On Mon, 2011-01-24 at 14:57 +0100, Tejun Heo wrote:
> 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.
cc'ing pm8001 maintainers for an opinion. Jack could you look at this
and ack, please.
Thanks,
James
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> ---
> 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 b95285f..002360d 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);
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