This patch changes the way the IBM vSCSI server driver manages its
Command/Response Queue (CRQ).  We used to register the CRQ with phyp at
probe time.  Now we wait until tpg_enable_store.  Similarly, when
tpg_enable_store is called to "disable" (i.e. the stored value is 0),
we unregister the queue with phyp.

One consquence to this is that we have no need for the PART_UP_WAIT_ENAB
state, since we can't get an Init Message from the client in our CRQ if
we're waiting to be enabled, since we haven't registered the queue yet.

Signed-off-by: Michael Cyr <mike...@us.ibm.com>
Signed-off-by: Bryant G. Ly <bryan...@linux.vnet.ibm.com>
---
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c | 224 ++++++-------------------------
 drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h |   2 -
 2 files changed, 38 insertions(+), 188 deletions(-)

diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c 
b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
index 01a430c..2ce1d73 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.c
@@ -61,8 +61,6 @@ static long ibmvscsis_parse_command(struct scsi_info *vscsi,
 
 static void ibmvscsis_adapter_idle(struct scsi_info *vscsi);
 
-static void ibmvscsis_reset_queue(struct scsi_info *vscsi, uint new_state);
-
 static void ibmvscsis_determine_resid(struct se_cmd *se_cmd,
                                      struct srp_rsp *rsp)
 {
@@ -417,7 +415,6 @@ static void ibmvscsis_disconnect(struct work_struct *work)
                                               proc_work);
        u16 new_state;
        bool wait_idle = false;
-       long rc = ADAPT_SUCCESS;
 
        spin_lock_bh(&vscsi->intr_lock);
        new_state = vscsi->new_state;
@@ -470,30 +467,12 @@ static void ibmvscsis_disconnect(struct work_struct *work)
                        vscsi->state = new_state;
                break;
 
-       /*
-        * If this is a transition into an error state.
-        * a client is attempting to establish a connection
-        * and has violated the RPA protocol.
-        * There can be nothing pending on the adapter although
-        * there can be requests in the command queue.
-        */
        case WAIT_ENABLED:
-       case PART_UP_WAIT_ENAB:
                switch (new_state) {
+               /* should never happen */
                case ERR_DISCONNECT:
-                       vscsi->flags |= RESPONSE_Q_DOWN;
-                       vscsi->state = new_state;
-                       vscsi->flags &= ~(SCHEDULE_DISCONNECT |
-                                         DISCONNECT_SCHEDULED);
-                       ibmvscsis_free_command_q(vscsi);
-                       break;
                case ERR_DISCONNECT_RECONNECT:
-                       ibmvscsis_reset_queue(vscsi, WAIT_ENABLED);
-                       break;
-
-               /* should never happen */
                case WAIT_IDLE:
-                       rc = ERROR;
                        dev_err(&vscsi->dev, "disconnect: invalid state %d for 
WAIT_IDLE\n",
                                vscsi->state);
                        break;
@@ -630,7 +609,6 @@ static void ibmvscsis_post_disconnect(struct scsi_info 
*vscsi, uint new_state,
                        break;
 
                case WAIT_ENABLED:
-               case PART_UP_WAIT_ENAB:
                case WAIT_IDLE:
                case WAIT_CONNECTION:
                case CONNECTED:
@@ -675,7 +653,6 @@ static long ibmvscsis_handle_init_compl_msg(struct 
scsi_info *vscsi)
        case SRP_PROCESSING:
        case CONNECTED:
        case WAIT_ENABLED:
-       case PART_UP_WAIT_ENAB:
        default:
                rc = ERROR;
                dev_err(&vscsi->dev, "init_msg: invalid state %d to get init 
compl msg\n",
@@ -698,10 +675,6 @@ static long ibmvscsis_handle_init_msg(struct scsi_info 
*vscsi)
        long rc = ADAPT_SUCCESS;
 
        switch (vscsi->state) {
-       case WAIT_ENABLED:
-               vscsi->state = PART_UP_WAIT_ENAB;
-               break;
-
        case WAIT_CONNECTION:
                rc = ibmvscsis_send_init_message(vscsi, INIT_COMPLETE_MSG);
                switch (rc) {
@@ -737,7 +710,7 @@ static long ibmvscsis_handle_init_msg(struct scsi_info 
*vscsi)
        case UNCONFIGURING:
                break;
 
