[SCSI] fc_transport: fix sysfs deadlock on vport delete

When the vport attribute "delete" is used to delete the vport, sysfs
deadlocks waiting for the write to complete, which is waiting for the
sysfs teardown to complete. Moved this effort to a work_q element.

Took the opportunity to make some other cosmetic changes:
 - removed tabs in Doc file - replaced with expanded spaces
 - minor copyright text and author text updates
 - removed a bunch of trailing whitespace

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

1 files changed, 35 insertions, 24 deletions

diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c
index 217651468115..4953f0dca029 100644
--- a/drivers/scsi/scsi_transport_fc.c
+++ b/drivers/scsi/scsi_transport_fc.c
@@ -1,4 +1,4 @@
-/* 
+/*
  *  FiberChannel transport specific attributes exported to sysfs.
  *
  *  Copyright (c) 2003 Silicon Graphics, Inc.  All rights reserved.
@@ -22,6 +22,7 @@
  *  Copyright (C) 2004-2007   James Smart, Emulex Corporation
  *    Rewrite for host, target, device, and remote port attributes,
  *    statistics, and service functions...
+ *    Add vports, etc
  *
  */
 #include <linux/module.h>
@@ -37,6 +38,7 @@
 #include "scsi_priv.h"
 
 static int fc_queue_work(struct Scsi_Host *, struct work_struct *);
+static void fc_vport_sched_delete(struct work_struct *work);
 
 /*
  * This is a temporary carrier for creating a vport. It will eventually
@@ -377,7 +379,7 @@ static int fc_host_setup(struct transport_container *tc, struct device *dev,
         struct Scsi_Host *shost = dev_to_shost(dev);
         struct fc_host_attrs *fc_host = shost_to_fc_host(shost);
 
-        /* 
+        /*
          * Set default values easily detected by the midlayer as
          * failure cases.  The scsi lldd is responsible for initializing
          * all transport attributes to valid values per host.
@@ -1198,12 +1200,9 @@ store_fc_vport_delete(struct class_device *cdev, const char *buf,
                            size_t count)
 {
         struct fc_vport *vport = transport_class_to_vport(cdev);
-        int stat;
-
-        stat = fc_vport_terminate(vport);
-        if (stat)
-                return stat;
+        struct Scsi_Host *shost = vport_to_shost(vport);
 
+        fc_queue_work(shost, &vport->vport_delete_work);
         return count;
 }
 static FC_CLASS_DEVICE_ATTR(vport, vport_delete, S_IWUSR,
@@ -1996,7 +1995,7 @@ fc_attach_transport(struct fc_function_template *ft)
         i->t.eh_timed_out = fc_timed_out;
 
         i->t.user_scan = fc_user_scan;
-        
+
         /*
          * Setup SCSI Target Attributes.
          */
@@ -2215,23 +2214,12 @@ fc_remove_host(struct Scsi_Host *shost)
         struct workqueue_struct *work_q;
         struct fc_host_attrs *fc_host = shost_to_fc_host(shost);
         unsigned long flags;
-        int stat;
 
         spin_lock_irqsave(shost->host_lock, flags);
 
         /* Remove any vports */
-        list_for_each_entry_safe(vport, next_vport, &fc_host->vports, peers) {
-                spin_unlock_irqrestore(shost->host_lock, flags);
-                /* this must be called synchronously */
-                stat = fc_vport_terminate(vport);
-                spin_lock_irqsave(shost->host_lock, flags);
-                if (stat)
-                        dev_printk(KERN_ERR, vport->dev.parent,
-                                "%s: %s could not be deleted created via "
-                                "shost%d channel %d\n", __FUNCTION__,
-                                vport->dev.bus_id, vport->shost->host_no,
-                                vport->channel);
-        }
+        list_for_each_entry_safe(vport, next_vport, &fc_host->vports, peers)
+                fc_queue_work(shost, &vport->vport_delete_work);
 
         /* Remove any remote ports */
         list_for_each_entry_safe(rport, next_rport,
@@ -2308,7 +2296,7 @@ fc_rport_final_delete(struct work_struct *work)
         unsigned long flags;
 
         /*
-         * if a scan is pending, flush the SCSI Host work_q so that 
+         * if a scan is pending, flush the SCSI Host work_q so that
          * that we can reclaim the rport scan work element.
          */
         if (rport->flags & FC_RPORT_SCAN_PENDING)
@@ -2858,7 +2846,7 @@ EXPORT_SYMBOL(fc_remote_port_rolechg);
  * fc_timeout_deleted_rport - Timeout handler for a deleted remote port,
  *                      which we blocked, and has now failed to return
  *                      in the allotted time.
- * 
+ *
  * @work:       rport target that failed to reappear in the allotted time.
  **/
 static void
@@ -3061,6 +3049,7 @@ fc_vport_create(struct Scsi_Host *shost, int channel, struct device *pdev,
         vport->shost = shost;
         vport->channel = channel;
         vport->flags = FC_VPORT_CREATING;
+        INIT_WORK(&vport->vport_delete_work, fc_vport_sched_delete);
 
         spin_lock_irqsave(shost->host_lock, flags);
 
@@ -3207,8 +3196,30 @@ fc_vport_terminate(struct fc_vport *vport)
 }
 EXPORT_SYMBOL(fc_vport_terminate);
 
+/**
+ * fc_vport_sched_delete - workq-based delete request for a vport
+ *
+ * @work:       vport to be deleted.
+ **/
+static void
+fc_vport_sched_delete(struct work_struct *work)
+{
+        struct fc_vport *vport =
+                container_of(work, struct fc_vport, vport_delete_work);
+        int stat;
+
+        stat = fc_vport_terminate(vport);
+        if (stat)
+                dev_printk(KERN_ERR, vport->dev.parent,
+                        "%s: %s could not be deleted created via "
+                        "shost%d channel %d - error %d\n", __FUNCTION__,
+                        vport->dev.bus_id, vport->shost->host_no,
+                        vport->channel, stat);
+}
+
 
-MODULE_AUTHOR("Martin Hicks");
+/* Original Author:  Martin Hicks */
+MODULE_AUTHOR("James Smart");
 MODULE_DESCRIPTION("FC Transport Attributes");
 MODULE_LICENSE("GPL");