4 * Module interface and handling of zfcp data structures.
6 * Copyright IBM Corporation 2002, 2008
11 * Martin Peschke (originator of the driver)
16 * Heiko Carstens (kernel 2.6 port of the driver)
28 #include <linux/miscdevice.h>
33 MODULE_AUTHOR("IBM Deutschland Entwicklung GmbH - linux390@de.ibm.com");
34 MODULE_DESCRIPTION("FCP HBA driver");
35 MODULE_LICENSE("GPL");
37 module_param(device, charp, 0400);
38 MODULE_PARM_DESC(device, "specify initial device");
40 static int zfcp_reqlist_alloc(struct zfcp_adapter *adapter)
44 adapter->req_list = kcalloc(REQUEST_LIST_SIZE, sizeof(struct list_head),
46 if (!adapter->req_list)
49 for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
50 INIT_LIST_HEAD(&adapter->req_list[idx]);
55 * zfcp_reqlist_isempty - is the request list empty
56 * @adapter: pointer to struct zfcp_adapter
58 * Returns: true if list is empty, false otherwise
60 int zfcp_reqlist_isempty(struct zfcp_adapter *adapter)
64 for (idx = 0; idx < REQUEST_LIST_SIZE; idx++)
65 if (!list_empty(&adapter->req_list[idx]))
70 static int __init zfcp_device_setup(char *devstr)
78 /* duplicate devstr and keep the original for sysfs presentation*/
79 str = kmalloc(strlen(devstr) + 1, GFP_KERNEL);
85 token = strsep(&str, ",");
86 if (!token || strlen(token) >= BUS_ID_SIZE)
88 strncpy(zfcp_data.init_busid, token, BUS_ID_SIZE);
90 token = strsep(&str, ",");
91 if (!token || strict_strtoull(token, 0, &zfcp_data.init_wwpn))
94 token = strsep(&str, ",");
95 if (!token || strict_strtoull(token, 0, &zfcp_data.init_fcp_lun))
103 pr_err("zfcp: Parse error for device parameter string %s, "
104 "device not attached.\n", devstr);
108 static struct zfcp_adapter *zfcp_get_adapter_by_busid(char *bus_id)
110 struct zfcp_adapter *adapter;
112 list_for_each_entry(adapter, &zfcp_data.adapter_list_head, list)
113 if ((strncmp(bus_id, adapter->ccw_device->dev.bus_id,
114 BUS_ID_SIZE) == 0) &&
115 !(atomic_read(&adapter->status) &
116 ZFCP_STATUS_COMMON_REMOVE))
121 static void __init zfcp_init_device_configure(void)
123 struct zfcp_adapter *adapter;
124 struct zfcp_port *port;
125 struct zfcp_unit *unit;
127 down(&zfcp_data.config_sema);
128 read_lock_irq(&zfcp_data.config_lock);
129 adapter = zfcp_get_adapter_by_busid(zfcp_data.init_busid);
131 zfcp_adapter_get(adapter);
132 read_unlock_irq(&zfcp_data.config_lock);
136 port = zfcp_port_enqueue(adapter, zfcp_data.init_wwpn, 0, 0);
139 unit = zfcp_unit_enqueue(port, zfcp_data.init_fcp_lun);
142 up(&zfcp_data.config_sema);
143 ccw_device_set_online(adapter->ccw_device);
144 zfcp_erp_wait(adapter);
145 down(&zfcp_data.config_sema);
150 zfcp_adapter_put(adapter);
152 up(&zfcp_data.config_sema);
156 static struct kmem_cache *zfcp_cache_create(int size, char *name)
159 while ((size - align) > 0)
161 return kmem_cache_create(name , size, align, 0, NULL);