-       case PART_UP_WAIT_ENAB:
+       case WAIT_ENABLED:
        case CONNECTED:
        case SRP_PROCESSING:
        case WAIT_IDLE:
@@ -800,11 +773,10 @@ static long ibmvscsis_init_msg(struct scsi_info *vscsi, 
struct viosrp_crq *crq)
 /**
  * ibmvscsis_establish_new_q() - Establish new CRQ queue
  * @vscsi:     Pointer to our adapter structure
- * @new_state: New state being established after resetting the queue
  *
  * Must be called with interrupt lock held.
  */
-static long ibmvscsis_establish_new_q(struct scsi_info *vscsi, uint new_state)
+static long ibmvscsis_establish_new_q(struct scsi_info *vscsi)
 {
        long rc = ADAPT_SUCCESS;
        uint format;
@@ -816,19 +788,19 @@ static long ibmvscsis_establish_new_q(struct scsi_info 
*vscsi, uint new_state)
 
        rc = vio_enable_interrupts(vscsi->dma_dev);
        if (rc) {
-               pr_warn("reset_queue: failed to enable interrupts, rc %ld\n",
+               pr_warn("establish_new_q: failed to enable interrupts, rc 
%ld\n",
                        rc);
                return rc;
        }
 
        rc = ibmvscsis_check_init_msg(vscsi, &format);
        if (rc) {
-               dev_err(&vscsi->dev, "reset_queue: check_init_msg failed, rc 
%ld\n",
+               dev_err(&vscsi->dev, "establish_new_q: check_init_msg failed, 
rc %ld\n",
                        rc);
                return rc;
        }
 
-       if (format == UNUSED_FORMAT && new_state == WAIT_CONNECTION) {
+       if (format == UNUSED_FORMAT) {
                rc = ibmvscsis_send_init_message(vscsi, INIT_MSG);
                switch (rc) {
                case H_SUCCESS:
@@ -846,6 +818,8 @@ static long ibmvscsis_establish_new_q(struct scsi_info 
*vscsi, uint new_state)
                        rc = H_HARDWARE;
                        break;
                }
+       } else if (format == INIT_MSG) {
+               rc = ibmvscsis_handle_init_msg(vscsi);
        }
 
        return rc;
@@ -854,7 +828,6 @@ static long ibmvscsis_establish_new_q(struct scsi_info 
*vscsi, uint new_state)
 /**
  * ibmvscsis_reset_queue() - Reset CRQ Queue
  * @vscsi:     Pointer to our adapter structure
- * @new_state: New state to establish after resetting the queue
  *
  * This function calls h_free_q and then calls h_reg_q and does all
  * of the bookkeeping to get us back to where we can communicate.
@@ -871,7 +844,7 @@ static long ibmvscsis_establish_new_q(struct scsi_info 
*vscsi, uint new_state)
  * EXECUTION ENVIRONMENT:
  *     Process environment, called with interrupt lock held
  */
-static void ibmvscsis_reset_queue(struct scsi_info *vscsi, uint new_state)
+static void ibmvscsis_reset_queue(struct scsi_info *vscsi)
 {
        int bytes;
        long rc = ADAPT_SUCCESS;
@@ -884,19 +857,18 @@ static void ibmvscsis_reset_queue(struct scsi_info 
*vscsi, uint new_state)
                vscsi->rsp_q_timer.timer_pops = 0;
                vscsi->debit = 0;
                vscsi->credit = 0;
-               vscsi->state = new_state;
+               vscsi->state = WAIT_CONNECTION;
                vio_enable_interrupts(vscsi->dma_dev);
        } else {
                rc = ibmvscsis_free_command_q(vscsi);
                if (rc == ADAPT_SUCCESS) {
-                       vscsi->state = new_state;
+                       vscsi->state = WAIT_CONNECTION;
 
