[SCSI] remove aic7xxx busyq

The aic7xxx driver has two spurious queues in it's linux glue code: the
busyq which queues incoming commands to the driver and the completeq
which queues finished commands before sending them back to the mid-layer

This patch just removes the busyq and makes the aic finally return the
correct status to get the mid-layer to manage its queueing, so a command
is either committed to the sequencer or returned to the midlayer for
requeue.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

2 files changed, 191 insertions, 438 deletions

diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index 0ed9ccc3091e..9017942407d8 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -458,26 +458,20 @@ static struct ahc_linux_device*	ahc_linux_alloc_device(struct ahc_softc*,
                                                        u_int);
 static void                     ahc_linux_free_device(struct ahc_softc*,
                                                       struct ahc_linux_device*);
-static void ahc_linux_run_device_queue(struct ahc_softc*,
-                                       struct ahc_linux_device*);
+static int ahc_linux_run_command(struct ahc_softc*,
+                                 struct ahc_linux_device *,
+                                 struct scsi_cmnd *);
 static void ahc_linux_setup_tag_info_global(char *p);
 static aic_option_callback_t ahc_linux_setup_tag_info;
 static int  aic7xxx_setup(char *s);
 static int  ahc_linux_next_unit(void);
-static void ahc_runq_tasklet(unsigned long data);
 static struct ahc_cmd *ahc_linux_run_complete_queue(struct ahc_softc *ahc);
 
 /********************************* Inlines ************************************/
-static __inline void ahc_schedule_runq(struct ahc_softc *ahc);
 static __inline struct ahc_linux_device*
                      ahc_linux_get_device(struct ahc_softc *ahc, u_int channel,
                                           u_int target, u_int lun, int alloc);
 static __inline void ahc_schedule_completeq(struct ahc_softc *ahc);
-static __inline void ahc_linux_check_device_queue(struct ahc_softc *ahc,
-                                                  struct ahc_linux_device *dev);
-static __inline struct ahc_linux_device *
-                     ahc_linux_next_device_to_run(struct ahc_softc *ahc);
-static __inline void ahc_linux_run_device_queues(struct ahc_softc *ahc);
 static __inline void ahc_linux_unmap_scb(struct ahc_softc*, struct scb*);
 
 static __inline int ahc_linux_map_seg(struct ahc_softc *ahc, struct scb *scb,
@@ -494,15 +488,6 @@ ahc_schedule_completeq(struct ahc_softc *ahc)
         }
 }
 
-/*
- * Must be called with our lock held.
- */
-static __inline void
-ahc_schedule_runq(struct ahc_softc *ahc)
-{
-        tasklet_schedule(&ahc->platform_data->runq_tasklet);
-}
-
 static __inline struct ahc_linux_device*
 ahc_linux_get_device(struct ahc_softc *ahc, u_int channel, u_int target,
                      u_int lun, int alloc)
@@ -569,45 +554,6 @@ ahc_linux_run_complete_queue(struct ahc_softc *ahc)
 }
 
 static __inline void
-ahc_linux_check_device_queue(struct ahc_softc *ahc,
-                             struct ahc_linux_device *dev)
-{
-        if ((dev->flags & AHC_DEV_FREEZE_TIL_EMPTY) != 0
-         && dev->active == 0) {
-                dev->flags &= ~AHC_DEV_FREEZE_TIL_EMPTY;
-                dev->qfrozen--;
-        }
-
-        if (TAILQ_FIRST(&dev->busyq) == NULL
-         || dev->openings == 0 || dev->qfrozen != 0)
-                return;
-
-        ahc_linux_run_device_queue(ahc, dev);
-}
-
-static __inline struct ahc_linux_device *
-ahc_linux_next_device_to_run(struct ahc_softc *ahc)
-{
-        
-        if ((ahc->flags & AHC_RESOURCE_SHORTAGE) != 0
-            || (ahc->platform_data->qfrozen != 0))
-                return (NULL);
-        return (TAILQ_FIRST(&ahc->platform_data->device_runq));
-}
-
-static __inline void
-ahc_linux_run_device_queues(struct ahc_softc *ahc)
-{
-        struct ahc_linux_device *dev;
-
-        while ((dev = ahc_linux_next_device_to_run(ahc)) != NULL) {
-                TAILQ_REMOVE(&ahc->platform_data->device_runq, dev, links);
-                dev->flags &= ~AHC_DEV_ON_RUN_LIST;
-                ahc_linux_check_device_queue(ahc, dev);
-        }
-}
-
-static __inline void
 ahc_linux_unmap_scb(struct ahc_softc *ahc, struct scb *scb)
 {
         Scsi_Cmnd *cmd;
@@ -871,7 +817,6 @@ ahc_linux_queue(Scsi_Cmnd * cmd, void (*scsi_done) (Scsi_Cmnd *))
 {
         struct   ahc_softc *ahc;
         struct   ahc_linux_device *dev;
-        u_long   flags;
 
         ahc = *(struct ahc_softc **)cmd->device->host->hostdata;
 