164 static int __init zfcp_module_init(void)
166 int retval = -ENOMEM;
168 zfcp_data.fsf_req_qtcb_cache = zfcp_cache_create(
169 sizeof(struct zfcp_fsf_req_qtcb), "zfcp_fsf");
170 if (!zfcp_data.fsf_req_qtcb_cache)
173 zfcp_data.sr_buffer_cache = zfcp_cache_create(
174 sizeof(struct fsf_status_read_buffer), "zfcp_sr");
175 if (!zfcp_data.sr_buffer_cache)
178 zfcp_data.gid_pn_cache = zfcp_cache_create(
179 sizeof(struct zfcp_gid_pn_data), "zfcp_gid");
180 if (!zfcp_data.gid_pn_cache)
183 INIT_LIST_HEAD(&zfcp_data.adapter_list_head);
184 INIT_LIST_HEAD(&zfcp_data.adapter_remove_lh);
186 sema_init(&zfcp_data.config_sema, 1);
187 rwlock_init(&zfcp_data.config_lock);
189 zfcp_data.scsi_transport_template =
190 fc_attach_transport(&zfcp_transport_functions);
191 if (!zfcp_data.scsi_transport_template)
194 retval = misc_register(&zfcp_cfdc_misc);
196 pr_err("zfcp: registration of misc device zfcp_cfdc failed\n");
200 retval = zfcp_ccw_register();
202 pr_err("zfcp: Registration with common I/O layer failed.\n");
203 goto out_ccw_register;
206 if (zfcp_device_setup(device))
207 zfcp_init_device_configure();
212 misc_deregister(&zfcp_cfdc_misc);
214 fc_release_transport(zfcp_data.scsi_transport_template);
216 kmem_cache_destroy(zfcp_data.gid_pn_cache);
218 kmem_cache_destroy(zfcp_data.sr_buffer_cache);
220 kmem_cache_destroy(zfcp_data.fsf_req_qtcb_cache);
225 module_init(zfcp_module_init);
228 * zfcp_get_unit_by_lun - find unit in unit list of port by FCP LUN
229 * @port: pointer to port to search for unit
230 * @fcp_lun: FCP LUN to search for
232 * Returns: pointer to zfcp_unit or NULL
234 struct zfcp_unit *zfcp_get_unit_by_lun(struct zfcp_port *port,
237 struct zfcp_unit *unit;
239 list_for_each_entry(unit, &port->unit_list_head, list)
240 if ((unit->fcp_lun == fcp_lun) &&
241 !(atomic_read(&unit->status) & ZFCP_STATUS_COMMON_REMOVE))
247 * zfcp_get_port_by_wwpn - find port in port list of adapter by wwpn
248 * @adapter: pointer to adapter to search for port
249 * @wwpn: wwpn to search for
251 * Returns: pointer to zfcp_port or NULL
253 struct zfcp_port *zfcp_get_port_by_wwpn(struct zfcp_adapter *adapter,
256 struct zfcp_port *port;
258 list_for_each_entry(port, &adapter->port_list_head, list)
259 if ((port->wwpn == wwpn) && !(atomic_read(&port->status) &
260 (ZFCP_STATUS_PORT_NO_WWPN | ZFCP_STATUS_COMMON_REMOVE)))
265 static void zfcp_sysfs_unit_release(struct device *dev)
267 kfree(container_of(dev, struct zfcp_unit, sysfs_device));
271 * zfcp_unit_enqueue - enqueue unit to unit list of a port.
272 * @port: pointer to port where unit is added
273 * @fcp_lun: FCP LUN of unit to be enqueued
274 * Returns: pointer to enqueued unit on success, ERR_PTR on error
275 * Locks: config_sema must be held to serialize changes to the unit list
277 * Sets up some unit internal structures and creates sysfs entry.