                        bytes = vscsi->cmd_q.size * PAGE_SIZE;
                        rc = h_reg_crq(vscsi->dds.unit_id,
                                       vscsi->cmd_q.crq_token, bytes);
                        if (rc == H_CLOSED || rc == H_SUCCESS) {
-                               rc = ibmvscsis_establish_new_q(vscsi,
-                                                              new_state);
+                               rc = ibmvscsis_establish_new_q(vscsi);
                        }
 
                        if (rc != ADAPT_SUCCESS) {
@@ -1015,10 +987,6 @@ static long ibmvscsis_trans_event(struct scsi_info *vscsi,
                                                   TRANS_EVENT));
                        break;
 
-               case PART_UP_WAIT_ENAB:
-                       vscsi->state = WAIT_ENABLED;
-                       break;
-
                case SRP_PROCESSING:
                        if ((vscsi->debit > 0) ||
                            !list_empty(&vscsi->schedule_q) ||
@@ -1219,15 +1187,18 @@ static void ibmvscsis_adapter_idle(struct scsi_info 
*vscsi)
 
        switch (vscsi->state) {
        case ERR_DISCONNECT_RECONNECT:
-               ibmvscsis_reset_queue(vscsi, WAIT_CONNECTION);
+               ibmvscsis_reset_queue(vscsi);
                pr_debug("adapter_idle, disc_rec: flags 0x%x\n", vscsi->flags);
                break;
 
        case ERR_DISCONNECT:
                ibmvscsis_free_command_q(vscsi);
-               vscsi->flags &= ~DISCONNECT_SCHEDULED;
+               vscsi->flags &= ~(SCHEDULE_DISCONNECT | DISCONNECT_SCHEDULED);
                vscsi->flags |= RESPONSE_Q_DOWN;
-               vscsi->state = ERR_DISCONNECTED;
+               if (vscsi->tport.enabled)
+                       vscsi->state = ERR_DISCONNECTED;
+               else
+                       vscsi->state = WAIT_ENABLED;
                pr_debug("adapter_idle, disc: flags 0x%x, state 0x%hx\n",
                         vscsi->flags, vscsi->state);
                break;
@@ -1772,8 +1743,8 @@ static void ibmvscsis_send_messages(struct scsi_info 
*vscsi)
                                        be64_to_cpu(msg_hi),
                                        be64_to_cpu(cmd->rsp.tag));
 
-                       pr_debug("send_messages: tag 0x%llx, rc %ld\n",
-                                be64_to_cpu(cmd->rsp.tag), rc);
+                       pr_debug("send_messages: cmd %p, tag 0x%llx, rc %ld\n",
+                                cmd, be64_to_cpu(cmd->rsp.tag), rc);
 
                        /* if all ok free up the command element resources */
                        if (rc == H_SUCCESS) {
@@ -2788,36 +2759,6 @@ static irqreturn_t ibmvscsis_interrupt(int dummy, void 
*data)
 }
 