@@ -880,42 +825,22 @@ ahc_linux_queue(Scsi_Cmnd * cmd, void (*scsi_done) (Scsi_Cmnd *))
          */
         cmd->scsi_done = scsi_done;
 
-        ahc_midlayer_entrypoint_lock(ahc, &flags);
-
         /*
          * Close the race of a command that was in the process of
          * being queued to us just as our simq was frozen.  Let
          * DV commands through so long as we are only frozen to
          * perform DV.
          */
-        if (ahc->platform_data->qfrozen != 0) {
+        if (ahc->platform_data->qfrozen != 0)
+                return SCSI_MLQUEUE_HOST_BUSY;
 
-                ahc_cmd_set_transaction_status(cmd, CAM_REQUEUE_REQ);
-                ahc_linux_queue_cmd_complete(ahc, cmd);
-                ahc_schedule_completeq(ahc);
-                ahc_midlayer_entrypoint_unlock(ahc, &flags);
-                return (0);
-        }
         dev = ahc_linux_get_device(ahc, cmd->device->channel, cmd->device->id,
                                    cmd->device->lun, /*alloc*/TRUE);
-        if (dev == NULL) {
-                ahc_cmd_set_transaction_status(cmd, CAM_RESRC_UNAVAIL);
-                ahc_linux_queue_cmd_complete(ahc, cmd);
-                ahc_schedule_completeq(ahc);
-                ahc_midlayer_entrypoint_unlock(ahc, &flags);
-                printf("%s: aic7xxx_linux_queue - Unable to allocate device!\n",
-                       ahc_name(ahc));
-                return (0);
-        }
+        BUG_ON(dev == NULL);
+
         cmd->result = CAM_REQ_INPROG << 16;
-        TAILQ_INSERT_TAIL(&dev->busyq, (struct ahc_cmd *)cmd, acmd_links.tqe);
-        if ((dev->flags & AHC_DEV_ON_RUN_LIST) == 0) {
-                TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq, dev, links);
-                dev->flags |= AHC_DEV_ON_RUN_LIST;
-                ahc_linux_run_device_queues(ahc);
-        }
-        ahc_midlayer_entrypoint_unlock(ahc, &flags);
-        return (0);
+
+        return ahc_linux_run_command(ahc, dev, cmd);
 }
 
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
@@ -987,8 +912,7 @@ ahc_linux_slave_destroy(Scsi_Device *device)
         if (dev != NULL
          && (dev->flags & AHC_DEV_SLAVE_CONFIGURED) != 0) {
                 dev->flags |= AHC_DEV_UNCONFIGURED;
-                if (TAILQ_EMPTY(&dev->busyq)
-                 && dev->active == 0
+                if (dev->active == 0
                  && (dev->flags & AHC_DEV_TIMER_ACTIVE) == 0)
                         ahc_linux_free_device(ahc, dev);
         }
@@ -1206,33 +1130,6 @@ Scsi_Host_Template aic7xxx_driver_template = {
 
 /**************************** Tasklet Handler *********************************/
 
-/*
- * In 2.4.X and above, this routine is called from a tasklet,
- * so we must re-acquire our lock prior to executing this code.
- * In all prior kernels, ahc_schedule_runq() calls this routine
- * directly and ahc_schedule_runq() is called with our lock held.
- */
-static void
-ahc_runq_tasklet(unsigned long data)
-{
-        struct ahc_softc* ahc;
-        struct ahc_linux_device *dev;
-        u_long flags;
-
-        ahc = (struct ahc_softc *)data;
-        ahc_lock(ahc, &flags);
-        while ((dev = ahc_linux_next_device_to_run(ahc)) != NULL) {
-        
-                TAILQ_REMOVE(&ahc->platform_data->device_runq, dev, links);
-                dev->flags &= ~AHC_DEV_ON_RUN_LIST;
-                ahc_linux_check_device_queue(ahc, dev);
-                /* Yeild to our interrupt handler */
-                ahc_unlock(ahc, &flags);
-                ahc_lock(ahc, &flags);
-        }
-        ahc_unlock(ahc, &flags);
-}
-
 /******************************** Macros **************************************/
 #define BUILD_SCSIID(ahc, cmd)                                              \
         ((((cmd)->device->id << TID_SHIFT) & TID)                           \
@@ -1728,8 +1625,6 @@ ahc_platform_alloc(struct ahc_softc *ahc, void *platform_arg)
         ahc->platform_data->completeq_timer.function =
             (ahc_linux_callback_t *)ahc_linux_thread_run_complete_queue;
         init_MUTEX_LOCKED(&ahc->platform_data->eh_sem);
-        tasklet_init(&ahc->platform_data->runq_tasklet, ahc_runq_tasklet,
-                     (unsigned long)ahc);
         ahc->seltime = (aic7xxx_seltime & 0x3) << 4;
         ahc->seltime_b = (aic7xxx_seltime & 0x3) << 4;
         if (aic7xxx_pci_parity == 0)
@@ -1747,7 +1642,6 @@ ahc_platform_free(struct ahc_softc *ahc)
 
