Commit 429305e4 authored by Tejun Heo's avatar Tejun Heo Committed by James Bottomley
Browse files

[SCSI] pm8001: simplify workqueue usage 



pm8001 manages its own list of pending works and cancel them on device
free.  It is unnecessarily complex and has a race condition - the
works are canceled but not synced, so the work could still be running
during and after the data structures are freed.

This patch simplifies workqueue usage.

* A driver specific workqueue pm8001_wq is created to serve these
  work items.

* To avoid confusion, the "queue" suffixes are dropped from work items
  and functions.

* Delayed queueing was never used.  pm8001_work now uses work_struct
  instead.

* The driver no longer keeps track of pending works.  All pm8001_works
  are queued to pm8001_wq and the workqueue is flushed as necessary.

flush_scheduled_work() usage is removed during conversion.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarJack Wang <jack_wang@usish.com>
Signed-off-by: default avatarJames Bottomley <James.Bottomley@suse.de>
parent a684b8da

drivers/scsi/pm8001/pm8001_hwi.c

+17 −20
Original line number Diff line number Diff line
@@ -1382,53 +1382,50 @@ static u32 mpi_msg_consume(struct pm8001_hba_info *pm8001_ha, 
	return MPI_IO_STATUS_BUSY;

}



static void pm8001_work_queue(struct work_struct *work)

static void pm8001_work_fn(struct work_struct *work)

{

	struct delayed_work *dw = container_of(work, struct delayed_work, work);

	struct pm8001_wq *wq = container_of(dw, struct pm8001_wq, work_q);

	struct pm8001_work *pw = container_of(work, struct pm8001_work, work);

	struct pm8001_device *pm8001_dev;

	struct domain_device *dev;



	switch (wq->handler) {

	switch (pw->handler) {

	case IO_OPEN_CNX_ERROR_IT_NEXUS_LOSS:

		pm8001_dev = wq->data;

		pm8001_dev = pw->data;

		dev = pm8001_dev->sas_device;

		pm8001_I_T_nexus_reset(dev);

		break;

	case IO_OPEN_CNX_ERROR_STP_RESOURCES_BUSY:

		pm8001_dev = wq->data;

		pm8001_dev = pw->data;

		dev = pm8001_dev->sas_device;

		pm8001_I_T_nexus_reset(dev);

		break;

	case IO_DS_IN_ERROR:

		pm8001_dev = wq->data;

		pm8001_dev = pw->data;

		dev = pm8001_dev->sas_device;

		pm8001_I_T_nexus_reset(dev);

		break;

	case IO_DS_NON_OPERATIONAL:

		pm8001_dev = wq->data;

		pm8001_dev = pw->data;

		dev = pm8001_dev->sas_device;

		pm8001_I_T_nexus_reset(dev);

		break;

	}

	list_del(&wq->entry);

	kfree(wq);

	kfree(pw);

}



static int pm8001_handle_event(struct pm8001_hba_info *pm8001_ha, void *data,

			       int handler)

{

	struct pm8001_wq *wq;

	struct pm8001_work *pw;

	int ret = 0;



	wq = kmalloc(sizeof(struct pm8001_wq), GFP_ATOMIC);

	if (wq) {

		wq->pm8001_ha = pm8001_ha;

		wq->data = data;

		wq->handler = handler;

		INIT_DELAYED_WORK(&wq->work_q, pm8001_work_queue);

		list_add_tail(&wq->entry, &pm8001_ha->wq_list);

		schedule_delayed_work(&wq->work_q, 0);

	pw = kmalloc(sizeof(struct pm8001_work), GFP_ATOMIC);

	if (pw) {

		pw->pm8001_ha = pm8001_ha;

		pw->data = data;

		pw->handler = handler;

		INIT_WORK(&pw->work, pm8001_work_fn);

		queue_work(pm8001_wq, &pw->work);

	} else

		ret = -ENOMEM;

drivers/scsi/pm8001/pm8001_init.c

+18 −9
Original line number Diff line number Diff line
@@ -51,6 +51,8 @@ static int pm8001_id; 


LIST_HEAD(hba_list);



struct workqueue_struct *pm8001_wq;



/**

 * The main structure which LLDD must register for scsi core.

