Linux内核SCSI子系统驱动架构资料.docx

1、Linux内核SCSI子系统驱动架构资料SCSI子系统驱动架构 2013-2-2代码布局：一、读写数据流：drivers/scsi/scsi_lib.cscsi_execute_req=scsi_execute=blk_execute_rq=blk_execute_rq_nowait错误恢复:drivers/scsi/scsi_error.c内核线程scsi_error_handler=二、初始化：(本文！)-scsi高层（scsi磁盘）驱动：1代码分布2核心调用：drivers/scsi/sd.c（这里以scsi disk设备为例）同步执行部分：sd_probe异步执行部分：sd_probe

2、_async=sd_revalidate_disk=sd_spinup_disk-scsi子系统核心初始化：1代码分布2核心调用：scsi_init_queue();scsi_init_procfs();scsi_init_devinfo();scsi_init_hosts();scsi_init_sysctl();scsi_sysfs_register(); scsi_netlink_init();-scsi适配器驱动：1代码分布2核心调用：drivers/scsi/hosts.c1）、struct Scsi_Host *scsi_host_alloc(struct scsi_host_te

3、mplate *sht, int privsize) 2）、scsi_add_host(struct Scsi_Host *host,struct device *dev)=scsi_add_host_with_dma(host, dev, dev)int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, struct device *dma_dev)3）、scsi_scan_host=do_scsi_scan_host=scsi_scan_host_selected=scsi_scan_channel =_

4、scsi_scan_target=scsi_probe_and_add_lun=scsi_probe_lun scsi_add_lun代码骨架：-scsi子系统核心初始化：drivers/scsi/scsi.c:static struct class shost_class = .name = scsi_host, .dev_release = scsi_host_cls_release,;static struct class sdev_class = .name = scsi_device, .dev_release = scsi_device_cls_release,;struct bu

5、s_type scsi_bus_type = .name = scsi, .match = scsi_bus_match, .uevent = scsi_bus_uevent,;subsys_initcall(init_scsi)=static int _init init_scsi(void) scsi_init_queue(); scsi_init_procfs(); scsi_init_devinfo();/ scsi_init_hosts();/ scsi_init_sysctl(); scsi_sysfs_register();/ scsi_netlink_init();int sc

6、si_init_hosts(void) return class_register(&shost_class);int scsi_sysfs_register(void)int error; error = bus_register(&scsi_bus_type); if (!error) class_register(&sdev_class); - scsi HBA驱动：（前端以dmx3191d为例）static struct scsi_host_template dmx3191d_driver_template = .name = Domex DMX3191D, .queuecommand

7、 = NCR5380_queue_command,. .,;static struct pci_device_id dmx3191d_pci_tbl = PCI_VENDOR_ID_DOMEX, PCI_DEVICE_ID_DOMEX_DMX3191D, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 4, ;static struct pci_driver dmx3191d_pci_driver = .name = DMX3191D_DRIVER_NAME, .id_table = dmx3191d_pci_tbl, .probe = dmx3191d_probe_one, .r

8、emove = _devexit_p(dmx3191d_remove_one),;module_init(dmx3191d_init);static int _init dmx3191d_init(void) return pci_register_driver(&dmx3191d_pci_driver);/调dmx3191d_probe_onestatic int _devinit dmx3191d_probe_one(struct pci_dev *pdev, const struct pci_device_id *id) struct Scsi_Host *shost;. .; scsi

9、_host_alloc(&dmx3191d_driver_template,sizeof(struct NCR5380_hostdata);/- shost-irq = pdev-irq;request_irq(pdev-irq, NCR5380_intr, IRQF_SHARED,NAME, shost); . .; scsi_add_host(shost, &pdev-dev); scsi_scan_host(shost);-drivers/scsi/hosts.cstatic atomic_t scsi_host_next_hn; struct Scsi_Host *scsi_host_

10、alloc(struct scsi_host_template *sht, int privsize) struct Scsi_Host *shost; gfp_t gfp_mask = GFP_KERNEL; shost = kzalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask); shost-host_no = atomic_inc_return(&scsi_host_next_hn) - 1; device_initialize(&shost-shost_gendev); shost-shost_gendev.bus = &scsi_

11、bus_type; shost-shost_gendev.type = &scsi_host_type;. .; device_initialize(&shost-shost_dev); shost-shost_dev.parent = &shost-shost_gendev; shost-shost_dev.class = &shost_class; return shost;include/scsi/scsi_host.hstatic inline int _must_check scsi_add_host(struct Scsi_Host *host, struct device *de