         if (ahc->platform_data != NULL) {
                 del_timer_sync(&ahc->platform_data->completeq_timer);
-                tasklet_kill(&ahc->platform_data->runq_tasklet);
                 if (ahc->platform_data->host != NULL) {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
                         scsi_remove_host(ahc->platform_data->host);
@@ -1906,71 +1800,7 @@ int
 ahc_platform_abort_scbs(struct ahc_softc *ahc, int target, char channel,
                         int lun, u_int tag, role_t role, uint32_t status)
 {
-        int chan;
-        int maxchan;
-        int targ;
-        int maxtarg;
-        int clun;
-        int maxlun;
-        int count;
-
-        if (tag != SCB_LIST_NULL)
-                return (0);
-
-        chan = 0;
-        if (channel != ALL_CHANNELS) {
-                chan = channel - 'A';
-                maxchan = chan + 1;
-        } else {
-                maxchan = (ahc->features & AHC_TWIN) ? 2 : 1;
-        }
-        targ = 0;
-        if (target != CAM_TARGET_WILDCARD) {
-                targ = target;
-                maxtarg = targ + 1;
-        } else {
-                maxtarg = (ahc->features & AHC_WIDE) ? 16 : 8;
-        }
-        clun = 0;
-        if (lun != CAM_LUN_WILDCARD) {
-                clun = lun;
-                maxlun = clun + 1;
-        } else {
-                maxlun = AHC_NUM_LUNS;
-        }
-
-        count = 0;
-        for (; chan < maxchan; chan++) {
-
-                for (; targ < maxtarg; targ++) {
-
-                        for (; clun < maxlun; clun++) {
-                                struct ahc_linux_device *dev;
-                                struct ahc_busyq *busyq;
-                                struct ahc_cmd *acmd;
-
-                                dev = ahc_linux_get_device(ahc, chan,
-                                                           targ, clun,
-                                                           /*alloc*/FALSE);
-                                if (dev == NULL)
-                                        continue;
-
-                                busyq = &dev->busyq;
-                                while ((acmd = TAILQ_FIRST(busyq)) != NULL) {
-                                        Scsi_Cmnd *cmd;
-
-                                        cmd = &acmd_scsi_cmd(acmd);
-                                        TAILQ_REMOVE(busyq, acmd,
-                                                     acmd_links.tqe);
-                                        count++;
-                                        cmd->result = status << 16;
-                                        ahc_linux_queue_cmd_complete(ahc, cmd);
-                                }
-                        }
-                }
-        }
-
-        return (count);
+        return 0;
 }
 
 static void
@@ -2045,213 +1875,203 @@ ahc_linux_device_queue_depth(struct ahc_softc *ahc,
         }
 }
 
-static void
-ahc_linux_run_device_queue(struct ahc_softc *ahc, struct ahc_linux_device *dev)
+static int
+ahc_linux_run_command(struct ahc_softc *ahc, struct ahc_linux_device *dev,
+                      struct scsi_cmnd *cmd)
 {
-        struct   ahc_cmd *acmd;
-        struct   scsi_cmnd *cmd;
         struct   scb *scb;
         struct   hardware_scb *hscb;
         struct   ahc_initiator_tinfo *tinfo;
         struct   ahc_tmode_tstate *tstate;
         uint16_t mask;
+        struct scb_tailq *untagged_q = NULL;
 
-        if ((dev->flags & AHC_DEV_ON_RUN_LIST) != 0)
-                panic("running device on run list");
+        /*
+         * Schedule us to run later.  The only reason we are not
+         * running is because the whole controller Q is frozen.
+         */
+        if (ahc->platform_data->qfrozen != 0)
+                return SCSI_MLQUEUE_HOST_BUSY;
 
