From: Rob Evers <revers@redhat.com> Date: Fri, 5 Feb 2010 16:42:55 -0500 Subject: [scsi] scsi_dh: make rdac hw handler's activate() async Message-id: <20100205164223.24469.22694.sendpatchset@localhost.localdomain> Patchwork-id: 23154 O-Subject: [RHEL5.5 PATCH 2/2] scsi_dh: Make rdac hardware handler's activate() async Bugzilla: 537514 RH-Acked-by: Tomas Henzl <thenzl@redhat.com> https://bugzilla.redhat.com/show_bug.cgi?id=537514 From: Chandra Seetharaman <sekharan@us.ibm.com> Date: Wed, 21 Oct 2009 16:22:51 +0000 (-0700) Subject: [SCSI] scsi_dh: Make rdac hardware handler's activate() async X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fjejb%2Fscsi-misc-2.6.git;a=commitdiff_plain;h=87f5f7800a3477b20c2a7760d5a150da572424d3;hp=d1c55de2d73e9cdc7b4839bf3b3dc2ca8c146605 [SCSI] 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@lsi.com> Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de> diff --git a/drivers/scsi/device_handler/scsi_dh_rdac.c b/drivers/scsi/device_handler/scsi_dh_rdac.c index 111a309..7b42a94 100644 --- a/drivers/scsi/device_handler/scsi_dh_rdac.c +++ b/drivers/scsi/device_handler/scsi_dh_rdac.c @@ -24,6 +24,7 @@ #include <scsi/scsi_eh.h> #include <scsi/scsi_cmnd.h> #include <scsi/scsi_dh.h> +#include <linux/workqueue.h> #include "../scsi_priv.h" #define RDAC_NAME "rdac" @@ -141,7 +142,13 @@ struct rdac_controller { } 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 */ @@ -201,8 +208,17 @@ static const char *lun_state[] = "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(void *data); /* * module parameter to enable rdac debug logging. @@ -285,7 +301,6 @@ static struct request *rdac_failover_get(struct scsi_device *sdev, 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; @@ -295,7 +310,6 @@ static struct request *rdac_failover_get(struct scsi_device *sdev, 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; @@ -329,6 +343,7 @@ static void release_controller(struct kref *kref) 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); @@ -367,6 +382,11 @@ static struct rdac_controller *get_controller(u8 *subsys_id, u8 *slot_id, 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, ctlr); + INIT_LIST_HEAD(&ctlr->ms_head); list_add(&ctlr->node, &ctlr_list); done: spin_unlock(&list_lock); @@ -493,7 +513,7 @@ static int set_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h) } 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; @@ -536,11 +556,28 @@ done: return err; } -static int send_mode_select(struct scsi_device *sdev, struct rdac_dh_data *h) +static void send_mode_select(void *data) { + struct rdac_controller *ctlr = data; 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; @@ -548,6 +585,10 @@ retry: 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, @@ -568,7 +609,41 @@ retry: } 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_NOIO); + 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, @@ -581,8 +656,11 @@ static int rdac_activate(struct scsi_device *sdev, 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 +871,26 @@ static int __init rdac_init(void) 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); }