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Commit abd559b1 authored by Jody McIntyre's avatar Jody McIntyre Committed by Linus Torvalds
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[PATCH] sbp2: fix deadlocks and delays on device removal/rmmod 



Fixes for deadlocks of the ieee1394 and scsi subsystems and long delays in
futile error recovery attempts when SBP-2 devices are removed or drivers are
unloaded.

 - Complete commands quickly with DID_NO_CONNECT if the 1394 node is gone or if
   the 1394 low-level driver was unloaded.
 - Skip unnecessary work in the eh_abort_handler and eh_device_reset_handler if
   the node or 1394 low-level driver is gone.
 - Let scsi's high-level shut down gracefully when sbp2 is being unloaded or
   detached from the 1394 unit. A call to scsi_remove_device is added for this
   purpose, which requires us to store a scsi_device pointer.
 - scsi_device pointer is obtained from slave_alloc hook and cleared by
   slave_destroy. This avoids usage of the pointer after the scsi device was
   deleted e.g. by the user via scsi_mod's sysfs interface.

Signed-off-by: default avatarStefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: default avatarJody McIntyre <scjody@steamballoon.com>
Cc: Ben Collins <bcollins@debian.org>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 105d7b38

drivers/ieee1394/sbp2.c

+58 −38
Original line number Diff line number Diff line
@@ -596,6 +596,14 @@ static void sbp2util_mark_command_completed(struct scsi_id_instance_data *scsi_i 
	spin_unlock_irqrestore(&scsi_id->sbp2_command_orb_lock, flags);

}



/*

 * Is scsi_id valid? Is the 1394 node still present?

 */

static inline int sbp2util_node_is_available(struct scsi_id_instance_data *scsi_id)

{

	return scsi_id && scsi_id->ne && !scsi_id->ne->in_limbo;

}







/*********************************************
@@ -631,11 +639,23 @@ static int sbp2_remove(struct device *dev) 
{

	struct unit_directory *ud;

	struct scsi_id_instance_data *scsi_id;

	struct scsi_device *sdev;



	SBP2_DEBUG("sbp2_remove");



	ud = container_of(dev, struct unit_directory, device);

	scsi_id = ud->device.driver_data;

	if (!scsi_id)

		return 0;



	/* Trigger shutdown functions in scsi's highlevel. */

	if (scsi_id->scsi_host)

		scsi_unblock_requests(scsi_id->scsi_host);

	sdev = scsi_id->sdev;

	if (sdev) {

		scsi_id->sdev = NULL;

		scsi_remove_device(sdev);

	}



	sbp2_logout_device(scsi_id);

	sbp2_remove_device(scsi_id);
@@ -2473,37 +2493,26 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt, 
	struct scsi_id_instance_data *scsi_id =

		(struct scsi_id_instance_data *)SCpnt->device->host->hostdata[0];

	struct sbp2scsi_host_info *hi;

	int result = DID_NO_CONNECT << 16;



	SBP2_DEBUG("sbp2scsi_queuecommand");



	/*

	 * If scsi_id is null, it means there is no device in this slot,

	 * so we should return selection timeout.

	 */

	if (!scsi_id) {

		SCpnt->result = DID_NO_CONNECT << 16;

		done (SCpnt);

		return 0;

	}

	if (!sbp2util_node_is_available(scsi_id))

		goto done;



	hi = scsi_id->hi;



	if (!hi) {

		SBP2_ERR("sbp2scsi_host_info is NULL - this is bad!");

		SCpnt->result = DID_NO_CONNECT << 16;

		done (SCpnt);

		return(0);

		goto done;

	}



	/*

	 * Until we handle multiple luns, just return selection time-out

	 * to any IO directed at non-zero LUNs

	 */

	if (SCpnt->device->lun) {

		SCpnt->result = DID_NO_CONNECT << 16;

		done (SCpnt);

		return(0);

	}

	if (SCpnt->device->lun)

		goto done;



	/*

	 * Check for request sense command, and handle it here
@@ -2514,7 +2523,7 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt, 
		memcpy(SCpnt->request_buffer, SCpnt->sense_buffer, SCpnt->request_bufflen);

		memset(SCpnt->sense_buffer, 0, sizeof(SCpnt->sense_buffer));

		sbp2scsi_complete_command(scsi_id, SBP2_SCSI_STATUS_GOOD, SCpnt, done);

		return(0);

		return 0;