-        while ((acmd = TAILQ_FIRST(&dev->busyq)) != NULL
-            && dev->openings > 0 && dev->qfrozen == 0) {
+        /*
+         * We only allow one untagged transaction
+         * per target in the initiator role unless
+         * we are storing a full busy target *lun*
+         * table in SCB space.
+         */
+        if (!blk_rq_tagged(cmd->request)
+            && (ahc->features & AHC_SCB_BTT) == 0) {
+                int target_offset;
 
-                /*
-                 * Schedule us to run later.  The only reason we are not
-                 * running is because the whole controller Q is frozen.
-                 */
-                if (ahc->platform_data->qfrozen != 0) {
-                        TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq,
-                                          dev, links);
-                        dev->flags |= AHC_DEV_ON_RUN_LIST;
-                        return;
-                }
-                /*
-                 * Get an scb to use.
-                 */
-                if ((scb = ahc_get_scb(ahc)) == NULL) {
-                        TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq,
-                                         dev, links);
-                        dev->flags |= AHC_DEV_ON_RUN_LIST;
+                target_offset = cmd->device->id + cmd->device->channel * 8;
+                untagged_q = &(ahc->untagged_queues[target_offset]);
+                if (!TAILQ_EMPTY(untagged_q))
+                        /* if we're already executing an untagged command
+                         * we're busy to another */
+                        return SCSI_MLQUEUE_DEVICE_BUSY;
+        }
+
+        /*
+         * Get an scb to use.
+         */
+        if ((scb = ahc_get_scb(ahc)) == NULL) {
                         ahc->flags |= AHC_RESOURCE_SHORTAGE;
-                        return;
-                }
-                TAILQ_REMOVE(&dev->busyq, acmd, acmd_links.tqe);
-                cmd = &acmd_scsi_cmd(acmd);
-                scb->io_ctx = cmd;
-                scb->platform_data->dev = dev;
-                hscb = scb->hscb;
-                cmd->host_scribble = (char *)scb;
+                        return SCSI_MLQUEUE_HOST_BUSY;
+        }
 
-                /*
-                 * Fill out basics of the HSCB.
-                 */
-                hscb->control = 0;
-                hscb->scsiid = BUILD_SCSIID(ahc, cmd);
-                hscb->lun = cmd->device->lun;
-                mask = SCB_GET_TARGET_MASK(ahc, scb);
-                tinfo = ahc_fetch_transinfo(ahc, SCB_GET_CHANNEL(ahc, scb),
-                                            SCB_GET_OUR_ID(scb),
-                                            SCB_GET_TARGET(ahc, scb), &tstate);
-                hscb->scsirate = tinfo->scsirate;
-                hscb->scsioffset = tinfo->curr.offset;
-                if ((tstate->ultraenb & mask) != 0)
-                        hscb->control |= ULTRAENB;
-
-                if ((ahc->user_discenable & mask) != 0)
-                        hscb->control |= DISCENB;
-
-                if ((tstate->auto_negotiate & mask) != 0) {
-                        scb->flags |= SCB_AUTO_NEGOTIATE;
-                        scb->hscb->control |= MK_MESSAGE;
-                }
+        scb->io_ctx = cmd;
+        scb->platform_data->dev = dev;
+        hscb = scb->hscb;
+        cmd->host_scribble = (char *)scb;
 
