[PATCH] USB: ub 4: Zaitcev's quasi-S/G
authorPete Zaitcev <zaitcev@redhat.com>
Mon, 15 Aug 2005 04:16:03 +0000 (21:16 -0700)
committerGreg Kroah-Hartman <gregkh@suse.de>
Thu, 8 Sep 2005 23:22:40 +0000 (16:22 -0700)
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: Pete Zaitcev <zaitcev@yahoo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
drivers/block/ub.c

index 692553270401028c954aa73baf2b804ac40d9120..57d3279a881511295f3120b410f4519206b61dff 100644 (file)
@@ -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;
-
-       urq->rq = rq;
-       urq->current_sg = 0;
-       urq->dir = ub_dir;
+       block = rq->sector >> lun->capacity.bshift;
+       nblks = rq->nr_sectors >> lun->capacity.bshift;
 
-       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;
+
        }
-       cmd->data = rq->data;
+
+       /*
+        * 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;
+       }
+       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;
@@ -940,33 +903,32 @@ 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 (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)
+       if (cmd->error == 0) {
                uptodate = 1;
-       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;
+               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;
-       }
 
-       urq->rq = NULL;
+               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 (sc->top_sense[0] != 0)
+                               rq->errors = SAM_STAT_CHECK_CONDITION;
+                       else
+                               rq->errors = DID_ERROR << 16;
+               }
+       }
 
        ub_put_cmd(lun, cmd);
        ub_end_rq(rq, uptodate);
@@ -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 {
-                       if (urb->status != 0)
-                               goto Bad_End;
+                       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;