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Commit c829c394 authored by James Smart's avatar James Smart Committed by James Bottomley
Browse files

[SCSI] FC transport : Avoid device offline cases by stalling aborts until device unblocked 



This moves the eh_timed_out functionality from the scsi_host_template
to the transport_template. Given that this is now a transport function,
the EH_RESET_TIMER case no longer caps the timer reschedulings. The
transport guarantees that this is not an infinite condition.

Signed-off-by: default avatarJames Bottomley <James.Bottomley@SteelEye.com>
parent ce313db2

drivers/scsi/scsi_error.c

+3 −6
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ 
#include <scsi/scsi_dbg.h>

#include <scsi/scsi_device.h>

#include <scsi/scsi_eh.h>

#include <scsi/scsi_transport.h>

#include <scsi/scsi_host.h>

#include <scsi/scsi_ioctl.h>

#include <scsi/scsi_request.h>
@@ -163,16 +164,12 @@ void scsi_times_out(struct scsi_cmnd *scmd) 
{

	scsi_log_completion(scmd, TIMEOUT_ERROR);



	if (scmd->device->host->hostt->eh_timed_out)

		switch (scmd->device->host->hostt->eh_timed_out(scmd)) {

	if (scmd->device->host->transportt->eh_timed_out)

		switch (scmd->device->host->transportt->eh_timed_out(scmd)) {

		case EH_HANDLED:

			__scsi_done(scmd);

			return;

		case EH_RESET_TIMER:

			/* This allows a single retry even of a command

			 * with allowed == 0 */

			if (scmd->retries++ > scmd->allowed)

				break;

			scsi_add_timer(scmd, scmd->timeout_per_command,

				       scsi_times_out);

			return;

drivers/scsi/scsi_transport_fc.c

+37 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <scsi/scsi_host.h>

#include <scsi/scsi_transport.h>

#include <scsi/scsi_transport_fc.h>

#include <scsi/scsi_cmnd.h>

#include "scsi_priv.h"



/*
@@ -1090,6 +1091,40 @@ static int fc_rport_match(struct attribute_container *cont, 
}





/**

 * fc_timed_out - FC Transport I/O timeout intercept handler

 *

 * @scmd:	The SCSI command which timed out

 *

 * This routine protects against error handlers getting invoked while a

 * rport is in a blocked state, typically due to a temporarily loss of

 * connectivity. If the error handlers are allowed to proceed, requests

 * to abort i/o, reset the target, etc will likely fail as there is no way

 * to communicate with the device to perform the requested function. These

 * failures may result in the midlayer taking the device offline, requiring

 * manual intervention to restore operation.

 *

 * This routine, called whenever an i/o times out, validates the state of

 * the underlying rport. If the rport is blocked, it returns

 * EH_RESET_TIMER, which will continue to reschedule the timeout.

 * Eventually, either the device will return, or devloss_tmo will fire,

 * and when the timeout then fires, it will be handled normally.

 * If the rport is not blocked, normal error handling continues.

 *

 * Notes:

 *	This routine assumes no locks are held on entry.

 **/

static enum scsi_eh_timer_return

fc_timed_out(struct scsi_cmnd *scmd)

{

	struct fc_rport *rport = starget_to_rport(scsi_target(scmd->device));



	if (rport->port_state == FC_PORTSTATE_BLOCKED)

		return EH_RESET_TIMER;



	return EH_NOT_HANDLED;

}



/*

 * Must be called with shost->host_lock held

 */
@@ -1146,6 +1181,8 @@ fc_attach_transport(struct fc_function_template *ft) 
	/* Transport uses the shost workq for scsi scanning */

	i->t.create_work_queue = 1;



	i->t.eh_timed_out = fc_timed_out;



	i->t.user_scan = fc_user_scan;

	

	/*

include/scsi/scsi_host.h

+0 −14
Original line number Diff line number Diff line
@@ -146,20 +146,6 @@ struct scsi_host_template { 
	int (* eh_bus_reset_handler)(struct scsi_cmnd *);

	int (* eh_host_reset_handler)(struct scsi_cmnd *);



	/*

	 * This is an optional routine to notify the host that the scsi

	 * timer just fired.  The returns tell the timer routine what to

	 * do about this:

	 *

	 * EH_HANDLED:		I fixed the error, please complete the command

	 * EH_RESET_TIMER:	I need more time, reset the timer and

	 *			begin counting again

	 * EH_NOT_HANDLED	Begin normal error recovery

	 *

	 * Status: OPTIONAL

	 */

	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);



	/*

	 * Before the mid layer attempts to scan for a new device where none

	 * currently exists, it will call this entry in your driver.  Should

include/scsi/scsi_transport.h

+11 −0
Original line number Diff line number Diff line
@@ -48,6 +48,17 @@ struct scsi_transport_template { 
	 * True if the transport wants to use a host-based work-queue

	 */

	unsigned int create_work_queue : 1;



	/*

	 * This is an optional routine that allows the transport to become

	 * involved when a scsi io timer fires. The return value tells the

	 * timer routine how to finish the io timeout handling:

	 * EH_HANDLED:		I fixed the error, please complete the command

	 * EH_RESET_TIMER:	I need more time, reset the timer and

	 *			begin counting again

	 * EH_NOT_HANDLED	Begin normal error recovery

	 */

	enum scsi_eh_timer_return (* eh_timed_out)(struct scsi_cmnd *);

};



#define transport_class_to_shost(tc) \