define ub_cmdq_peek(sc)  ((sc)->cmd_queue.head)
+
+/*
+ * The request function is our main entry point
+ */
+
+static void ub_bd_rq_fn(request_queue_t *q)
+{
+	struct ub_dev *sc = q->queuedata;
+	struct request *rq;
+
+	while ((rq = elv_next_request(q)) != NULL) {
+		if (ub_bd_rq_fn_1(sc, rq) != 0) {
+			blk_stop_queue(q);
+			break;
+		}
+	}
+}
+
+static int ub_bd_rq_fn_1(struct ub_dev *sc, struct request *rq)
+{
+	struct ub_scsi_cmd *cmd;
+	int rc;
+
+	if (atomic_read(&sc->poison) || sc->changed) {
+		blkdev_dequeue_request(rq);
+		ub_end_rq(rq, 0);
+		return 0;
+	}
+
+	if ((cmd = ub_get_cmd(sc)) == NULL)
+		return -1;
+	memset(cmd, 0, sizeof(struct ub_scsi_cmd));
+
+	blkdev_dequeue_request(rq);
+
+	if (blk_pc_request(rq)) {
+		rc = ub_cmd_build_packet(sc, cmd, rq);
+	} else {
+		rc = ub_cmd_build_block(sc, cmd, rq);
+	}
+	if (rc != 0) {
+		ub_put_cmd(sc, cmd);
+		ub_end_rq(rq, 0);
+		blk_start_queue(sc->disk->queue);
+		return 0;
+	}
+
+	cmd->state = UB_CMDST_INIT;
+	cmd->done = ub_rw_cmd_done;
+	cmd->back = rq;
+
+	cmd->tag = sc->tagcnt++;
+	if ((rc = ub_submit_scsi(sc, cmd)) != 0) {
+		ub_put_cmd(sc, cmd);
+		ub_end_rq(rq, 0);
+		blk_start_queue(sc->disk->queue);
+		return 0;
+	}
+
+	return 0;
+}
+
+static int ub_cmd_build_block(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
+    struct request *rq)
+{
+	int ub_dir;
+#if 0 /* We use rq->buffer for now */
+	struct scatterlist *sg;
+	int n_elem;
+#endif
+	unsigned int block, nblks;
+
+	if (rq_data_dir(rq) == WRITE)
+		ub_dir = UB_DIR_WRITE;
+	else
+		ub_dir = UB_DIR_READ;
+
+	/*
+	 * get scatterlist from block layer
+	 */
+#if 0 /* We use rq->buffer for now */
+	sg = &cmd->sgv[0];
+	n_elem = blk_rq_map_sg(q, rq, sg);
+	if (n_elem <= 0) {
+		ub_put_cmd(sc, cmd);
+		ub_end_rq(rq, 0);
+		blk_start_queue(q);
+		return 0;		/* request with no s/g entries? */
+	}
+
+	if (n_elem != 1) {		/* Paranoia */
+		printk(KERN_WARNING "%s: request with %d segments\n",
+		    sc->name, n_elem);
+		ub_put_cmd(sc, cmd);
+		ub_end_rq(rq, 0);
+		blk_start_queue(q);
+		return 0;
+	}
+#endif
+
+	/*
+	 * XXX Unfortunately, this check does not work. It is quite possible
+	 * to get bogus non-null rq->buffer if you allow sg by mistake.
+	 */
+	if (rq->buffer == NULL) {
+		/*
+		 * This must not happen if we set the queue right.
+		 * The block level must create bounce buffers for us.
+		 */
+		static int do_print = 1;
+		if (do_print) {
+			printk(KERN_WARNING "%s: unmapped block request"
+			    " flags 0x%lx sectors %lu\n",
+			    sc->name, rq->flags, rq->nr_sectors);
+			do_print = 0;
+		}
+		return -1;
+	}
+
+	/*
+	 * build the command
+	 *
+	 * The call to blk_queue_hardsect_size() guarantees that request
+	 * is aligned, but it is given in terms of 512 byte units, always.