279 struct zfcp_unit *zfcp_unit_enqueue(struct zfcp_port *port, fcp_lun_t fcp_lun)
281 struct zfcp_unit *unit;
283 unit = kzalloc(sizeof(struct zfcp_unit), GFP_KERNEL);
285 return ERR_PTR(-ENOMEM);
287 atomic_set(&unit->refcount, 0);
288 init_waitqueue_head(&unit->remove_wq);
291 unit->fcp_lun = fcp_lun;
293 snprintf(unit->sysfs_device.bus_id, BUS_ID_SIZE, "0x%016llx", fcp_lun);
294 unit->sysfs_device.parent = &port->sysfs_device;
295 unit->sysfs_device.release = zfcp_sysfs_unit_release;
296 dev_set_drvdata(&unit->sysfs_device, unit);
298 /* mark unit unusable as long as sysfs registration is not complete */
299 atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
301 spin_lock_init(&unit->latencies.lock);
302 unit->latencies.write.channel.min = 0xFFFFFFFF;
303 unit->latencies.write.fabric.min = 0xFFFFFFFF;
304 unit->latencies.read.channel.min = 0xFFFFFFFF;
305 unit->latencies.read.fabric.min = 0xFFFFFFFF;
306 unit->latencies.cmd.channel.min = 0xFFFFFFFF;
307 unit->latencies.cmd.fabric.min = 0xFFFFFFFF;
309 read_lock_irq(&zfcp_data.config_lock);
310 if (zfcp_get_unit_by_lun(port, fcp_lun)) {
311 read_unlock_irq(&zfcp_data.config_lock);
314 read_unlock_irq(&zfcp_data.config_lock);
316 if (device_register(&unit->sysfs_device))
319 if (sysfs_create_group(&unit->sysfs_device.kobj,
320 &zfcp_sysfs_unit_attrs)) {
321 device_unregister(&unit->sysfs_device);
322 return ERR_PTR(-EIO);
326 unit->scsi_lun = scsilun_to_int((struct scsi_lun *)&unit->fcp_lun);
328 write_lock_irq(&zfcp_data.config_lock);
329 list_add_tail(&unit->list, &port->unit_list_head);
330 atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &unit->status);
331 atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &unit->status);
333 write_unlock_irq(&zfcp_data.config_lock);
342 return ERR_PTR(-EINVAL);
346 * zfcp_unit_dequeue - dequeue unit
347 * @unit: pointer to zfcp_unit
349 * waits until all work is done on unit and removes it then from the unit->list
350 * of the associated port.
352 void zfcp_unit_dequeue(struct zfcp_unit *unit)
354 zfcp_unit_wait(unit);
355 write_lock_irq(&zfcp_data.config_lock);
356 list_del(&unit->list);
357 write_unlock_irq(&zfcp_data.config_lock);
359 zfcp_port_put(unit->port);
360 sysfs_remove_group(&unit->sysfs_device.kobj, &zfcp_sysfs_unit_attrs);
361 device_unregister(&unit->sysfs_device);
364 static int zfcp_allocate_low_mem_buffers(struct zfcp_adapter *adapter)
366 /* must only be called with zfcp_data.config_sema taken */
367 adapter->pool.fsf_req_erp =
368 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
369 if (!adapter->pool.fsf_req_erp)
372 adapter->pool.fsf_req_scsi =
373 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
374 if (!adapter->pool.fsf_req_scsi)
377 adapter->pool.fsf_req_abort =
378 mempool_create_slab_pool(1, zfcp_data.fsf_req_qtcb_cache);
379 if (!adapter->pool.fsf_req_abort)
382 adapter->pool.fsf_req_status_read =
383 mempool_create_kmalloc_pool(FSF_STATUS_READS_RECOM,
384 sizeof(struct zfcp_fsf_req));
385 if (!adapter->pool.fsf_req_status_read)
388 adapter->pool.data_status_read =
389 mempool_create_slab_pool(FSF_STATUS_READS_RECOM,
390 zfcp_data.sr_buffer_cache);
391 if (!adapter->pool.data_status_read)
394 adapter->pool.data_gid_pn =
395 mempool_create_slab_pool(1, zfcp_data.gid_pn_cache);
396 if (!adapter->pool.data_gid_pn)
402 static void zfcp_free_low_mem_buffers(struct zfcp_adapter *adapter)
