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Commit 3ed7a470 authored by James Bottomley's avatar James Bottomley
Browse files

[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: default avatarAlan Stern <stern@rowland.harvard.edu>

Modified to simplify the termination loop and correct the sleep condition.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent 939647ee

drivers/scsi/scsi_error.c

+23 −32
Original line number Diff line number Diff line
@@ -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.

	 */

	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.

	 * 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.

	 */

	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));



		/*

		 * 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;

							  " 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;

}

include/scsi/scsi_host.h

+0 −2
Original line number Diff line number Diff line
@@ -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