2 files changed, 34 insertions, 102 deletions

diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index d402aff5f314..47c29a98c922 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -28,7 +28,6 @@
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_host.h>
 #include <scsi/scsi_tgt.h>
-#include <../drivers/md/dm-bio-list.h>
 
 #include "scsi_tgt_priv.h"
 
@@ -42,9 +41,8 @@ static struct kmem_cache *scsi_tgt_cmd_cache;
 struct scsi_tgt_cmd {
         /* TODO replace work with James b's code */
         struct work_struct work;
-        /* TODO replace the lists with a large bio */
-        struct bio_list xfer_done_list;
-        struct bio_list xfer_list;
+        /* TODO fix limits of some drivers */
+        struct bio *bio;
 
         struct list_head hash_list;
         struct request *rq;
@@ -93,7 +91,12 @@ struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *shost,
         if (!tcmd)
                 goto put_dev;
 
-        rq = blk_get_request(shost->uspace_req_q, write, gfp_mask);
+        /*
+         * The blk helpers are used to the READ/WRITE requests
+         * transfering data from a initiator point of view. Since
+         * we are in target mode we want the opposite.
+         */
+        rq = blk_get_request(shost->uspace_req_q, !write, gfp_mask);
         if (!rq)
                 goto free_tcmd;
 
@@ -111,8 +114,6 @@ struct scsi_cmnd *scsi_host_get_command(struct Scsi_Host *shost,
         rq->cmd_flags |= REQ_TYPE_BLOCK_PC;
         rq->end_io_data = tcmd;
 
-        bio_list_init(&tcmd->xfer_list);
-        bio_list_init(&tcmd->xfer_done_list);
         tcmd->rq = rq;
 
         return cmd;
@@ -157,22 +158,6 @@ void scsi_host_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
 }
 EXPORT_SYMBOL_GPL(scsi_host_put_command);
 
-static void scsi_unmap_user_pages(struct scsi_tgt_cmd *tcmd)
-{
-        struct bio *bio;
-
-        /* must call bio_endio in case bio was bounced */
-        while ((bio = bio_list_pop(&tcmd->xfer_done_list))) {
-                bio_endio(bio, bio->bi_size, 0);
-                bio_unmap_user(bio);
-        }
-
-        while ((bio = bio_list_pop(&tcmd->xfer_list))) {
-                bio_endio(bio, bio->bi_size, 0);
-                bio_unmap_user(bio);
-        }
-}
-
 static void cmd_hashlist_del(struct scsi_cmnd *cmd)
 {
         struct request_queue *q = cmd->request->q;
@@ -185,6 +170,11 @@ static void cmd_hashlist_del(struct scsi_cmnd *cmd)
         spin_unlock_irqrestore(&qdata->cmd_hash_lock, flags);
 }
 
+static void scsi_unmap_user_pages(struct scsi_tgt_cmd *tcmd)
+{
+        blk_rq_unmap_user(tcmd->bio);
+}
+
 static void scsi_tgt_cmd_destroy(struct work_struct *work)
 {
         struct scsi_tgt_cmd *tcmd =
@@ -193,16 +183,6 @@ static void scsi_tgt_cmd_destroy(struct work_struct *work)
 
         dprintk("cmd %p %d %lu\n", cmd, cmd->sc_data_direction,
                 rq_data_dir(cmd->request));
-        /*
-         * We fix rq->cmd_flags here since when we told bio_map_user
-         * to write vm for WRITE commands, blk_rq_bio_prep set
-         * rq_data_dir the flags to READ.
-         */
-        if (cmd->sc_data_direction == DMA_TO_DEVICE)
-                cmd->request->cmd_flags |= REQ_RW;
-        else
-                cmd->request->cmd_flags &= ~REQ_RW;
-
         scsi_unmap_user_pages(tcmd);
         scsi_host_put_command(scsi_tgt_cmd_to_host(cmd), cmd);
 }
@@ -215,6 +195,7 @@ static void init_scsi_tgt_cmd(struct request *rq, struct scsi_tgt_cmd *tcmd,
         struct list_head *head;
 
         tcmd->tag = tag;
+        tcmd->bio = NULL;
         INIT_WORK(&tcmd->work, scsi_tgt_cmd_destroy);
         spin_lock_irqsave(&qdata->cmd_hash_lock, flags);
         head = &qdata->cmd_hash[cmd_hashfn(tag)];
@@ -419,52 +400,33 @@ static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
         struct request *rq = cmd->request;
         void *uaddr = tcmd->buffer;
         unsigned int len = tcmd->bufflen;
-        struct bio *bio;
         int err;
 
