[SCSI] tgt: fix sesnse buffer problems

This patch simplify the way to notify LLDs of the command completion
and addresses the following sense buffer problems:

- can't handle both data and sense.
- forces user-space to use aligned sense buffer

tgt copies sense_data from userspace to cmnd->sense_buffer (if
necessary), maps user-space pages (if necessary) and then calls
host->transfer_response (host->transfer_data is removed).

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

6 files changed, 44 insertions, 133 deletions

diff --git a/drivers/scsi/ibmvscsi/ibmvstgt.c b/drivers/scsi/ibmvscsi/ibmvstgt.c
index 4368ca0e8270..a7fbd10817a0 100644
--- a/drivers/scsi/ibmvscsi/ibmvstgt.c
+++ b/drivers/scsi/ibmvscsi/ibmvstgt.c
@@ -273,23 +273,9 @@ static int ibmvstgt_rdma(struct scsi_cmnd *sc, struct scatterlist *sg, int nsg,
                 rest -= mlen;
         }
 out:
-
         return 0;
 }
 
-static int ibmvstgt_transfer_data(struct scsi_cmnd *sc,
-                                  void (*done)(struct scsi_cmnd *))
-{
-        struct iu_entry *iue = (struct iu_entry *) sc->SCp.ptr;
-        int err;
-
-        err = srp_transfer_data(sc, &vio_iu(iue)->srp.cmd, ibmvstgt_rdma, 1, 1);
-
-        done(sc);
-
-        return err;
-}
-
 static int ibmvstgt_cmd_done(struct scsi_cmnd *sc,
                              void (*done)(struct scsi_cmnd *))
 {
@@ -297,7 +283,11 @@ static int ibmvstgt_cmd_done(struct scsi_cmnd *sc,
         struct iu_entry *iue = (struct iu_entry *) sc->SCp.ptr;
         struct srp_target *target = iue->target;
 
-        dprintk("%p %p %x\n", iue, target, vio_iu(iue)->srp.cmd.cdb[0]);
+        dprintk("%p %p %x %u\n", iue, target, vio_iu(iue)->srp.cmd.cdb[0],
+                cmd->usg_sg);
+
+        if (sc->use_sg)
+                srp_transfer_data(sc, &vio_iu(iue)->srp.cmd, ibmvstgt_rdma, 1, 1);
 
         spin_lock_irqsave(&target->lock, flags);
         list_del(&iue->ilist);
@@ -794,7 +784,6 @@ static struct scsi_host_template ibmvstgt_sht = {
         .use_clustering         = DISABLE_CLUSTERING,
         .max_sectors            = DEFAULT_MAX_SECTORS,
         .transfer_response      = ibmvstgt_cmd_done,
-        .transfer_data          = ibmvstgt_transfer_data,
         .eh_abort_handler       = ibmvstgt_eh_abort_handler,
         .tsk_mgmt_response      = ibmvstgt_tsk_mgmt_response,
         .shost_attrs            = ibmvstgt_attrs,
diff --git a/drivers/scsi/scsi_tgt_if.c b/drivers/scsi/scsi_tgt_if.c
index 0e08817fdecf..ca22ddf81746 100644
--- a/drivers/scsi/scsi_tgt_if.c
+++ b/drivers/scsi/scsi_tgt_if.c
@@ -179,10 +179,12 @@ static int event_recv_msg(struct tgt_event *ev)
         switch (ev->hdr.type) {
         case TGT_UEVENT_CMD_RSP:
                 err = scsi_tgt_kspace_exec(ev->p.cmd_rsp.host_no,
-                                           ev->p.cmd_rsp.tag,
                                            ev->p.cmd_rsp.result,
-                                           ev->p.cmd_rsp.len,
+                                           ev->p.cmd_rsp.tag,
                                            ev->p.cmd_rsp.uaddr,
+                                           ev->p.cmd_rsp.len,
+                                           ev->p.cmd_rsp.sense_uaddr,
+                                           ev->p.cmd_rsp.sense_len,
                                            ev->p.cmd_rsp.rw);
                 break;
         case TGT_UEVENT_TSK_MGMT_RSP:
diff --git a/drivers/scsi/scsi_tgt_lib.c b/drivers/scsi/scsi_tgt_lib.c
index 47c29a98c922..dc8781a68d7c 100644
--- a/drivers/scsi/scsi_tgt_lib.c
+++ b/drivers/scsi/scsi_tgt_lib.c
@@ -47,9 +47,6 @@ struct scsi_tgt_cmd {
         struct list_head hash_list;
         struct request *rq;
         u64 tag;
-
-        void *buffer;
-        unsigned bufflen;
 };
 
 #define TGT_HASH_ORDER  4
@@ -330,10 +327,14 @@ static void scsi_tgt_cmd_done(struct scsi_cmnd *cmd)
         dprintk("cmd %p %lu\n", cmd, rq_data_dir(cmd->request));
 
         scsi_tgt_uspace_send_status(cmd, tcmd->tag);
+
+        if (cmd->request_buffer)
+                scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
+
         queue_work(scsi_tgtd, &tcmd->work);
 }
 