-                if ((dev->flags & (AHC_DEV_Q_TAGGED|AHC_DEV_Q_BASIC)) != 0) {
+        /*
+         * Fill out basics of the HSCB.
+         */
+        hscb->control = 0;
+        hscb->scsiid = BUILD_SCSIID(ahc, cmd);
+        hscb->lun = cmd->device->lun;
+        mask = SCB_GET_TARGET_MASK(ahc, scb);
+        tinfo = ahc_fetch_transinfo(ahc, SCB_GET_CHANNEL(ahc, scb),
+                                    SCB_GET_OUR_ID(scb),
+                                    SCB_GET_TARGET(ahc, scb), &tstate);
+        hscb->scsirate = tinfo->scsirate;
+        hscb->scsioffset = tinfo->curr.offset;
+        if ((tstate->ultraenb & mask) != 0)
+                hscb->control |= ULTRAENB;
+        
+        if ((ahc->user_discenable & mask) != 0)
+                hscb->control |= DISCENB;
+        
+        if ((tstate->auto_negotiate & mask) != 0) {
+                scb->flags |= SCB_AUTO_NEGOTIATE;
+                scb->hscb->control |= MK_MESSAGE;
+        }
+
+        if ((dev->flags & (AHC_DEV_Q_TAGGED|AHC_DEV_Q_BASIC)) != 0) {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,5,0)
-                        int     msg_bytes;
-                        uint8_t tag_msgs[2];
-
-                        msg_bytes = scsi_populate_tag_msg(cmd, tag_msgs);
-                        if (msg_bytes && tag_msgs[0] != MSG_SIMPLE_TASK) {
-                                hscb->control |= tag_msgs[0];
-                                if (tag_msgs[0] == MSG_ORDERED_TASK)
-                                        dev->commands_since_idle_or_otag = 0;
-                        } else
-#endif
-                        if (dev->commands_since_idle_or_otag == AHC_OTAG_THRESH
-                         && (dev->flags & AHC_DEV_Q_TAGGED) != 0) {
-                                hscb->control |= MSG_ORDERED_TASK;
+                int     msg_bytes;
+                uint8_t tag_msgs[2];
+                
+                msg_bytes = scsi_populate_tag_msg(cmd, tag_msgs);
+                if (msg_bytes && tag_msgs[0] != MSG_SIMPLE_TASK) {
+                        hscb->control |= tag_msgs[0];
+                        if (tag_msgs[0] == MSG_ORDERED_TASK)
                                 dev->commands_since_idle_or_otag = 0;
-                        } else {
-                                hscb->control |= MSG_SIMPLE_TASK;
-                        }
-                }
-
-                hscb->cdb_len = cmd->cmd_len;
-                if (hscb->cdb_len <= 12) {
-                        memcpy(hscb->shared_data.cdb, cmd->cmnd, hscb->cdb_len);
+                } else
+#endif
+                if (dev->commands_since_idle_or_otag == AHC_OTAG_THRESH
+                    && (dev->flags & AHC_DEV_Q_TAGGED) != 0) {
+                        hscb->control |= MSG_ORDERED_TASK;
+                        dev->commands_since_idle_or_otag = 0;
                 } else {
-                        memcpy(hscb->cdb32, cmd->cmnd, hscb->cdb_len);
-                        scb->flags |= SCB_CDB32_PTR;
+                        hscb->control |= MSG_SIMPLE_TASK;
                 }
+        }
 
-                scb->platform_data->xfer_len = 0;
-                ahc_set_residual(scb, 0);
-                ahc_set_sense_residual(scb, 0);
-                scb->sg_count = 0;
-                if (cmd->use_sg != 0) {
-                        struct  ahc_dma_seg *sg;
-                        struct  scatterlist *cur_seg;
-                        struct  scatterlist *end_seg;
-                        int     nseg;
-
-                        cur_seg = (struct scatterlist *)cmd->request_buffer;
-                        nseg = pci_map_sg(ahc->dev_softc, cur_seg, cmd->use_sg,
-                            cmd->sc_data_direction);
-                        end_seg = cur_seg + nseg;
-                        /* Copy the segments into the SG list. */
-                        sg = scb->sg_list;
-                        /*
-                         * The sg_count may be larger than nseg if
-                         * a transfer crosses a 32bit page.
-                         */ 
-                        while (cur_seg < end_seg) {
-                                dma_addr_t addr;
-                                bus_size_t len;
-                                int consumed;
-
-                                addr = sg_dma_address(cur_seg);
-                                len = sg_dma_len(cur_seg);
-                                consumed = ahc_linux_map_seg(ahc, scb,
-                                                             sg, addr, len);
-                                sg += consumed;
-                                scb->sg_count += consumed;
-                                cur_seg++;
-                        }
-                        sg--;
-                        sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);
-
-                        /*
-                         * Reset the sg list pointer.
-                         */
-                        scb->hscb->sgptr =
-                            ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);
+        hscb->cdb_len = cmd->cmd_len;
+        if (hscb->cdb_len <= 12) {
+                memcpy(hscb->shared_data.cdb, cmd->cmnd, hscb->cdb_len);
+        } else {
+                memcpy(hscb->cdb32, cmd->cmnd, hscb->cdb_len);
+                scb->flags |= SCB_CDB32_PTR;
+        }
 
