On Tue, 13 Sep 2005, Rolf Eike Beer wrote:
> Looks like someone has to build a waitqueue to fix this.
Tell me what you think of this patch. I'm not sure whether that
condition, host_busy == host_failed, is correct for the call to
wait_event_interruptible.
Alan Stern
Index: usb-2.6/drivers/scsi/scsi_error.c
===================================================================
--- usb-2.6.orig/drivers/scsi/scsi_error.c
+++ usb-2.6/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(&shost->eh_wait);
SCSI_LOG_ERROR_RECOVERY(5,
printk("Waking error handler thread\n"));
}
@@ -69,7 +69,7 @@ int scsi_eh_scmd_add(struct scsi_cmnd *s
struct Scsi_Host *shost = scmd->device->host;
unsigned long flags;
- if (shost->eh_wait == NULL)
+ if (shost->eh_alive == 0) /* Not 100% reliable */
return 0;
spin_lock_irqsave(shost->host_lock, flags);
@@ -1582,37 +1582,24 @@ 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.
- */
- 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);
+ * Note - we always use wait_event_interruptible even if
+ * the module was loaded as part of the kernel. The reason
+ * is that wait_event() will cause this thread to be counted
+ * in the load average as a running process, and an
+ * interruptible wait doesn't.
+ */
+ wait_event_interruptible(shost->eh_wait,
+ shost->host_busy == shost->host_failed ||
+ kthread_should_stop());
if (kthread_should_stop())
break;
@@ -1651,7 +1638,7 @@ int scsi_error_handler(void *data)
/*
* Make sure that nobody tries to wake us up again.
*/
- shost->eh_wait = NULL;
+ shost->eh_alive = 0;
return 0;
}
Index: usb-2.6/include/scsi/scsi_host.h
===================================================================
--- usb-2.6.orig/include/scsi/scsi_host.h
+++ usb-2.6/include/scsi/scsi_host.h
@@ -465,10 +465,11 @@ 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
+ wait_queue_head_t eh_wait; /* The error recovery thread waits
on this. */
struct semaphore * eh_action; /* Wait for specific actions on the
host. */
+ unsigned int eh_alive:1;
unsigned int eh_active:1; /* Indicates the eh thread is awake and active if
this is true. */
wait_queue_head_t host_wait;
Index: usb-2.6/drivers/scsi/hosts.c
===================================================================
--- usb-2.6.orig/drivers/scsi/hosts.c
+++ usb-2.6/drivers/scsi/hosts.c
@@ -285,6 +285,7 @@ struct Scsi_Host *scsi_host_alloc(struct
INIT_LIST_HEAD(&shost->__targets);
INIT_LIST_HEAD(&shost->eh_cmd_q);
INIT_LIST_HEAD(&shost->starved_list);
+ init_waitqueue_head(&shost->eh_wait);
init_waitqueue_head(&shost->host_wait);
init_MUTEX(&shost->scan_mutex);
@@ -368,6 +369,7 @@ struct Scsi_Host *scsi_host_alloc(struct
rval = PTR_ERR(shost->ehandler);
goto fail_destroy_freelist;
}
+ shost->eh_alive = 1;
scsi_proc_hostdir_add(shost->hostt);
return shost;
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