I have tested this patch on LSI rdac storage. It works pretty well.. > -----Original Message----- > From: linux-scsi-owner@xxxxxxxxxxxxxxx [mailto:linux-scsi- > owner@xxxxxxxxxxxxxxx] On Behalf Of Chandra Seetharaman > Sent: Wednesday, October 21, 2009 11:23 AM > To: linux-scsi@xxxxxxxxxxxxxxx > Cc: dm-devel@xxxxxxxxxx; Moger, Babu; michaelc@xxxxxxxxxxx; > Benoit_Arthur@xxxxxxx; Eddie.Williams@xxxxxxxxxxxx; > berthiaume_wayne@xxxxxxx; Chandra Seetharaman > Subject: [PATCH 2/4] scsi_dh: Make rdac hardware handler's activate() > async > > Batch up MODE_SELECT in rdac device handler. > > LSI RDAC storage has the capability of handling mode selects for > multiple luns in a same command. Make use of that ability to send > as few MODE SELECTs as possible to the storage controller as possible. > > This patch creates a work queue and queues up activate requests > when a MODE SELECT is sent down the wire. When that MODE SELECT > completes, it compiles queued up activate requests for multiple > luns into a single MODE SELECT. > > This reduces the time to do failover/failback of large number of LUNS. > > Signed-off-by: Babu Moger <babu.moger@xxxxxxx> > Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx> Tested-by: Babu Moger <babu.moger@xxxxxxx> > > --- > drivers/scsi/device_handler/scsi_dh_rdac.c | 108 > +++++++++++++++++++++++++++-- > 1 file changed, 100 insertions(+), 8 deletions(-) > > Index: linux-2.6.32-rc5/drivers/scsi/device_handler/scsi_dh_rdac.c > =================================================================== > --- linux-2.6.32-rc5.orig/drivers/scsi/device_handler/scsi_dh_rdac.c > 2009-10-20 18:26:14.000000000 -0700 > +++ linux-2.6.32-rc5/drivers/scsi/device_handler/scsi_dh_rdac.c 2009- > 10-20 18:26:29.000000000 -0700 > @@ -22,6 +22,7 @@ > #include <scsi/scsi.h> > #include <scsi/scsi_eh.h> > #include <scsi/scsi_dh.h> > +#include <linux/workqueue.h> > > #define RDAC_NAME "rdac" > #define RDAC_RETRY_COUNT 5 > @@ -138,7 +139,13 @@ > } mode_select; > u8 index; > u8 array_name[ARRAY_LABEL_LEN]; > + spinlock_t ms_lock; > + int ms_queued; > + struct work_struct ms_work; > + struct scsi_device *ms_sdev; > + struct list_head ms_head; > }; > + > struct c8_inquiry { > u8 peripheral_info; > u8 page_code; /* 0xC8 */ > @@ -198,8 +205,17 @@ > "owned (AVT mode)", > }; > > +struct rdac_queue_data { > + struct list_head entry; > + struct rdac_dh_data *h; > + activate_complete callback_fn; > + void *callback_data; > +}; > + > static LIST_HEAD(ctlr_list); > static DEFINE_SPINLOCK(list_lock); > +static struct workqueue_struct *kmpath_rdacd; > +static void send_mode_select(struct work_struct *work); > > /* > * module parameter to enable rdac debug logging. > @@ -281,7 +297,6 @@ > rdac_pg->subpage_code = 0x1; > rdac_pg->page_len[0] = 0x01; > rdac_pg->page_len[1] = 0x28; > - rdac_pg->lun_table[h->lun] = 0x81; > } else { > struct rdac_pg_legacy *rdac_pg; > > @@ -291,7 +306,6 @@ > common = &rdac_pg->common; > rdac_pg->page_code = RDAC_PAGE_CODE_REDUNDANT_CONTROLLER; > rdac_pg->page_len = 0x68; > - rdac_pg->lun_table[h->lun] = 0x81; > } > common->rdac_mode[1] = RDAC_MODE_TRANSFER_SPECIFIED_LUNS; > common->quiescence_timeout = RDAC_QUIESCENCE_TIME; > @@ -325,6 +339,7 @@ > struct rdac_controller *ctlr; > ctlr = container_of(kref, struct rdac_controller, kref); > > + flush_workqueue(kmpath_rdacd); > spin_lock(&list_lock); > list_del(&ctlr->node); > spin_unlock(&list_lock); > @@ -363,6 +378,11 @@ > > kref_init(&ctlr->kref); > ctlr->use_ms10 = -1; > + ctlr->ms_queued = 0; > + ctlr->ms_sdev = NULL; > + spin_lock_init(&ctlr->ms_lock); > + INIT_WORK(&ctlr->ms_work, send_mode_select); > + INIT_LIST_HEAD(&ctlr->ms_head); > list_add(&ctlr->node, &ctlr_list); > done: > spin_unlock(&list_lock); > @@ -490,7 +510,7 @@ > } > > static int mode_select_handle_sense(struct scsi_device *sdev, > - unsigned char *sensebuf) > + unsigned char *sensebuf) > { > struct scsi_sense_hdr sense_hdr; > int err = SCSI_DH_IO, ret; > @@ -533,11 +553,29 @@ > return err; > } > > -static int send_mode_select(struct scsi_device *sdev, struct > rdac_dh_data *h) > +static void send_mode_select(struct work_struct *work) > { > + struct rdac_controller *ctlr = > + container_of(work, struct rdac_controller, ms_work); > struct request *rq; > + struct scsi_device *sdev = ctlr->ms_sdev; > + struct rdac_dh_data *h = get_rdac_data(sdev); > struct request_queue *q = sdev->request_queue; > int err, retry_cnt = RDAC_RETRY_COUNT; > + struct rdac_queue_data *tmp, *qdata; > + LIST_HEAD(list); > + u8 *lun_table; > + > + spin_lock(&ctlr->ms_lock); > + list_splice_init(&ctlr->ms_head, &list); > + ctlr->ms_queued = 0; > + ctlr->ms_sdev = NULL; > + spin_unlock(&ctlr->ms_lock); > + > + if (ctlr->use_ms10) > + lun_table = ctlr->mode_select.expanded.lun_table; > + else > + lun_table = ctlr->mode_select.legacy.lun_table; > > retry: > err = SCSI_DH_RES_TEMP_UNAVAIL; > @@ -545,6 +583,10 @@ > if (!rq) > goto done; > > + list_for_each_entry(qdata, &list, entry) { > + lun_table[qdata->h->lun] = 0x81; > + } > + > RDAC_LOG(RDAC_LOG_FAILOVER, sdev, "array %s, ctlr %d, " > "%s MODE_SELECT command", > (char *) h->ctlr->array_name, h->ctlr->index, > @@ -565,7 +607,41 @@ > } > > done: > - return err; > + list_for_each_entry_safe(qdata, tmp, &list, entry) { > + list_del(&qdata->entry); > + if (err == SCSI_DH_OK) > + qdata->h->state = RDAC_STATE_ACTIVE; > + if (qdata->callback_fn) > + qdata->callback_fn(qdata->callback_data, err); > + kfree(qdata); > + } > + return; > +} > + > +static int queue_mode_select(struct scsi_device *sdev, > + activate_complete fn, void *data) > +{ > + struct rdac_queue_data *qdata; > + struct rdac_controller *ctlr; > + > + qdata = kzalloc(sizeof(*qdata), GFP_KERNEL); > + if (!qdata) > + return SCSI_DH_RETRY; > + > + qdata->h = get_rdac_data(sdev); > + qdata->callback_fn = fn; > + qdata->callback_data = data; > + > + ctlr = qdata->h->ctlr; > + spin_lock(&ctlr->ms_lock); > + list_add_tail(&qdata->entry, &ctlr->ms_head); > + if (!ctlr->ms_queued) { > + ctlr->ms_queued = 1; > + ctlr->ms_sdev = sdev; > + queue_work(kmpath_rdacd, &ctlr->ms_work); > + } > + spin_unlock(&ctlr->ms_lock); > + return SCSI_DH_OK; > } > > static int rdac_activate(struct scsi_device *sdev, > @@ -578,8 +654,11 @@ > if (err != SCSI_DH_OK) > goto done; > > - if (h->lun_state == RDAC_LUN_UNOWNED) > - err = send_mode_select(sdev, h); > + if (h->lun_state == RDAC_LUN_UNOWNED) { > + err = queue_mode_select(sdev, fn, data); > + if (err == SCSI_DH_OK) > + return 0; > + } > done: > if (fn) > fn(data, err); > @@ -793,13 +872,26 @@ > int r; > > r = scsi_register_device_handler(&rdac_dh); > - if (r != 0) > + if (r != 0) { > printk(KERN_ERR "Failed to register scsi device handler."); > + goto done; > + } > + > + /* > + * Create workqueue to handle mode selects for rdac > + */ > + kmpath_rdacd = create_singlethread_workqueue("kmpath_rdacd"); > + if (!kmpath_rdacd) { > + scsi_unregister_device_handler(&rdac_dh); > + printk(KERN_ERR "kmpath_rdacd creation failed.\n"); > + } > +done: > return r; > } > > static void __exit rdac_exit(void) > { > + destroy_workqueue(kmpath_rdacd); > scsi_unregister_device_handler(&rdac_dh); > } > > -- > To unsubscribe from this list: send the line "unsubscribe linux-scsi" > in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