-                        /*
-                         * Copy the first SG into the "current"
-                         * data pointer area.
-                         */
-                        scb->hscb->dataptr = scb->sg_list->addr;
-                        scb->hscb->datacnt = scb->sg_list->len;
-                } else if (cmd->request_bufflen != 0) {
-                        struct   ahc_dma_seg *sg;
+        scb->platform_data->xfer_len = 0;
+        ahc_set_residual(scb, 0);
+        ahc_set_sense_residual(scb, 0);
+        scb->sg_count = 0;
+        if (cmd->use_sg != 0) {
+                struct  ahc_dma_seg *sg;
+                struct  scatterlist *cur_seg;
+                struct  scatterlist *end_seg;
+                int     nseg;
+
+                cur_seg = (struct scatterlist *)cmd->request_buffer;
+                nseg = pci_map_sg(ahc->dev_softc, cur_seg, cmd->use_sg,
+                                  cmd->sc_data_direction);
+                end_seg = cur_seg + nseg;
+                /* Copy the segments into the SG list. */
+                sg = scb->sg_list;
+                /*
+                 * The sg_count may be larger than nseg if
+                 * a transfer crosses a 32bit page.
+                 */ 
+                while (cur_seg < end_seg) {
                         dma_addr_t addr;
-
-                        sg = scb->sg_list;
-                        addr = pci_map_single(ahc->dev_softc,
-                               cmd->request_buffer,
-                               cmd->request_bufflen,
-                               cmd->sc_data_direction);
-                        scb->platform_data->buf_busaddr = addr;
-                        scb->sg_count = ahc_linux_map_seg(ahc, scb,
-                                                          sg, addr,
-                                                          cmd->request_bufflen);
-                        sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);
-
-                        /*
-                         * Reset the sg list pointer.
-                         */
-                        scb->hscb->sgptr =
-                            ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);
-
-                        /*
-                         * Copy the first SG into the "current"
-                         * data pointer area.
-                         */
-                        scb->hscb->dataptr = sg->addr;
-                        scb->hscb->datacnt = sg->len;
-                } else {
-                        scb->hscb->sgptr = ahc_htole32(SG_LIST_NULL);
-                        scb->hscb->dataptr = 0;
-                        scb->hscb->datacnt = 0;
-                        scb->sg_count = 0;
+                        bus_size_t len;
+                        int consumed;
+
+                        addr = sg_dma_address(cur_seg);
+                        len = sg_dma_len(cur_seg);
+                        consumed = ahc_linux_map_seg(ahc, scb,
+                                                     sg, addr, len);
+                        sg += consumed;
+                        scb->sg_count += consumed;
+                        cur_seg++;
                 }
+                sg--;
+                sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);
 
-                ahc_sync_sglist(ahc, scb, BUS_DMASYNC_PREWRITE);
-                LIST_INSERT_HEAD(&ahc->pending_scbs, scb, pending_links);
-                dev->openings--;
-                dev->active++;
-                dev->commands_issued++;
-                if ((dev->flags & AHC_DEV_PERIODIC_OTAG) != 0)
-                        dev->commands_since_idle_or_otag++;
+                /*
+                 * Reset the sg list pointer.
+                 */
+                scb->hscb->sgptr =
+                        ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);
+                
+                /*
+                 * Copy the first SG into the "current"
+                 * data pointer area.
+                 */
+                scb->hscb->dataptr = scb->sg_list->addr;
+                scb->hscb->datacnt = scb->sg_list->len;
+        } else if (cmd->request_bufflen != 0) {
+                struct   ahc_dma_seg *sg;
+                dma_addr_t addr;
+
+                sg = scb->sg_list;
+                addr = pci_map_single(ahc->dev_softc,
+                                      cmd->request_buffer,
+                                      cmd->request_bufflen,
+                                      cmd->sc_data_direction);
+                scb->platform_data->buf_busaddr = addr;
+                scb->sg_count = ahc_linux_map_seg(ahc, scb,
+                                                  sg, addr,
+                                                  cmd->request_bufflen);
+                sg->len |= ahc_htole32(AHC_DMA_LAST_SEG);
 
                 /*
-                 * We only allow one untagged transaction
-                 * per target in the initiator role unless
-                 * we are storing a full busy target *lun*
-                 * table in SCB space.
+                 * Reset the sg list pointer.
                  */
-                if ((scb->hscb->control & (TARGET_SCB|TAG_ENB)) == 0
-                 && (ahc->features & AHC_SCB_BTT) == 0) {
-                        struct scb_tailq *untagged_q;
-                        int target_offset;
-
-                        target_offset = SCB_GET_TARGET_OFFSET(ahc, scb);
-                        untagged_q = &(ahc->untagged_queues[target_offset]);
-                        TAILQ_INSERT_TAIL(untagged_q, scb, links.tqe);
-                        scb->flags |= SCB_UNTAGGEDQ;
-                        if (TAILQ_FIRST(untagged_q) != scb)
-                                continue;
-                }
-                scb->flags |= SCB_ACTIVE;
-                ahc_queue_scb(ahc, scb);
+                scb->hscb->sgptr =
+                        ahc_htole32(scb->sg_list_phys | SG_FULL_RESID);
+
+                /*
+                 * Copy the first SG into the "current"
+                 * data pointer area.
+                 */
+                scb->hscb->dataptr = sg->addr;
+                scb->hscb->datacnt = sg->len;
+        } else {
+                scb->hscb->sgptr = ahc_htole32(SG_LIST_NULL);
+                scb->hscb->dataptr = 0;
+                scb->hscb->datacnt = 0;
+                scb->sg_count = 0;
+        }
+
+        LIST_INSERT_HEAD(&ahc->pending_scbs, scb, pending_links);
+        dev->openings--;
+        dev->active++;
+        dev->commands_issued++;
+        if ((dev->flags & AHC_DEV_PERIODIC_OTAG) != 0)
+                dev->commands_since_idle_or_otag++;
+        
+        scb->flags |= SCB_ACTIVE;
+        if (untagged_q) {
+                TAILQ_INSERT_TAIL(untagged_q, scb, links.tqe);
+                scb->flags |= SCB_UNTAGGEDQ;
         }
+        ahc_queue_scb(ahc, scb);
+        return 0;
 }
 