+	 */
+	block = rq->sector >> sc->capacity.bshift;
+	nblks = rq->nr_sectors >> sc->capacity.bshift;
+
+	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;
+	cmd->cdb[4] = block >> 8;
+	cmd->cdb[5] = block;
+	cmd->cdb[7] = nblks >> 8;
+	cmd->cdb[8] = nblks;
+	cmd->cdb_len = 10;
+
+	cmd->dir = ub_dir;
+	cmd->data = rq->buffer;
+	cmd->len = rq->nr_sectors * 512;
+
+	return 0;
+}
+
+static int ub_cmd_build_packet(struct ub_dev *sc, struct ub_scsi_cmd *cmd,
+    struct request *rq)
+{
+
+	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;
+
+	if (rq->data_len == 0) {
+		cmd->dir = UB_DIR_NONE;
+	} else {
+		if (rq_data_dir(rq) == WRITE)
+			cmd->dir = UB_DIR_WRITE;
+		else
+			cmd->dir = UB_DIR_READ;
+	}
+	cmd->data = rq->data;
+	cmd->len = rq->data_len;
+
+	return 0;
+}
+
+static void ub_rw_cmd_done(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	struct request *rq = cmd->back;
+	struct gendisk *disk = sc->disk;
+	request_queue_t *q = disk->queue;
+	int uptodate;
+
+	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;
+	else
+		uptodate = 0;
+
+	ub_put_cmd(sc, cmd);
+	ub_end_rq(rq, uptodate);
+	blk_start_queue(q);
+}
+
+static void ub_end_rq(struct request *rq, int uptodate)
+{
+	int rc;
+
+	rc = end_that_request_first(rq, uptodate, rq->hard_nr_sectors);
+	// assert(rc == 0);
+	end_that_request_last(rq);
+}
+
+/*
+ * Submit a regular SCSI operation (not an auto-sense).
+ *
+ * The Iron Law of Good Submit Routine is:
+ * Zero return - callback is done, Nonzero return - callback is not done.
+ * No exceptions.
+ *
+ * Host is assumed locked.
+ *
+ * XXX We only support Bulk for the moment.
+ */
+static int ub_submit_scsi(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+
+	if (cmd->state != UB_CMDST_INIT ||
+	    (cmd->dir != UB_DIR_NONE && cmd->len == 0)) {
+		return -EINVAL;
+	}
+
+	ub_cmdq_add(sc, cmd);
+	/*
+	 * We can call ub_scsi_dispatch(sc) right away here, but it's a little
+	 * safer to jump to a tasklet, in case upper layers do something silly.
+	 */
+	tasklet_schedule(&sc->tasklet);
+	return 0;
+}
+
+/*
+ * Submit the first URB for the queued command.
+ * This function does not deal with queueing in any way.
+ */
+static int ub_scsi_cmd_start(struct ub_dev *sc, struct ub_scsi_cmd *cmd)
+{
+	struct bulk_cb_wrap *bcb;
+	int rc;
+
+	bcb = &sc->work_bcb;
+
+	/*
+	 * ``If the allocation length is eighteen or greater, and a device
+	 * server returns less than eithteen bytes of data, the application
+	 * client should assume that the bytes not transferred would have been
+	 * zeroes had the device server returned those bytes.''
+	 *
+	 * We zero sense for all commands so that when a packet request
+	 * fails it does not return a stale sense.
+	 */
+	memset(&sc->top_sense, 0, UB_SENSE_SIZE);
+
+	/* set up the command wrapper */
+	bcb->Signature = cpu_to_le32(US_BULK_CB_SIGN);
+	bcb->Tag = cmd->tag;		/* Endianness is not important */
+	bcb->DataTransferLength = cpu_to_le32(cmd->len);
+	bcb->Flags = (cmd->dir == UB_DIR_READ) ? 0x80 : 0;
+	bcb->Lun = 0;			/* No multi-LUN yet */
+	bcb->Length = cmd->cdb_len;
+
+	/* copy the command payload */
+	memcpy(bcb->CDB, cmd->cdb, UB_MAX_CDB_SIZE);
+
+	UB_INIT_COMPLETION(sc->work_done);
+
+	sc->last_pipe = sc->send_bulk_pipe;
+	usb_fill_bulk_urb(&sc->work_urb, sc->dev, sc->send_bulk_pipe,
+	    bcb, US_BULK_CB_WRAP_LEN, ub_urb_complete, sc);
+	sc->work_urb.transfer_flags = URB_ASYNC_UNLINK;
+
+	/* Fill what we shouldn't be filling, because usb-storage did so. */
+	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: cmd #%d start failed (%d)\n", cmd->tag, rc); /* P3 */
+		ub_complete(&sc->work_done);
+		return rc;
+	}
+
+	sc->work_timer.expires = jiffies + UB_URB_TIMEOUT;
+	add_timer(&sc->work_timer);
+
+	cmd->state = UB_CMDST_CMD;
+	ub_cmdtr_state(sc, cmd);
+	return 0;
+}
+
+/*
+ * Timeout handler.
