[Resend PATCH 2/3] scsi:stex.c Add hotplug support

[Charles Chiou <ch1102chiou@gmail.com>]

 From 60e14c245c18cbe0300cfa244334e2850a52a381 Mon Sep 17 00:00:00 2001
From: Charles <charles.chiou@tw.promise.com>
Date: Wed, 2 Sep 2015 20:48:55 +0800
Subject: [PATCH 2/3] scsi:stex.c Add hotplug support

1. Add hotplug support. Pegasus support surprise removal. To this end, I
     use return_abnormal_state function to return DID_NO_CONNECT for all
        commands which sent to driver.

2. Remove stex_hba_stop in stex_remove because we cannot send command to
     device after hotplug.

3. Add new device status:  MU_STATE_STOP, MU_STATE_NOCONNECT,
     MU_STATE_STOP. MU_STATE_STOP is currently not referenced.
     MU_STATE_NOCONNECT represent that device is plugged out from the host.

4. Use return_abnormal_function() to substitute part of code in 
stex_do_reset.

V2: N/A

Signed-off-by: Charles Chiou <charles.chiou@tw.promise.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>

---
   drivers/scsi/stex.c | 53 
++++++++++++++++++++++++++++++++++-------------------
   1 file changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/scsi/stex.c b/drivers/scsi/stex.c
index 0c93f1f..4ef0c80 100644
--- a/drivers/scsi/stex.c
+++ b/drivers/scsi/stex.c
@@ -83,6 +83,8 @@ enum {
       MU_STATE_STARTED            = 2,
       MU_STATE_RESETTING            = 3,
       MU_STATE_FAILED                = 4,
+    MU_STATE_STOP                = 5,
+    MU_STATE_NOCONNECT            = 6,

       MU_MAX_DELAY                = 120,
       MU_HANDSHAKE_SIGNATURE            = 0x55aaaa55,
@@ -544,6 +546,27 @@ stex_ss_send_cmd(struct st_hba *hba, struct req_msg 
*req,
u16 tag)
       readl(hba->mmio_base + YH2I_REQ); /* flush */
   }

+static void return_abnormal_state(struct st_hba *hba, int status)
+{
+    struct st_ccb *ccb;
+    unsigned long flags;
+    u16 tag;
+
+    spin_lock_irqsave(hba->host->host_lock, flags);
+    for (tag = 0; tag < hba->host->can_queue; tag++) {
+        ccb = &hba->ccb[tag];
+        if (ccb->req == NULL)
+            continue;
+        ccb->req = NULL;
+        if (ccb->cmd) {
+            scsi_dma_unmap(ccb->cmd);
+            ccb->cmd->result = status << 16;
+            ccb->cmd->scsi_done(ccb->cmd);
+            ccb->cmd = NULL;
+        }
+    }
+    spin_unlock_irqrestore(hba->host->host_lock, flags);
+}
   static int
   stex_slave_config(struct scsi_device *sdev)
   {
@@ -567,8 +590,12 @@ stex_queuecommand_lck(struct scsi_cmnd *cmd, void
(*done)(struct scsi_cmnd *))
       id = cmd->device->id;
       lun = cmd->device->lun;
       hba = (struct st_hba *) &host->hostdata[0];
-
-    if (unlikely(hba->mu_status == MU_STATE_RESETTING))
+    if (hba->mu_status == MU_STATE_NOCONNECT) {
+        cmd->result = DID_NO_CONNECT;
+        done(cmd);
+        return 0;
+    }
+    if (unlikely(hba->mu_status != MU_STATE_STARTED))
           return SCSI_MLQUEUE_HOST_BUSY;

       switch (cmd->cmnd[0]) {
@@ -1267,10 +1294,8 @@ static void stex_ss_reset(struct st_hba *hba)

   static int stex_do_reset(struct st_hba *hba)
   {
-    struct st_ccb *ccb;
       unsigned long flags;
       unsigned int mu_status = MU_STATE_RESETTING;
-    u16 tag;

       spin_lock_irqsave(hba->host->host_lock, flags);
       if (hba->mu_status == MU_STATE_STARTING) {
@@ -1304,20 +1329,8 @@ static int stex_do_reset(struct st_hba *hba)
       else if (hba->cardtype == st_yel)
           stex_ss_reset(hba);

-    spin_lock_irqsave(hba->host->host_lock, flags);
-    for (tag = 0; tag < hba->host->can_queue; tag++) {
-        ccb = &hba->ccb[tag];
-        if (ccb->req == NULL)
-            continue;
-        ccb->req = NULL;
-        if (ccb->cmd) {
-            scsi_dma_unmap(ccb->cmd);
-            ccb->cmd->result = DID_RESET << 16;
-            ccb->cmd->scsi_done(ccb->cmd);
-            ccb->cmd = NULL;
-        }
-    }
-    spin_unlock_irqrestore(hba->host->host_lock, flags);
+
+    return_abnormal_state(hba, DID_RESET);

       if (stex_handshake(hba) == 0)
           return 0;
@@ -1786,9 +1799,11 @@ static void stex_remove(struct pci_dev *pdev)
   {
       struct st_hba *hba = pci_get_drvdata(pdev);

+    hba->mu_status = MU_STATE_NOCONNECT;
+    return_abnormal_state(hba, DID_NO_CONNECT);
       scsi_remove_host(hba->host);

-    stex_hba_stop(hba);
+    scsi_block_requests(hba->host);

       stex_hba_free(hba);