 /*
@@ -2267,8 +2087,6 @@ ahc_linux_isr(int irq, void *dev_id, struct pt_regs * regs)
         ahc = (struct ahc_softc *) dev_id;
         ahc_lock(ahc, &flags); 
         ours = ahc_intr(ahc);
-        if (ahc_linux_next_device_to_run(ahc) != NULL)
-                ahc_schedule_runq(ahc);
         ahc_linux_run_complete_queue(ahc);
         ahc_unlock(ahc, &flags);
         return IRQ_RETVAL(ours);
@@ -2349,7 +2167,6 @@ ahc_linux_alloc_device(struct ahc_softc *ahc,
                 return (NULL);
         memset(dev, 0, sizeof(*dev));
         init_timer(&dev->timer);
-        TAILQ_INIT(&dev->busyq);
         dev->flags = AHC_DEV_UNCONFIGURED;
         dev->lun = lun;
         dev->target = targ;
@@ -2515,7 +2332,7 @@ ahc_done(struct ahc_softc *ahc, struct scb *scb)
                 target_offset = SCB_GET_TARGET_OFFSET(ahc, scb);
                 untagged_q = &(ahc->untagged_queues[target_offset]);
                 TAILQ_REMOVE(untagged_q, scb, links.tqe);
-                ahc_run_untagged_queue(ahc, untagged_q);
+                BUG_ON(!TAILQ_EMPTY(untagged_q));
         }
 
         if ((scb->flags & SCB_ACTIVE) == 0) {
@@ -2606,12 +2423,11 @@ ahc_done(struct ahc_softc *ahc, struct scb *scb)
         if (dev->active == 0)
                 dev->commands_since_idle_or_otag = 0;
 
-        if (TAILQ_EMPTY(&dev->busyq)) {
-                if ((dev->flags & AHC_DEV_UNCONFIGURED) != 0
-                 && dev->active == 0
-                 && (dev->flags & AHC_DEV_TIMER_ACTIVE) == 0)
-                        ahc_linux_free_device(ahc, dev);
-        } else if ((dev->flags & AHC_DEV_ON_RUN_LIST) == 0) {
+        if ((dev->flags & AHC_DEV_UNCONFIGURED) != 0
+            && dev->active == 0
+            && (dev->flags & AHC_DEV_TIMER_ACTIVE) == 0)
+                ahc_linux_free_device(ahc, dev);
+        else if ((dev->flags & AHC_DEV_ON_RUN_LIST) == 0) {
                 TAILQ_INSERT_TAIL(&ahc->platform_data->device_runq, dev, links);
                 dev->flags |= AHC_DEV_ON_RUN_LIST;
         }
@@ -2940,7 +2756,6 @@ ahc_linux_release_simq(u_long arg)
                 ahc->platform_data->qfrozen--;
         if (ahc->platform_data->qfrozen == 0)
                 unblock_reqs = 1;
-        ahc_schedule_runq(ahc);
         ahc_unlock(ahc, &s);
         /*
          * There is still a race here.  The mid-layer
@@ -2965,11 +2780,7 @@ ahc_linux_dev_timed_unfreeze(u_long arg)
         dev->flags &= ~AHC_DEV_TIMER_ACTIVE;
         if (dev->qfrozen > 0)
                 dev->qfrozen--;
-        if (dev->qfrozen == 0
-         && (dev->flags & AHC_DEV_ON_RUN_LIST) == 0)
-                ahc_linux_run_device_queue(ahc, dev);
-        if (TAILQ_EMPTY(&dev->busyq)
-         && dev->active == 0)
+        if (dev->active == 0)
                 __ahc_linux_free_device(ahc, dev);
         ahc_unlock(ahc, &s);
 }
@@ -2978,8 +2789,6 @@ static int
 ahc_linux_queue_recovery_cmd(Scsi_Cmnd *cmd, scb_flag flag)
 {
         struct ahc_softc *ahc;
-        struct ahc_cmd *acmd;
-        struct ahc_cmd *list_acmd;
         struct ahc_linux_device *dev;
         struct scb *pending_scb;
         u_long s;
@@ -2998,7 +2807,6 @@ ahc_linux_queue_recovery_cmd(Scsi_Cmnd *cmd, scb_flag flag)
         paused = FALSE;
         wait = FALSE;
         ahc = *(struct ahc_softc **)cmd->device->host->hostdata;
-        acmd = (struct ahc_cmd *)cmd;
 