+ */
+static void ub_urb_timeout(unsigned long arg)
+{
+	struct ub_dev *sc = (struct ub_dev *) arg;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sc->lock, flags);
+	usb_unlink_urb(&sc->work_urb);
+	spin_unlock_irqrestore(&sc->lock, flags);
+}
+
+/*
+ * Completion routine for the work URB.
+ *
+ * This can be called directly from usb_submit_urb (while we have
+ * the sc->lock taken) and from an interrupt (while we do NOT have
+ * the sc->lock taken). Therefore, bounce this off to a tasklet.
+ */
+static void ub_urb_complete(struct urb *urb, struct pt_regs *pt)
+{
+	struct ub_dev *sc = urb->context;
+
+	ub_complete(&sc->work_done);
+	tasklet_schedule(&sc->tasklet);
+}
+
+static void ub_scsi_action(unsigned long _dev)
+{
+	struct ub_dev *sc = (struct ub_dev *) _dev;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sc->lock, flags);
+	del_timer(&sc->work_timer);
+	ub_scsi_dispatch(sc);
+	spin_unlock_irqrestore(&sc->lock, flags);
+}
+
+static void ub_scsi_dispatch(struct ub_dev *sc)
+{
+	struct ub_scsi_cmd *cmd;
+	int rc;
+
+	while ((cmd = ub_cmdq_peek(sc)) != NULL) {
+		if (cmd->state == UB_CMDST_DONE) {
+			ub_cmdq_pop(sc);
+			(*cmd->done)(sc, cmd);
+		} else if (cmd->state == UB_CMDST_INIT) {
+			ub_cmdtr_new(sc, cmd);
+			if ((rc = ub_scsi_cmd_start(sc, cmd)) == 0)
+				break;
+			cmd->error = rc;
+			cmd->state = UB_CMDST_DONE;
+			ub_cmdtr_state(sc, cmd);
+		} else {
+			if (!ub_is_completed(&sc->work_done))
+				break;
+			ub_scsi_urb_compl(sc, cmd);
+		}
+	}
+}
+
+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)) {
+		/* A little too simplistic, I feel... */
+		goto Bad_End;
+	}
+
+	if (cmd->state == UB_CMDST_CLEAR) {
+		if (urb->status == -EPIPE) {
+			/*
+			 * STALL while clearning STALL.
+			 * The control pipe clears itself - nothing to do.
+			 * XXX Might try to reset the device here and retry.
+			 */
+			printk(KERN_NOTICE "%s: "
+			    "stall on control pipe for device %u\n",
+			    sc->name, sc->dev->devnum);
+			goto Bad_End;
+		}
+
+		/*
+		 * We ignore the result for the halt clear.
+		 */
+
+		/* reset the endpoint toggle */
+		usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
+			usb_pipeout(sc->last_pipe), 0);
+
+		ub_state_sense(sc, cmd);
+
+	} else if (cmd->state == UB_CMDST_CLR2STS) {
+		if (urb->status == -EPIPE) {
+			/*
+			 * STALL while clearning STALL.
+			 * The control pipe clears itself - nothing to do.
+			 * XXX Might try to reset the device here and retry.
+			 */
+			printk(KERN_NOTICE "%s: "
+			    "stall on control pipe for device %u\n",
+			    sc->name, sc->dev->devnum);
+			goto Bad_End;
+		}
+
+		/*
+		 * We ignore the result for the halt clear.