	}



	/*
@@ -2522,9 +2531,8 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt, 
	 */

	if (!hpsb_node_entry_valid(scsi_id->ne)) {

		SBP2_ERR("Bus reset in progress - rejecting command");

		SCpnt->result = DID_BUS_BUSY << 16;

		done (SCpnt);

		return(0);

		result = DID_BUS_BUSY << 16;

		goto done;

	}



	/*
@@ -2535,8 +2543,12 @@ static int sbp2scsi_queuecommand(struct scsi_cmnd *SCpnt, 
		sbp2scsi_complete_command(scsi_id, SBP2_SCSI_STATUS_SELECTION_TIMEOUT,

					  SCpnt, done);

	}

	return 0;



	return(0);

done:

	SCpnt->result = result;

	done(SCpnt);

	return 0;

}



/*
@@ -2683,14 +2695,27 @@ static void sbp2scsi_complete_command(struct scsi_id_instance_data *scsi_id, 
}





static int sbp2scsi_slave_alloc(struct scsi_device *sdev)

{

	((struct scsi_id_instance_data *)sdev->host->hostdata[0])->sdev = sdev;

	return 0;

}





static int sbp2scsi_slave_configure(struct scsi_device *sdev)

{

	blk_queue_dma_alignment(sdev->request_queue, (512 - 1));



	return 0;

}





static void sbp2scsi_slave_destroy(struct scsi_device *sdev)

{

	((struct scsi_id_instance_data *)sdev->host->hostdata[0])->sdev = NULL;

	return;

}





/*

 * Called by scsi stack when something has really gone wrong.  Usually

 * called when a command has timed-out for some reason.
@@ -2705,7 +2730,7 @@ static int sbp2scsi_abort(struct scsi_cmnd *SCpnt) 
	SBP2_ERR("aborting sbp2 command");

	scsi_print_command(SCpnt);



	if (scsi_id) {

	if (sbp2util_node_is_available(scsi_id)) {



		/*

		 * Right now, just return any matching command structures
@@ -2742,31 +2767,24 @@ static int sbp2scsi_abort(struct scsi_cmnd *SCpnt) 
/*

 * Called by scsi stack when something has really gone wrong.

 */

static int __sbp2scsi_reset(struct scsi_cmnd *SCpnt)

static int sbp2scsi_reset(struct scsi_cmnd *SCpnt)

{

	struct scsi_id_instance_data *scsi_id =

		(struct scsi_id_instance_data *)SCpnt->device->host->hostdata[0];

	unsigned long flags;



	SBP2_ERR("reset requested");



	if (scsi_id) {

	spin_lock_irqsave(SCpnt->device->host->host_lock, flags);



	if (sbp2util_node_is_available(scsi_id)) {

		SBP2_ERR("Generating sbp2 fetch agent reset");

		sbp2_agent_reset(scsi_id, 0);

	}



	return(SUCCESS);

}



static int sbp2scsi_reset(struct scsi_cmnd *SCpnt)

{

	unsigned long flags;

	int rc;



	spin_lock_irqsave(SCpnt->device->host->host_lock, flags);

	rc = __sbp2scsi_reset(SCpnt);

	spin_unlock_irqrestore(SCpnt->device->host->host_lock, flags);



	return rc;

	return SUCCESS;

}



static const char *sbp2scsi_info (struct Scsi_Host *host)
@@ -2817,7 +2835,9 @@ static struct scsi_host_template scsi_driver_template = { 
	.eh_device_reset_handler =	sbp2scsi_reset,

	.eh_bus_reset_handler =		sbp2scsi_reset,

	.eh_host_reset_handler =	sbp2scsi_reset,

	.slave_alloc =			sbp2scsi_slave_alloc,

	.slave_configure =		sbp2scsi_slave_configure,

	.slave_destroy =		sbp2scsi_slave_destroy,

	.this_id =			-1,

	.sg_tablesize =			SG_ALL,

	.use_clustering =		ENABLE_CLUSTERING,