-        while (len > 0) {
-                dprintk("%lx %u\n", (unsigned long) uaddr, len);
-                bio = bio_map_user(q, NULL, (unsigned long) uaddr, len, rw);
-                if (IS_ERR(bio)) {
-                        err = PTR_ERR(bio);
-                        dprintk("fail to map %lx %u %d %x\n",
-                                (unsigned long) uaddr, len, err, cmd->cmnd[0]);
-                        goto unmap_bios;
-                }
-
-                uaddr += bio->bi_size;
-                len -= bio->bi_size;
-
+        dprintk("%lx %u\n", (unsigned long) uaddr, len);
+        err = blk_rq_map_user(q, rq, uaddr, len);
+        if (err) {
                 /*
-                 * The first bio is added and merged. We could probably
-                 * try to add others using scsi_merge_bio() but for now
-                 * we keep it simple. The first bio should be pretty large
-                 * (either hitting the 1 MB bio pages limit or a queue limit)
-                 * already but for really large IO we may want to try and
-                 * merge these.
+                 * TODO: need to fixup sg_tablesize, max_segment_size,
+                 * max_sectors, etc for modern HW and software drivers
+                 * where this value is bogus.
+                 *
+                 * TODO2: we can alloc a reserve buffer of max size
+                 * we can handle and do the slow copy path for really large
+                 * IO.
                  */
-                if (!rq->bio) {
-                        blk_rq_bio_prep(q, rq, bio);
-                        rq->data_len = bio->bi_size;
-                } else
-                        /* put list of bios to transfer in next go around */
-                        bio_list_add(&tcmd->xfer_list, bio);
+                eprintk("Could not handle request of size %u.\n", len);
+                return err;
         }
 
-        cmd->offset = 0;
+        tcmd->bio = rq->bio;
         err = scsi_tgt_init_cmd(cmd, GFP_KERNEL);
         if (err)
-                goto unmap_bios;
+                goto unmap_rq;
 
         return 0;
 
-unmap_bios:
-        if (rq->bio) {
-                bio_unmap_user(rq->bio);
-                while ((bio = bio_list_pop(&tcmd->xfer_list)))
-                        bio_unmap_user(bio);
-        }
-
+unmap_rq:
+        scsi_unmap_user_pages(tcmd);
         return err;
 }
 
@@ -473,12 +435,10 @@ static int scsi_tgt_transfer_data(struct scsi_cmnd *);
 static void scsi_tgt_data_transfer_done(struct scsi_cmnd *cmd)
 {
         struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
-        struct bio *bio;
         int err;
 
         /* should we free resources here on error ? */
         if (cmd->result) {
-send_uspace_err:
                 err = scsi_tgt_uspace_send_status(cmd, tcmd->tag);
                 if (err <= 0)
                         /* the tgt uspace eh will have to pick this up */
@@ -490,34 +450,8 @@ send_uspace_err:
                 cmd, cmd->request_bufflen, tcmd->bufflen);
 
         scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
-        bio_list_add(&tcmd->xfer_done_list, cmd->request->bio);
-
         tcmd->buffer += cmd->request_bufflen;
-        cmd->offset += cmd->request_bufflen;
-
-        if (!tcmd->xfer_list.head) {
-                scsi_tgt_transfer_response(cmd);
-                return;
-        }
-
-        dprintk("cmd2 %p request_bufflen %u bufflen %u\n",
-                cmd, cmd->request_bufflen, tcmd->bufflen);
-
-        bio = bio_list_pop(&tcmd->xfer_list);
-        BUG_ON(!bio);
-
-        blk_rq_bio_prep(cmd->request->q, cmd->request, bio);
-        cmd->request->data_len = bio->bi_size;
-        err = scsi_tgt_init_cmd(cmd, GFP_ATOMIC);
-        if (err) {
-                cmd->result = DID_ERROR << 16;
-                goto send_uspace_err;
-        }
-
-        if (scsi_tgt_transfer_data(cmd)) {
-                cmd->result = DID_NO_CONNECT << 16;
-                goto send_uspace_err;
-        }
+        scsi_tgt_transfer_response(cmd);
 }
 
 static int scsi_tgt_transfer_data(struct scsi_cmnd *cmd)
@@ -617,8 +551,9 @@ int scsi_tgt_kspace_exec(int host_no, u64 tag, int result, u32 len,
         }
         cmd = rq->special;
 
-        dprintk("cmd %p result %d len %d bufflen %u %lu %x\n", cmd,
-                result, len, cmd->request_bufflen, rq_data_dir(rq), cmd->cmnd[0]);
+        dprintk("cmd %p scb %x result %d len %d bufflen %u %lu %x\n",
+                cmd, cmd->cmnd[0], result, len, cmd->request_bufflen,
+                rq_data_dir(rq), cmd->cmnd[0]);
 
         if (result == TASK_ABORTED) {
                 scsi_tgt_abort_cmd(shost, cmd);
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index d6948d0e8cdb..a2e0c1032491 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -73,9 +73,6 @@ struct scsi_cmnd {
         unsigned short use_sg;  /* Number of pieces of scatter-gather */
         unsigned short sglist_len;      /* size of malloc'd scatter-gather list */
 
-        /* offset in cmd we are at (for multi-transfer tgt cmds) */
-        unsigned offset;
-
         unsigned underflow;     /* Return error if less than
                                    this amount is transferred */