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Commit 318ddb34 authored by Wen Xiong's avatar Wen Xiong Committed by Martin K. Petersen
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scsi: ipr: System hung while dlpar adding primary ipr adapter back 



While dlpar adding primary ipr adapter back, driver goes through adapter
initialization then schedule ipr_worker_thread to start te disk scan by
dropping the host lock, calling scsi_add_device.  Then get the adapter reset
request again, so driver does scsi_block_requests, this will cause the
scsi_add_device get hung until we unblock. But we can't run ipr_worker_thread
to do the unblock because its stuck in scsi_add_device.

This patch fixes the issue.

[mkp: typo and whitespace fixes]

Signed-off-by: default avatarWen Xiong <wenxiong@linux.vnet.ibm.com>
Acked-by: default avatarBrian King <brking@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 8c39e269

drivers/scsi/ipr.c

+61 −45
Original line number Diff line number Diff line
@@ -3335,6 +3335,65 @@ static void ipr_release_dump(struct kref *kref) 
	LEAVE;

}



static void ipr_add_remove_thread(struct work_struct *work)

{

	unsigned long lock_flags;

	struct ipr_resource_entry *res;

	struct scsi_device *sdev;

	struct ipr_ioa_cfg *ioa_cfg =

		container_of(work, struct ipr_ioa_cfg, scsi_add_work_q);

	u8 bus, target, lun;

	int did_work;



	ENTER;

	spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);



restart:

	do {

		did_work = 0;

		if (!ioa_cfg->hrrq[IPR_INIT_HRRQ].allow_cmds) {

			spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

			return;

		}



		list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {

			if (res->del_from_ml && res->sdev) {

				did_work = 1;

				sdev = res->sdev;

				if (!scsi_device_get(sdev)) {

					if (!res->add_to_ml)

						list_move_tail(&res->queue, &ioa_cfg->free_res_q);

					else

						res->del_from_ml = 0;

					spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

					scsi_remove_device(sdev);

					scsi_device_put(sdev);

					spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);

				}

				break;

			}

		}

	} while (did_work);



	list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {

		if (res->add_to_ml) {

			bus = res->bus;

			target = res->target;

			lun = res->lun;

			res->add_to_ml = 0;

			spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

			scsi_add_device(ioa_cfg->host, bus, target, lun);

			spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);

			goto restart;

		}

	}



	ioa_cfg->scan_done = 1;

	spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

	kobject_uevent(&ioa_cfg->host->shost_dev.kobj, KOBJ_CHANGE);

	LEAVE;

}



/**

 * ipr_worker_thread - Worker thread

 * @work:		ioa config struct
@@ -3349,13 +3408,9 @@ static void ipr_release_dump(struct kref *kref) 
static void ipr_worker_thread(struct work_struct *work)

{

	unsigned long lock_flags;

	struct ipr_resource_entry *res;

	struct scsi_device *sdev;

	struct ipr_dump *dump;

	struct ipr_ioa_cfg *ioa_cfg =

		container_of(work, struct ipr_ioa_cfg, work_q);

	u8 bus, target, lun;

	int did_work;



	ENTER;

	spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);
@@ -3393,49 +3448,9 @@ static void ipr_worker_thread(struct work_struct *work) 
		return;

	}



restart:

	do {

		did_work = 0;

		if (!ioa_cfg->hrrq[IPR_INIT_HRRQ].allow_cmds) {

			spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

			return;

		}

	schedule_work(&ioa_cfg->scsi_add_work_q);



		list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {

			if (res->del_from_ml && res->sdev) {

				did_work = 1;

				sdev = res->sdev;

				if (!scsi_device_get(sdev)) {

					if (!res->add_to_ml)

						list_move_tail(&res->queue, &ioa_cfg->free_res_q);

					else

						res->del_from_ml = 0;

	spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

					scsi_remove_device(sdev);

					scsi_device_put(sdev);

					spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);

				}

				break;

			}

		}

	} while (did_work);



	list_for_each_entry(res, &ioa_cfg->used_res_q, queue) {

		if (res->add_to_ml) {

			bus = res->bus;

			target = res->target;

			lun = res->lun;

			res->add_to_ml = 0;

			spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

			scsi_add_device(ioa_cfg->host, bus, target, lun);

			spin_lock_irqsave(ioa_cfg->host->host_lock, lock_flags);

			goto restart;

		}

	}



	ioa_cfg->scan_done = 1;

	spin_unlock_irqrestore(ioa_cfg->host->host_lock, lock_flags);

	kobject_uevent(&ioa_cfg->host->shost_dev.kobj, KOBJ_CHANGE);

	LEAVE;

}
@@ -9933,6 +9948,7 @@ static void ipr_init_ioa_cfg(struct ipr_ioa_cfg *ioa_cfg, 
	INIT_LIST_HEAD(&ioa_cfg->free_res_q);

	INIT_LIST_HEAD(&ioa_cfg->used_res_q);

	INIT_WORK(&ioa_cfg->work_q, ipr_worker_thread);

	INIT_WORK(&ioa_cfg->scsi_add_work_q, ipr_add_remove_thread);

	init_waitqueue_head(&ioa_cfg->reset_wait_q);

	init_waitqueue_head(&ioa_cfg->msi_wait_q);

	init_waitqueue_head(&ioa_cfg->eeh_wait_q);

drivers/scsi/ipr.h

+1 −0
Original line number Diff line number Diff line
@@ -1575,6 +1575,7 @@ struct ipr_ioa_cfg { 
	u8 saved_mode_page_len;



	struct work_struct work_q;

	struct work_struct scsi_add_work_q;

	struct workqueue_struct *reset_work_q;



	wait_queue_head_t reset_wait_q;