         printf("%s:%d:%d:%d: Attempting to queue a%s message\n",
                ahc_name(ahc), cmd->device->channel,
@@ -3048,24 +2856,6 @@ ahc_linux_queue_recovery_cmd(Scsi_Cmnd *cmd, scb_flag flag)
                 goto no_cmd;
         }
 
-        TAILQ_FOREACH(list_acmd, &dev->busyq, acmd_links.tqe) {
-                if (list_acmd == acmd)
-                        break;
-        }
-
-        if (list_acmd != NULL) {
-                printf("%s:%d:%d:%d: Command found on device queue\n",
-                       ahc_name(ahc), cmd->device->channel, cmd->device->id,
-                       cmd->device->lun);
-                if (flag == SCB_ABORT) {
-                        TAILQ_REMOVE(&dev->busyq, list_acmd, acmd_links.tqe);
-                        cmd->result = DID_ABORT << 16;
-                        ahc_linux_queue_cmd_complete(ahc, cmd);
-                        retval = SUCCESS;
-                        goto done;
-                }
-        }
-
         if ((dev->flags & (AHC_DEV_Q_BASIC|AHC_DEV_Q_TAGGED)) == 0
          && ahc_search_untagged_queues(ahc, cmd, cmd->device->id,
                                        cmd->device->channel + 'A',
@@ -3299,7 +3089,6 @@ done:
                 }
                 spin_lock_irq(&ahc->platform_data->spin_lock);
         }
-        ahc_schedule_runq(ahc);
         ahc_linux_run_complete_queue(ahc);
         ahc_midlayer_entrypoint_unlock(ahc, &s);
         return (retval);
@@ -3308,40 +3097,6 @@ done:
 void
 ahc_platform_dump_card_state(struct ahc_softc *ahc)
 {
-        struct ahc_linux_device *dev;
-        int channel;
-        int maxchannel;
-        int target;
-        int maxtarget;
-        int lun;
-        int i;
-
-        maxchannel = (ahc->features & AHC_TWIN) ? 1 : 0;
-        maxtarget = (ahc->features & AHC_WIDE) ? 15 : 7;
-        for (channel = 0; channel <= maxchannel; channel++) {
-
-                for (target = 0; target <=maxtarget; target++) {
-
-                        for (lun = 0; lun < AHC_NUM_LUNS; lun++) {
-                                struct ahc_cmd *acmd;
-
-                                dev = ahc_linux_get_device(ahc, channel, target,
-                                                           lun, /*alloc*/FALSE);
-                                if (dev == NULL)
-                                        continue;
-
-                                printf("DevQ(%d:%d:%d): ",
-                                       channel, target, lun);
-                                i = 0;
-                                TAILQ_FOREACH(acmd, &dev->busyq,
-                                              acmd_links.tqe) {
-                                        if (i++ > AHC_SCB_MAX)
-                                                break;
-                                }
-                                printf("%d waiting\n", i);
-                        }
-                }
-        }
 }
 
 static void ahc_linux_exit(void);
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.h b/drivers/scsi/aic7xxx/aic7xxx_osm.h
index ed9027bd8a40..956097035219 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.h
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.h
@@ -66,11 +66,11 @@
 #include <linux/pci.h>
 #include <linux/smp_lock.h>
 #include <linux/version.h>
+#include <linux/interrupt.h>
 #include <linux/module.h>
 #include <asm/byteorder.h>
 #include <asm/io.h>
 
-#include <linux/interrupt.h> /* For tasklet support. */
 #include <linux/config.h>
 #include <linux/slab.h>
 
@@ -341,7 +341,6 @@ typedef enum {
 struct ahc_linux_target;
 struct ahc_linux_device {
         TAILQ_ENTRY(ahc_linux_device) links;
-        struct          ahc_busyq busyq;
 
         /*
          * The number of transactions currently
@@ -488,7 +487,6 @@ struct ahc_platform_data {
         struct ahc_completeq     completeq;
 
         spinlock_t               spin_lock;
-        struct tasklet_struct    runq_tasklet;
         u_int                    qfrozen;
         pid_t                    dv_pid;
         struct timer_list        completeq_timer;