404 /* zfcp_data.config_sema must be held */
405 if (adapter->pool.fsf_req_erp)
406 mempool_destroy(adapter->pool.fsf_req_erp);
407 if (adapter->pool.fsf_req_scsi)
408 mempool_destroy(adapter->pool.fsf_req_scsi);
409 if (adapter->pool.fsf_req_abort)
410 mempool_destroy(adapter->pool.fsf_req_abort);
411 if (adapter->pool.fsf_req_status_read)
412 mempool_destroy(adapter->pool.fsf_req_status_read);
413 if (adapter->pool.data_status_read)
414 mempool_destroy(adapter->pool.data_status_read);
415 if (adapter->pool.data_gid_pn)
416 mempool_destroy(adapter->pool.data_gid_pn);
419 static void zfcp_dummy_release(struct device *dev)
425 * zfcp_status_read_refill - refill the long running status_read_requests
426 * @adapter: ptr to struct zfcp_adapter for which the buffers should be refilled
428 * Returns: 0 on success, 1 otherwise
430 * if there are 16 or more status_read requests missing an adapter_reopen
433 int zfcp_status_read_refill(struct zfcp_adapter *adapter)
435 while (atomic_read(&adapter->stat_miss) > 0)
436 if (zfcp_fsf_status_read(adapter)) {
437 if (atomic_read(&adapter->stat_miss) >= 16) {
438 zfcp_erp_adapter_reopen(adapter, 0, 103, NULL);
443 atomic_dec(&adapter->stat_miss);
447 static void _zfcp_status_read_scheduler(struct work_struct *work)
449 zfcp_status_read_refill(container_of(work, struct zfcp_adapter,
453 static int zfcp_nameserver_enqueue(struct zfcp_adapter *adapter)
455 struct zfcp_port *port;
457 port = zfcp_port_enqueue(adapter, 0, ZFCP_STATUS_PORT_WKA,
458 ZFCP_DID_DIRECTORY_SERVICE);
460 return PTR_ERR(port);
467 * zfcp_adapter_enqueue - enqueue a new adapter to the list
468 * @ccw_device: pointer to the struct cc_device
470 * Returns: 0 if a new adapter was successfully enqueued
471 * -ENOMEM if alloc failed
472 * Enqueues an adapter at the end of the adapter list in the driver data.
473 * All adapter internal structures are set up.
474 * Proc-fs entries are also created.
475 * locks: config_sema must be held to serialise changes to the adapter list
477 int zfcp_adapter_enqueue(struct ccw_device *ccw_device)
479 struct zfcp_adapter *adapter;
482 * Note: It is safe to release the list_lock, as any list changes
483 * are protected by the config_sema, which must be held to get here
486 adapter = kzalloc(sizeof(struct zfcp_adapter), GFP_KERNEL);
490 ccw_device->handler = NULL;
491 adapter->ccw_device = ccw_device;
492 atomic_set(&adapter->refcount, 0);
494 if (zfcp_qdio_allocate(adapter))
495 goto qdio_allocate_failed;
497 if (zfcp_allocate_low_mem_buffers(adapter))
498 goto failed_low_mem_buffers;
500 if (zfcp_reqlist_alloc(adapter))
501 goto failed_low_mem_buffers;
503 if (zfcp_adapter_debug_register(adapter))
504 goto debug_register_failed;
506 init_waitqueue_head(&adapter->remove_wq);
507 init_waitqueue_head(&adapter->erp_thread_wqh);
508 init_waitqueue_head(&adapter->erp_done_wqh);
510 INIT_LIST_HEAD(&adapter->port_list_head);
511 INIT_LIST_HEAD(&adapter->port_remove_lh);
512 INIT_LIST_HEAD(&adapter->erp_ready_head);
513 INIT_LIST_HEAD(&adapter->erp_running_head);
515 spin_lock_init(&adapter->req_list_lock);
517 spin_lock_init(&adapter->hba_dbf_lock);
518 spin_lock_init(&adapter->san_dbf_lock);
519 spin_lock_init(&adapter->scsi_dbf_lock);
520 spin_lock_init(&adapter->rec_dbf_lock);
521 spin_lock_init(&adapter->req_q.lock);
523 rwlock_init(&adapter->erp_lock);
524 rwlock_init(&adapter->abort_lock);
