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Date: Tue, 21 Dec 2010 16:01:57 +0100
From: Tejun Heo <tj@...nel.org>
To: linux-scsi@...r.kernel.org, James.Bottomley@...e.de,
fujita.tomonori@....ntt.co.jp, linux-kernel@...r.kernel.org,
Eric.Moore@....com, dgilbert@...erlog.com
Cc: Tejun Heo <tj@...nel.org>
Subject: [PATCH 2/6] 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: Tejun Heo <tj@...nel.org>
---
drivers/scsi/pm8001/pm8001_hwi.c | 37 +++++++++++++++++--------------------
drivers/scsi/pm8001/pm8001_init.c | 27 ++++++++++++++++++---------
drivers/scsi/pm8001/pm8001_sas.h | 10 ++++++----
3 files changed, 41 insertions(+), 33 deletions(-)
diff --git a/drivers/scsi/pm8001/pm8001_hwi.c b/drivers/scsi/pm8001/pm8001_hwi.c
index d8db013..18b6c55 100644
--- a/drivers/scsi/pm8001/pm8001_hwi.c
+++ b/drivers/scsi/pm8001/pm8001_hwi.c
@@ -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;
+ 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;
diff --git a/drivers/scsi/pm8001/pm8001_init.c b/drivers/scsi/pm8001/pm8001_init.c
index f8c86b2..40cf80d 100644
--- a/drivers/scsi/pm8001/pm8001_init.c
+++ b/drivers/scsi/pm8001/pm8001_init.c
@@ -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);
diff --git a/drivers/scsi/pm8001/pm8001_sas.h b/drivers/scsi/pm8001/pm8001_sas.h
index 7f064f9..bdb6b27 100644
--- a/drivers/scsi/pm8001/pm8001_sas.h
+++ b/drivers/scsi/pm8001/pm8001_sas.h
@@ -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);
--
1.7.1
--
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