 /**
- * ibmvscsis_check_q() - Helper function to Check Init Message Valid
- * @vscsi:     Pointer to our adapter structure
- *
- * Checks if a initialize message was queued by the initiatior
- * while the timing window was open.  This function is called from
- * probe after the CRQ is created and interrupts are enabled.
- * It would only be used by adapters who wait for some event before
- * completing the init handshake with the client.  For ibmvscsi, this
- * event is waiting for the port to be enabled.
- *
- * EXECUTION ENVIRONMENT:
- *     Process level only, interrupt lock held
- */
-static long ibmvscsis_check_q(struct scsi_info *vscsi)
-{
-       uint format;
-       long rc;
-
-       rc = ibmvscsis_check_init_msg(vscsi, &format);
-       if (rc)
-               ibmvscsis_post_disconnect(vscsi, ERR_DISCONNECT_RECONNECT, 0);
-       else if (format == UNUSED_FORMAT)
-               vscsi->state = WAIT_ENABLED;
-       else
-               vscsi->state = PART_UP_WAIT_ENAB;
-
-       return rc;
-}
-
-/**
  * ibmvscsis_enable_change_state() - Set new state based on enabled status
  * @vscsi:     Pointer to our adapter structure
  *
@@ -2828,77 +2769,19 @@ static long ibmvscsis_check_q(struct scsi_info *vscsi)
  */
 static long ibmvscsis_enable_change_state(struct scsi_info *vscsi)
 {
+       int bytes;
        long rc = ADAPT_SUCCESS;
 
-handle_state_change:
-       switch (vscsi->state) {
-       case WAIT_ENABLED:
-               rc = ibmvscsis_send_init_message(vscsi, INIT_MSG);
-               switch (rc) {
-               case H_SUCCESS:
-               case H_DROPPED:
-               case H_CLOSED:
-                       vscsi->state =  WAIT_CONNECTION;
-                       rc = ADAPT_SUCCESS;
-                       break;
-
-               case H_PARAMETER:
-                       break;
-
-               case H_HARDWARE:
-                       break;
-
-               default:
-                       vscsi->state = UNDEFINED;
-                       rc = H_HARDWARE;
-                       break;
-               }
-               break;
-       case PART_UP_WAIT_ENAB:
-               rc = ibmvscsis_send_init_message(vscsi, INIT_COMPLETE_MSG);
-               switch (rc) {
-               case H_SUCCESS:
-                       vscsi->state = CONNECTED;
-                       rc = ADAPT_SUCCESS;
-                       break;
-
-               case H_DROPPED:
-               case H_CLOSED:
-                       vscsi->state = WAIT_ENABLED;
-                       goto handle_state_change;
-
-               case H_PARAMETER:
-                       break;
-
-               case H_HARDWARE:
-                       break;
-
-               default:
-                       rc = H_HARDWARE;
-                       break;
-               }
-               break;
-
-       case WAIT_CONNECTION:
-       case WAIT_IDLE:
-       case SRP_PROCESSING:
-       case CONNECTED:
-               rc = ADAPT_SUCCESS;
-               break;
-               /* should not be able to get here */
-       case UNCONFIGURING:
-               rc = ERROR;
-               vscsi->state = UNDEFINED;
-               break;
+       bytes = vscsi->cmd_q.size * PAGE_SIZE;
+       rc = h_reg_crq(vscsi->dds.unit_id, vscsi->cmd_q.crq_token, bytes);
+       if (rc == H_CLOSED || rc == H_SUCCESS) {
+               vscsi->state = WAIT_CONNECTION;
+               rc = ibmvscsis_establish_new_q(vscsi);
+       }
 
-               /* driver should never allow this to happen */
-       case ERR_DISCONNECT:
-       case ERR_DISCONNECT_RECONNECT:
-       default:
-               dev_err(&vscsi->dev, "in invalid state %d during 
enable_change_state\n",
-                       vscsi->state);
-               rc = ADAPT_SUCCESS;
-               break;
+       if (rc != ADAPT_SUCCESS) {
+               vscsi->state = ERR_DISCONNECTED;
+               vscsi->flags |= RESPONSE_Q_DOWN;
        }
 
        return rc;
@@ -2918,7 +2801,6 @@ handle_state_change:
  */
 static long ibmvscsis_create_command_q(struct scsi_info *vscsi, int num_cmds)
 {
-       long rc = 0;
        int pages;
        struct vio_dev *vdev = vscsi->dma_dev;
 