526 sema_init(&adapter->erp_ready_sem, 0);
528 INIT_WORK(&adapter->stat_work, _zfcp_status_read_scheduler);
529 INIT_WORK(&adapter->scan_work, _zfcp_scan_ports_later);
531 /* mark adapter unusable as long as sysfs registration is not complete */
532 atomic_set_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
534 dev_set_drvdata(&ccw_device->dev, adapter);
536 if (sysfs_create_group(&ccw_device->dev.kobj,
537 &zfcp_sysfs_adapter_attrs))
540 adapter->generic_services.parent = &adapter->ccw_device->dev;
541 adapter->generic_services.release = zfcp_dummy_release;
542 snprintf(adapter->generic_services.bus_id, BUS_ID_SIZE,
545 if (device_register(&adapter->generic_services))
546 goto generic_services_failed;
548 write_lock_irq(&zfcp_data.config_lock);
549 atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &adapter->status);
550 list_add_tail(&adapter->list, &zfcp_data.adapter_list_head);
551 write_unlock_irq(&zfcp_data.config_lock);
553 zfcp_data.adapters++;
555 zfcp_nameserver_enqueue(adapter);
559 generic_services_failed:
560 sysfs_remove_group(&ccw_device->dev.kobj,
561 &zfcp_sysfs_adapter_attrs);
563 zfcp_adapter_debug_unregister(adapter);
564 debug_register_failed:
565 dev_set_drvdata(&ccw_device->dev, NULL);
566 kfree(adapter->req_list);
567 failed_low_mem_buffers:
568 zfcp_free_low_mem_buffers(adapter);
569 qdio_allocate_failed:
570 zfcp_qdio_free(adapter);
576 * zfcp_adapter_dequeue - remove the adapter from the resource list
577 * @adapter: pointer to struct zfcp_adapter which should be removed
578 * locks: adapter list write lock is assumed to be held by caller
580 void zfcp_adapter_dequeue(struct zfcp_adapter *adapter)
585 cancel_work_sync(&adapter->scan_work);
586 cancel_work_sync(&adapter->stat_work);
587 zfcp_adapter_scsi_unregister(adapter);
588 device_unregister(&adapter->generic_services);
589 sysfs_remove_group(&adapter->ccw_device->dev.kobj,
590 &zfcp_sysfs_adapter_attrs);
591 dev_set_drvdata(&adapter->ccw_device->dev, NULL);
592 /* sanity check: no pending FSF requests */
593 spin_lock_irqsave(&adapter->req_list_lock, flags);
594 retval = zfcp_reqlist_isempty(adapter);
595 spin_unlock_irqrestore(&adapter->req_list_lock, flags);
599 zfcp_adapter_debug_unregister(adapter);
601 /* remove specified adapter data structure from list */
602 write_lock_irq(&zfcp_data.config_lock);
603 list_del(&adapter->list);
604 write_unlock_irq(&zfcp_data.config_lock);
606 /* decrease number of adapters in list */
607 zfcp_data.adapters--;
609 zfcp_qdio_free(adapter);
611 zfcp_free_low_mem_buffers(adapter);
612 kfree(adapter->req_list);
613 kfree(adapter->fc_stats);
614 kfree(adapter->stats_reset_data);
618 static void zfcp_sysfs_port_release(struct device *dev)
620 kfree(container_of(dev, struct zfcp_port, sysfs_device));
624 * zfcp_port_enqueue - enqueue port to port list of adapter
625 * @adapter: adapter where remote port is added
626 * @wwpn: WWPN of the remote port to be enqueued
627 * @status: initial status for the port
628 * @d_id: destination id of the remote port to be enqueued
629 * Returns: pointer to enqueued port on success, ERR_PTR on error
630 * Locks: config_sema must be held to serialize changes to the port list
632 * All port internal structures are set up and the sysfs entry is generated.
633 * d_id is used to enqueue ports with a well known address like the Directory
634 * Service for nameserver lookup.