 */
@@ -134,7 +136,6 @@ static void __devinit pm8001_phy_init(struct pm8001_hba_info *pm8001_ha, 
static void pm8001_free(struct pm8001_hba_info *pm8001_ha)

{

	int i;

	struct pm8001_wq *wq;



	if (!pm8001_ha)

		return;
@@ -150,8 +151,7 @@ static void pm8001_free(struct pm8001_hba_info *pm8001_ha) 
	PM8001_CHIP_DISP->chip_iounmap(pm8001_ha);

	if (pm8001_ha->shost)

		scsi_host_put(pm8001_ha->shost);

	list_for_each_entry(wq, &pm8001_ha->wq_list, entry)

		cancel_delayed_work(&wq->work_q);

	flush_workqueue(pm8001_wq);

	kfree(pm8001_ha->tags);

	kfree(pm8001_ha);

}
@@ -381,7 +381,6 @@ pm8001_pci_alloc(struct pci_dev *pdev, u32 chip_id, struct Scsi_Host *shost) 
	pm8001_ha->sas = sha;

	pm8001_ha->shost = shost;

	pm8001_ha->id = pm8001_id++;

	INIT_LIST_HEAD(&pm8001_ha->wq_list);

	pm8001_ha->logging_level = 0x01;

	sprintf(pm8001_ha->name, "%s%d", DRV_NAME, pm8001_ha->id);

#ifdef PM8001_USE_TASKLET
@@ -758,7 +757,7 @@ static int pm8001_pci_suspend(struct pci_dev *pdev, pm_message_t state) 
	int i , pos;

	u32 device_state;

	pm8001_ha = sha->lldd_ha;

	flush_scheduled_work();

	flush_workqueue(pm8001_wq);

	scsi_block_requests(pm8001_ha->shost);

	pos = pci_find_capability(pdev, PCI_CAP_ID_PM);

	if (pos == 0) {
@@ -870,17 +869,26 @@ static struct pci_driver pm8001_pci_driver = { 
 */

static int __init pm8001_init(void)

{

	int rc;

	int rc = -ENOMEM;



	pm8001_wq = alloc_workqueue("pm8001", 0, 0);

	if (!pm8001_wq)

		goto err;



	pm8001_id = 0;

	pm8001_stt = sas_domain_attach_transport(&pm8001_transport_ops);

	if (!pm8001_stt)

		return -ENOMEM;

		goto err_wq;

	rc = pci_register_driver(&pm8001_pci_driver);

	if (rc)

		goto err_out;

		goto err_tp;

	return 0;

err_out:



err_tp:

	sas_release_transport(pm8001_stt);

err_wq:

	destroy_workqueue(pm8001_wq);

err:

	return rc;

}
@@ -888,6 +896,7 @@ static void __exit pm8001_exit(void) 
{

	pci_unregister_driver(&pm8001_pci_driver);

	sas_release_transport(pm8001_stt);

	destroy_workqueue(pm8001_wq);

}



module_init(pm8001_init);

drivers/scsi/pm8001/pm8001_sas.h

+6 −4
Original line number Diff line number Diff line
@@ -50,6 +50,7 @@ 
#include <linux/dma-mapping.h>

#include <linux/pci.h>

#include <linux/interrupt.h>

#include <linux/workqueue.h>

#include <scsi/libsas.h>

#include <scsi/scsi_tcq.h>

#include <scsi/sas_ata.h>
@@ -379,18 +380,16 @@ struct pm8001_hba_info { 
#ifdef PM8001_USE_TASKLET

	struct tasklet_struct	tasklet;

#endif

	struct list_head 	wq_list;

	u32			logging_level;

	u32			fw_status;

	const struct firmware 	*fw_image;

};



struct pm8001_wq {

	struct delayed_work work_q;

struct pm8001_work {

	struct work_struct work;

	struct pm8001_hba_info *pm8001_ha;

	void *data;

	int handler;

	struct list_head entry;

};



struct pm8001_fw_image_header {
@@ -460,6 +459,9 @@ struct fw_control_ex { 
	void			*param3;

};



/* pm8001 workqueue */

extern struct workqueue_struct *pm8001_wq;



/******************** function prototype *********************/

int pm8001_tag_alloc(struct pm8001_hba_info *pm8001_ha, u32 *tag_out);

void pm8001_tag_init(struct pm8001_hba_info *pm8001_ha);

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