[SCSI] Fix thread termination for the SCSI error handle

From: 	Alan Stern <stern@rowland.harvard.edu>

This patch (as561) fixes the error handler's thread-exit code.  The
kthread_stop call won't wake the thread from a down_interruptible, so
the patch gets rid of the semaphore and simply does

        set_current_state(TASK_INTERRUPTIBLE);

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Modified to simplify the termination loop and correct the sleep condition.

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

diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index af589fa..ad53421 100644 (file)
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -50,7 +50,7 @@
 void scsi_eh_wakeup(struct Scsi_Host *shost)
 {
        if (shost->host_busy == shost->host_failed) {
-               up(shost->eh_wait);
+               wake_up_process(shost->ehandler);
                SCSI_LOG_ERROR_RECOVERY(5,
                                printk("Waking error handler thread\n"));
        }
@@ -70,7 +70,7 @@ int scsi_eh_scmd_add(struct scsi_cmnd *scmd, int eh_flag)
        unsigned long flags;
        int ret = 0;
 
-       if (shost->eh_wait == NULL)
+       if (!shost->ehandler)
                return 0;
 
        spin_lock_irqsave(shost->host_lock, flags);
@@ -1591,40 +1591,31 @@ int scsi_error_handler(void *data)
 {
        struct Scsi_Host *shost = (struct Scsi_Host *) data;
        int rtn;
-       DECLARE_MUTEX_LOCKED(sem);
 
        current->flags |= PF_NOFREEZE;
-       shost->eh_wait = &sem;
 
+       
        /*
-        * Wake up the thread that created us.
+        * Note - we always use TASK_INTERRUPTIBLE even if the module
+        * was loaded as part of the kernel.  The reason is that
+        * UNINTERRUPTIBLE would cause this thread to be counted in
+        * the load average as a running process, and an interruptible
+        * wait doesn't.
         */
-       SCSI_LOG_ERROR_RECOVERY(3, printk("Wake up parent of"
-                                         " scsi_eh_%d\n",shost->host_no));
-
-       while (1) {
-               /*
-                * If we get a signal, it means we are supposed to go
-                * away and die.  This typically happens if the user is
-                * trying to unload a module.
-                */
-               SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
-                                                 " scsi_eh_%d"
-                                                 " sleeping\n",shost->host_no));
-
-               /*
-                * Note - we always use down_interruptible with the semaphore
-                * even if the module was loaded as part of the kernel.  The
-                * reason is that down() will cause this thread to be counted
-                * in the load average as a running process, and down
-                * interruptible doesn't.  Given that we need to allow this
-                * thread to die if the driver was loaded as a module, using
-                * semaphores isn't unreasonable.
-                */
-               down_interruptible(&sem);
-               if (kthread_should_stop())
-                       break;
+       set_current_state(TASK_INTERRUPTIBLE);
+       while (!kthread_should_stop()) {
+               if (shost->host_failed == 0 ||
+                   shost->host_failed != shost->host_busy) {
+                       SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
+                                                         " scsi_eh_%d"
+                                                         " sleeping\n",
+                                                         shost->host_no));
+                       schedule();
+                       set_current_state(TASK_INTERRUPTIBLE);
+                       continue;
+               }
 
+               __set_current_state(TASK_RUNNING);
                SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler"
                                                  " scsi_eh_%d waking"
                                                  " up\n",shost->host_no));
@@ -1651,7 +1642,7 @@ int scsi_error_handler(void *data)
                 * which are still online.
                 */
                scsi_restart_operations(shost);
-
+               set_current_state(TASK_INTERRUPTIBLE);
        }
 
        SCSI_LOG_ERROR_RECOVERY(1, printk("Error handler scsi_eh_%d"
@@ -1660,7 +1651,7 @@ int scsi_error_handler(void *data)
        /*
         * Make sure that nobody tries to wake us up again.
         */
-       shost->eh_wait = NULL;
+       shost->ehandler = NULL;
        return 0;
 }
 

diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 540369f..69313ba 100644 (file)
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -467,8 +467,6 @@ struct Scsi_Host {
 
        struct list_head        eh_cmd_q;
        struct task_struct    * ehandler;  /* Error recovery thread. */
-       struct semaphore      * eh_wait;   /* The error recovery thread waits
-                                             on this. */
        struct semaphore      * eh_action; /* Wait for specific actions on the
                                           host. */
        unsigned int            eh_active:1; /* Indicates the eh thread is awake and active if