+		 */
+
+		/* reset the endpoint toggle */
+		usb_settoggle(sc->dev, usb_pipeendpoint(sc->last_pipe),
+			usb_pipeout(sc->last_pipe), 0);
+
+		ub_state_stat(sc, cmd);
+
+	} else if (cmd->state == UB_CMDST_CMD) {
+		if (urb->status == -EPIPE) {
+			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
+			if (rc != 0) {
+				printk(KERN_NOTICE "%s: "
+				    "unable to submit clear for device %u"
+				    " (code %d)\n",
+				    sc->name, sc->dev->devnum, rc);
+				/*
+				 * This is typically ENOMEM or some other such shit.
+				 * Retrying is pointless. Just do Bad End on it...
+				 */
+				goto Bad_End;
+			}
+			cmd->state = UB_CMDST_CLEAR;
+			ub_cmdtr_state(sc, cmd);
+			return;
+		}
+		if (urb->status != 0) {
+			printk("ub: cmd #%d cmd status (%d)\n", cmd->tag, urb->status); /* P3 */
+			goto Bad_End;
+		}
+		if (urb->actual_length != US_BULK_CB_WRAP_LEN) {
+			printk("ub: cmd #%d xferred %d\n", cmd->tag, urb->actual_length); /* P3 */
+			/* XXX Must do reset here to unconfuse the device */
+			goto Bad_End;
+		}
+
+		if (cmd->dir == UB_DIR_NONE) {
+			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);
+
+	} else if (cmd->state == UB_CMDST_DATA) {
+		if (urb->status == -EPIPE) {
+			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
+			if (rc != 0) {
+				printk(KERN_NOTICE "%s: "
+				    "unable to submit clear for device %u"
+				    " (code %d)\n",
+				    sc->name, sc->dev->devnum, rc);
+				/*
+				 * This is typically ENOMEM or some other such shit.
+				 * Retrying is pointless. Just do Bad End on it...
+				 */
+				goto Bad_End;
+			}
+			cmd->state = UB_CMDST_CLR2STS;
+			ub_cmdtr_state(sc, cmd);
+			return;
+		}
+		if (urb->status == -EOVERFLOW) {
+			/*
+			 * A babble? Failure, but we must transfer CSW now.
+			 */
+			cmd->error = -EOVERFLOW;	/* A cheap trick... */
+		} else {
+			if (urb->status != 0)
+				goto Bad_End;
+		}
+
+		cmd->act_len = urb->actual_length;
+		ub_cmdtr_act_len(sc, cmd);
+
+		ub_state_stat(sc, cmd);
+
+	} else if (cmd->state == UB_CMDST_STAT) {
+		if (urb->status == -EPIPE) {
+			rc = ub_submit_clear_stall(sc, cmd, sc->last_pipe);
+			if (rc != 0) {
+				printk(KERN_NOTICE "%s: "
+				    "unable to submit clear for device %u"
+				    " (code %d)\n",
+				    sc->name, sc->dev->devnum, rc);
+				/*
+				 * This is typically ENOMEM or some other such shit.
+				 * Retrying is pointless. Just do Bad End on it...
+				 */
+				goto Bad_End;
+			}
+			cmd->state = UB_CMDST_CLEAR;
+			ub_cmdtr_state(sc, cmd);
+			return;
+		}
+		if (urb->status != 0)
+			goto Bad_End;
+
+		if (urb->actual_length == 0) {
+			/*
+			 * Some broken devices add unnecessary zero-length
+			 * packets to the end of their data transfers.
+			 * Such packets show up as 0-length CSWs. If we
+			 * encounter such a thing, try to read the CSW again.
+			 */
+			if (++cmd->stat_count >= 4) {
+				printk(KERN_NOTICE "%s: "
+				    "unable to get CSW on device %u\n",
+				    sc->name, sc->dev->devnum);
+				goto Bad_End;
+			}
+			__ub_state_stat(sc, cmd);
+			return;
+		}
+
+		/*
+		 * Check the returned Bulk protocol status.
+		 */
+
+		bcs = &sc->work_bcs;
+		rc = le32_to_cpu(bcs->Residue);
+		if (rc != cmd->len - cmd->act_len) {
+			/*
+			 * It is all right to transfer less, the caller has
+			 * to check. But it's not all right if the device
+			 * counts disagree with our counts.
+			 */
+			/* P3 */ printk("%s: resid %d len %d act %d\n",
+			    sc->name, rc, cmd->len, cmd->act_len);
+			goto Bad_End;
+		}
+</