-static int __scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
+static int scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
 {
         struct Scsi_Host *shost = scsi_tgt_cmd_to_host(cmd);
         int err;
@@ -346,30 +347,12 @@ static int __scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
         case SCSI_MLQUEUE_DEVICE_BUSY:
                 return -EAGAIN;
         }
-
         return 0;
 }
 
-static void scsi_tgt_transfer_response(struct scsi_cmnd *cmd)
-{
-        struct scsi_tgt_cmd *tcmd = cmd->request->end_io_data;
-        int err;
-
-        err = __scsi_tgt_transfer_response(cmd);
-        if (!err)
-                return;
-
-        cmd->result = DID_BUS_BUSY << 16;
-        err = scsi_tgt_uspace_send_status(cmd, tcmd->tag);
-        if (err <= 0)
-                /* the eh will have to pick this up */
-                printk(KERN_ERR "Could not send cmd %p status\n", cmd);
-}
-
 static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 {
         struct request *rq = cmd->request;
-        struct scsi_tgt_cmd *tcmd = rq->end_io_data;
         int count;
 
         cmd->use_sg = rq->nr_phys_segments;
@@ -379,31 +362,28 @@ static int scsi_tgt_init_cmd(struct scsi_cmnd *cmd, gfp_t gfp_mask)
 
         cmd->request_bufflen = rq->data_len;
 
-        dprintk("cmd %p addr %p cnt %d %lu\n", cmd, tcmd->buffer, cmd->use_sg,
-                rq_data_dir(rq));
+        dprintk("cmd %p cnt %d %lu\n", cmd, cmd->use_sg, rq_data_dir(rq));
         count = blk_rq_map_sg(rq->q, rq, cmd->request_buffer);
         if (likely(count <= cmd->use_sg)) {
                 cmd->use_sg = count;
                 return 0;
         }
 
-        eprintk("cmd %p addr %p cnt %d\n", cmd, tcmd->buffer, cmd->use_sg);
+        eprintk("cmd %p cnt %d\n", cmd, cmd->use_sg);
         scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
         return -EINVAL;
 }
 
 /* TODO: test this crap and replace bio_map_user with new interface maybe */
 static int scsi_map_user_pages(struct scsi_tgt_cmd *tcmd, struct scsi_cmnd *cmd,
-                               int rw)
+                               unsigned long uaddr, unsigned int len, int rw)
 {
         struct request_queue *q = cmd->request->q;
         struct request *rq = cmd->request;
-        void *uaddr = tcmd->buffer;
-        unsigned int len = tcmd->bufflen;
         int err;
 
-        dprintk("%lx %u\n", (unsigned long) uaddr, len);
-        err = blk_rq_map_user(q, rq, uaddr, len);
+        dprintk("%lx %u\n", uaddr, len);
+        err = blk_rq_map_user(q, rq, (void *)uaddr, len);
         if (err) {
                 /*
                  * TODO: need to fixup sg_tablesize, max_segment_size,
@@ -430,45 +410,6 @@ unmap_rq:
         return err;
 }
 
-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;
-        int err;
-
-        /* should we free resources here on error ? */
-        if (cmd->result) {
-                err = scsi_tgt_uspace_send_status(cmd, tcmd->tag);
-                if (err <= 0)
-                        /* the tgt uspace eh will have to pick this up */
-                        printk(KERN_ERR "Could not send cmd %p status\n", cmd);
-                return;
-        }
-
-        dprintk("cmd %p request_bufflen %u bufflen %u\n",
-                cmd, cmd->request_bufflen, tcmd->bufflen);
-
-        scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len);
-        tcmd->buffer += cmd->request_bufflen;
-        scsi_tgt_transfer_response(cmd);
-}
-
-static int scsi_tgt_transfer_data(struct scsi_cmnd *cmd)
-{
-        int err;
-        struct Scsi_Host *host = scsi_tgt_cmd_to_host(cmd);
-
-        err = host->hostt->transfer_data(cmd, scsi_tgt_data_transfer_done);
-        switch (err) {
-                case SCSI_MLQUEUE_HOST_BUSY:
-                case SCSI_MLQUEUE_DEVICE_BUSY:
-                        return -EAGAIN;
-        default:
-                return 0;
-        }
-}
-
 static int scsi_tgt_copy_sense(struct scsi_cmnd *cmd, unsigned long uaddr,
                                 unsigned len)
 {
@@ -518,8 +459,9 @@ static struct request *tgt_cmd_hash_lookup(struct request_queue *q, u64 tag)
         return rq;
 }
 
-int scsi_tgt_kspace_exec(int host_no, u64 tag, int result, u32 len,
-                         unsigned long uaddr, u8 rw)
+int scsi_tgt_kspace_exec(int host_no, int result, u64 tag,
+                         unsigned long uaddr, u32 len, unsigned long sense_uaddr,
+                         u32 sense_len, u8 rw)
 {
         struct Scsi_Host *shost;
         struct scsi_cmnd *cmd;
@@ -564,36 +506,20 @@ int scsi_tgt_kspace_exec(int host_no, u64 tag, int result, u32 len,
          * in the request_* values
          */
         tcmd = cmd->request->end_io_data;
-        tcmd->buffer = (void *)uaddr;
-        tcmd->bufflen = len;
         cmd->result = result;
 