636 struct zfcp_port *zfcp_port_enqueue(struct zfcp_adapter *adapter, wwn_t wwpn,
637 u32 status, u32 d_id)
639 struct zfcp_port *port;
643 port = kzalloc(sizeof(struct zfcp_port), GFP_KERNEL);
645 return ERR_PTR(-ENOMEM);
647 init_waitqueue_head(&port->remove_wq);
649 INIT_LIST_HEAD(&port->unit_list_head);
650 INIT_LIST_HEAD(&port->unit_remove_lh);
652 port->adapter = adapter;
656 /* mark port unusable as long as sysfs registration is not complete */
657 atomic_set_mask(status | ZFCP_STATUS_COMMON_REMOVE, &port->status);
658 atomic_set(&port->refcount, 0);
660 if (status & ZFCP_STATUS_PORT_WKA) {
662 case ZFCP_DID_DIRECTORY_SERVICE:
663 bus_id = "directory";
665 case ZFCP_DID_MANAGEMENT_SERVICE:
666 bus_id = "management";
668 case ZFCP_DID_KEY_DISTRIBUTION_SERVICE:
669 bus_id = "key_distribution";
671 case ZFCP_DID_ALIAS_SERVICE:
674 case ZFCP_DID_TIME_SERVICE:
679 return ERR_PTR(-EINVAL);
681 snprintf(port->sysfs_device.bus_id, BUS_ID_SIZE, "%s", bus_id);
682 port->sysfs_device.parent = &adapter->generic_services;
684 snprintf(port->sysfs_device.bus_id,
685 BUS_ID_SIZE, "0x%016llx", wwpn);
686 port->sysfs_device.parent = &adapter->ccw_device->dev;
689 port->sysfs_device.release = zfcp_sysfs_port_release;
690 dev_set_drvdata(&port->sysfs_device, port);
692 read_lock_irq(&zfcp_data.config_lock);
693 if (!(status & ZFCP_STATUS_PORT_NO_WWPN))
694 if (zfcp_get_port_by_wwpn(adapter, wwpn)) {
695 read_unlock_irq(&zfcp_data.config_lock);
698 read_unlock_irq(&zfcp_data.config_lock);
700 if (device_register(&port->sysfs_device))
703 if (status & ZFCP_STATUS_PORT_WKA)
704 retval = sysfs_create_group(&port->sysfs_device.kobj,
705 &zfcp_sysfs_ns_port_attrs);
707 retval = sysfs_create_group(&port->sysfs_device.kobj,
708 &zfcp_sysfs_port_attrs);
711 device_unregister(&port->sysfs_device);
717 write_lock_irq(&zfcp_data.config_lock);
718 list_add_tail(&port->list, &adapter->port_list_head);
719 atomic_clear_mask(ZFCP_STATUS_COMMON_REMOVE, &port->status);
720 atomic_set_mask(ZFCP_STATUS_COMMON_RUNNING, &port->status);
721 if (d_id == ZFCP_DID_DIRECTORY_SERVICE)
722 if (!adapter->nameserver_port)
723 adapter->nameserver_port = port;
726 write_unlock_irq(&zfcp_data.config_lock);
728 zfcp_adapter_get(adapter);
734 return ERR_PTR(-EINVAL);
738 * zfcp_port_dequeue - dequeues a port from the port list of the adapter
739 * @port: pointer to struct zfcp_port which should be removed
741 void zfcp_port_dequeue(struct zfcp_port *port)
743 zfcp_port_wait(port);
744 write_lock_irq(&zfcp_data.config_lock);
745 list_del(&port->list);
746 port->adapter->ports--;
747 write_unlock_irq(&zfcp_data.config_lock);
749 fc_remote_port_delete(port->rport);
751 zfcp_adapter_put(port->adapter);
752 if (atomic_read(&port->status) & ZFCP_STATUS_PORT_WKA)
753 sysfs_remove_group(&port->sysfs_device.kobj,
754 &zfcp_sysfs_ns_port_attrs);
756 sysfs_remove_group(&port->sysfs_device.kobj,
757 &zfcp_sysfs_port_attrs);
758 device_unregister(&port->sysfs_device);
762 * zfcp_sg_free_table - free memory used by scatterlists
763 * @sg: pointer to scatterlist
764 * @count: number of scatterlist which are to be free'ed
765 * the scatterlist are expected to reference pages always
767 void zfcp_sg_free_table(struct scatterlist *sg, int count)
771 for (i = 0; i < count; i++, sg++)
773 free_page((unsigned long) sg_virt(sg));
779 * zfcp_sg_setup_table - init scatterlist and allocate, assign buffers
780 * @sg: pointer to struct scatterlist
781 * @count: number of scatterlists which should be assigned with buffers
784 * Returns: 0 on success, -ENOMEM otherwise
786 int zfcp_sg_setup_table(struct scatterlist *sg, int count)
791 sg_init_table(sg, count);
792 for (i = 0; i < count; i++, sg++) {
793 addr = (void *) get_zeroed_page(GFP_KERNEL);
795 zfcp_sg_free_table(sg, i);
798 sg_set_buf(sg, addr, PAGE_SIZE);