@@ -2942,22 +2824,7 @@ static long ibmvscsis_create_command_q(struct scsi_info 
*vscsi, int num_cmds)
                return -ENOMEM;
        }
 
-       rc =  h_reg_crq(vscsi->dds.unit_id, vscsi->cmd_q.crq_token, PAGE_SIZE);
-       if (rc) {
-               if (rc == H_CLOSED) {
-                       vscsi->state = WAIT_ENABLED;
-                       rc = 0;
-               } else {
-                       dma_unmap_single(&vdev->dev, vscsi->cmd_q.crq_token,
-                                        PAGE_SIZE, DMA_BIDIRECTIONAL);
-                       free_page((unsigned long)vscsi->cmd_q.base_addr);
-                       rc = -ENODEV;
-               }
-       } else {
-               vscsi->state = WAIT_ENABLED;
-       }
-
-       return rc;
+       return 0;
 }
 
 /**
@@ -3487,31 +3354,12 @@ static int ibmvscsis_probe(struct vio_dev *vdev,
                goto destroy_WQ;
        }
 
-       spin_lock_bh(&vscsi->intr_lock);
-       vio_enable_interrupts(vdev);
-       if (rc) {
-               dev_err(&vscsi->dev, "enabling interrupts failed, rc %d\n", rc);
-               rc = -ENODEV;
-               spin_unlock_bh(&vscsi->intr_lock);
-               goto free_irq;
-       }
-
-       if (ibmvscsis_check_q(vscsi)) {
-               rc = ERROR;
-               dev_err(&vscsi->dev, "probe: check_q failed, rc %d\n", rc);
-               spin_unlock_bh(&vscsi->intr_lock);
-               goto disable_interrupt;
-       }
-       spin_unlock_bh(&vscsi->intr_lock);
+       vscsi->state = WAIT_ENABLED;
 
        dev_set_drvdata(&vdev->dev, vscsi);
 
        return 0;
 
-disable_interrupt:
-       vio_disable_interrupts(vdev);
-free_irq:
-       free_irq(vdev->irq, vscsi);
 destroy_WQ:
        destroy_workqueue(vscsi->work_q);
 unmap_buf:
@@ -3905,18 +3753,22 @@ static ssize_t ibmvscsis_tpg_enable_store(struct 
config_item *item,
        }
 
        if (tmp) {
-               tport->enabled = true;
                spin_lock_bh(&vscsi->intr_lock);
+               tport->enabled = true;
                lrc = ibmvscsis_enable_change_state(vscsi);
                if (lrc)
                        pr_err("enable_change_state failed, rc %ld state %d\n",
                               lrc, vscsi->state);
                spin_unlock_bh(&vscsi->intr_lock);
        } else {
+               spin_lock_bh(&vscsi->intr_lock);
                tport->enabled = false;
+               /* This simulates the server going down */
+               ibmvscsis_post_disconnect(vscsi, ERR_DISCONNECT, 0);
+               spin_unlock_bh(&vscsi->intr_lock);
        }
 
-       pr_debug("tpg_enable_store, state %d\n", vscsi->state);
+       pr_debug("tpg_enable_store, tmp %ld, state %d\n", tmp, vscsi->state);
 
        return count;
 }
diff --git a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h 
b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
index 981a0c9..17e0ef4 100644
--- a/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
+++ b/drivers/scsi/ibmvscsi_tgt/ibmvscsi_tgt.h
@@ -204,8 +204,6 @@ struct scsi_info {
        struct list_head waiting_rsp;
 #define NO_QUEUE                    0x00
 #define WAIT_ENABLED                0X01
-       /* driver has received an initialize command */
-#define PART_UP_WAIT_ENAB           0x02
 #define WAIT_CONNECTION             0x04
        /* have established a connection */
 #define CONNECTED                   0x08
-- 
2.5.0

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