-        if (!tcmd->bufflen || cmd->request_buffer) {
-                err = __scsi_tgt_transfer_response(cmd);
-                goto done;
-        }
-
-        /*
-         * TODO: Do we need to handle case where request does not
-         * align with LLD.
-         */
-        err = scsi_map_user_pages(rq->end_io_data, cmd, rw);
-        if (err) {
-                eprintk("%p %d\n", cmd, err);
-                err = -EAGAIN;
-                goto done;
-        }
+        if (cmd->result == SAM_STAT_CHECK_CONDITION)
+                scsi_tgt_copy_sense(cmd, sense_uaddr, sense_len);
 
-        /* userspace failure */
-        if (cmd->result) {
-                if (status_byte(cmd->result) == CHECK_CONDITION)
-                        scsi_tgt_copy_sense(cmd, uaddr, len);
-                err = __scsi_tgt_transfer_response(cmd);
-                goto done;
+        if (len) {
+                err = scsi_map_user_pages(rq->end_io_data, cmd, uaddr, len, rw);
+                if (err) {
+                        eprintk("%p %d\n", cmd, err);
+                        err = -EAGAIN;
+                        goto done;
+                }
         }
-        /* ask the target LLD to transfer the data to the buffer */
-        err = scsi_tgt_transfer_data(cmd);
-
+        err = scsi_tgt_transfer_response(cmd);
 done:
         scsi_host_put(shost);
         return err;
diff --git a/drivers/scsi/scsi_tgt_priv.h b/drivers/scsi/scsi_tgt_priv.h
index 84488c51ff62..e9e6db1c417f 100644
--- a/drivers/scsi/scsi_tgt_priv.h
+++ b/drivers/scsi/scsi_tgt_priv.h
@@ -18,8 +18,9 @@ extern int scsi_tgt_if_init(void);
 extern int scsi_tgt_uspace_send_cmd(struct scsi_cmnd *cmd, struct scsi_lun *lun,
                                     u64 tag);
 extern int scsi_tgt_uspace_send_status(struct scsi_cmnd *cmd, u64 tag);
-extern int scsi_tgt_kspace_exec(int host_no, u64 tag, int result, u32 len,
-                                unsigned long uaddr, u8 rw);
+extern int scsi_tgt_kspace_exec(int host_no, int result, u64 tag,
+                                unsigned long uaddr, u32 len, unsigned long sense_uaddr,
+                                u32 sense_len, u8 rw);
 extern int scsi_tgt_uspace_send_tsk_mgmt(int host_no, int function, u64 tag,
                                          struct scsi_lun *scsilun, void *data);
 extern int scsi_tgt_kspace_tsk_mgmt(int host_no, u64 mid, int result);
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 7f1f411d07af..965b6b8ffec5 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -129,6 +129,11 @@ struct scsi_host_template {
          * the LLD. When the driver is finished processing the command
          * the done callback is invoked.
          *
+         * This is called to inform the LLD to transfer
+         * cmd->request_bufflen bytes. The cmd->use_sg speciefies the
+         * number of scatterlist entried in the command and
+         * cmd->request_buffer contains the scatterlist.
+         *
          * return values: see queuecommand
          *
          * If the LLD accepts the cmd, it should set the result to an
@@ -139,20 +144,6 @@ struct scsi_host_template {
         /* TODO: rename */
         int (* transfer_response)(struct scsi_cmnd *,
                                   void (*done)(struct scsi_cmnd *));
-        /*
-         * This is called to inform the LLD to transfer cmd->request_bufflen
-         * bytes of the cmd at cmd->offset in the cmd. The cmd->use_sg
-         * speciefies the number of scatterlist entried in the command
-         * and cmd->request_buffer contains the scatterlist.
-         *
-         * If the command cannot be processed in one transfer_data call
-         * becuase a scatterlist within the LLD's limits cannot be
-         * created then transfer_data will be called multiple times.
-         * It is initially called from process context, and later
-         * calls are from the interrup context.
-         */
-        int (* transfer_data)(struct scsi_cmnd *,
-                              void (*done)(struct scsi_cmnd *));
 
         /* Used as callback for the completion of task management request. */
         int (* tsk_mgmt_response)(u64 mid, int result);
diff --git a/include/scsi/scsi_tgt_if.h b/include/scsi/scsi_tgt_if.h
index 07d6e77ae895..4cf9dff29a2f 100644
--- a/include/scsi/scsi_tgt_if.h
+++ b/include/scsi/scsi_tgt_if.h
@@ -45,11 +45,13 @@ struct tgt_event {
                 /* user-> kernel */
                 struct {
                         int host_no;
-                        uint32_t len;
                         int result;
+                        aligned_u64 tag;
                         aligned_u64 uaddr;
+                        aligned_u64 sense_uaddr;
+                        uint32_t len;
+                        uint32_t sense_len;
                         uint8_t rw;
-                        aligned_u64 tag;
                 } cmd_rsp;
                 struct {
                         int host_no;