12、v) return scsi_add_host_with_dma(host, dev, dev);drivers/scsi/hosts.cint scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, struct device *dma_dev) struct scsi_host_template *sht = shost-hostt;. .; device_add(&shost-shost_gendev);/- device_add(&shost-shost_dev);. .;scsi_sysfs_add_ho

13、st(shost);. .;-drivers/scsi/scsi_scan.c#ifdef CONFIG_SCSI_SCAN_ASYNC /0#define SCSI_SCAN_TYPE_DEFAULT async#else#define SCSI_SCAN_TYPE_DEFAULT sync#endifstatic char scsi_scan_type6 = SCSI_SCAN_TYPE_DEFAULT;/变量的值可以在加载scsi中间层模块时通过模块参数设定，未设定则用上面的默认值module_param_string(scan, scsi_scan_type, sizeof(scsi_

14、scan_type), S_IRUGO);# define jiffies raid6_jiffies()/specify scanning or rescanning of all possible channels, (target) ids, or luns ,on a given shost.#define SCAN_WILD_CARD 0#define MAX_COMMAND_SIZE 16void scsi_scan_host(struct Scsi_Host *shost) struct task_struct *p; struct async_scan_data *data;

15、if (strncmp(scsi_scan_type, none, 4) = 0) return; data = scsi_prep_async_scan(shost);/异步扫描准备与判断 shost-async_scan = 1 if (!data) /如果data=null, shost-async_scan仍为0 do_scsi_scan_host(shost); return;/同步扫描逻辑，不需要任何准备工作 p = kthread_run(do_scan_async, data, scsi_scan_%d, shost-host_no);/异步扫描逻辑 if (IS_ERR(p)

16、/有错误时 do_scan_async(data);/shost-async_scan = 0static void do_scsi_scan_host(struct Scsi_Host *shost) if (shost-hostt-scan_finished) . .;/自定义的扫描逻辑 else /通配符SCAN_WILD_CARD 0 , 表示需要尝试所有可能的值/rescan=0，表示第一次扫描，为1，表示重新扫描，即这个接口还有其他地方调用！ scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD, SCAN_WI

17、LD_CARD, 0); int scsi_scan_host_selected(struct Scsi_Host *shost, unsigned int channel, unsigned int id, unsigned int lun, int rescan) . .;/shost-async_scan:是异步扫描标志，为1-异步扫描，0-同步扫描 if (!shost-async_scan) scsi_complete_async_scans();if (scsi_host_scan_allowed(shost) if (channel = SCAN_WILD_CARD) for (

18、channel = 0; channel max_channel; channel+) scsi_scan_channel(shost, channel, id, lun, rescan); else scsi_scan_channel(shost, channel, id, lun, rescan); static void scsi_scan_channel(struct Scsi_Host *shost, unsigned int channel, unsigned int id, unsigned int lun, int rescan) uint order_id; if (id =

19、 SCAN_WILD_CARD) for (id = 0; id max_id; +id) if (shost-reverse_ordering) order_id = shost-max_id - id - 1; else order_id = id; _scsi_scan_target(&shost-shost_gendev, channel, order_id, lun, rescan); else _scsi_scan_target(&shost-shost_gendev, channel, id, lun, rescan);/-static void _scsi_scan_targe

20、t(struct device *parent, unsigned int channel, unsigned int id, unsigned int lun, int rescan) struct Scsi_Host *shost = dev_to_shost(parent); int bflags = 0; int res; struct scsi_target *starget; if (shost-this_id = id) return; starget = scsi_alloc_target(parent, channel, id); if (lun != SCAN_WILD_C

21、ARD) scsi_probe_and_add_lun(starget, lun, NULL, NULL, rescan, NULL);/- goto out_reap; res = scsi_probe_and_add_lun(starget, 0, &bflags, NULL, rescan, NULL);/- if (res = SCSI_SCAN_LUN_PRESENT | res = SCSI_SCAN_TARGET_PRESENT) /会调用scsi_probe_and_add_lun if (scsi_report_lun_scan(starget, bflags, rescan

22、) != 0)/会调用scsi_probe_and_add_lun scsi_sequential_lun_scan(starget, bflags, starget-scsi_level, rescan); out_reap: scsi_target_reap(starget); put_device(&starget-dev);static int scsi_probe_and_add_lun(struct scsi_target *starget, uint lun, int *bflagsp, struct scsi_device *sdevp, int rescan, void *h

23、ostdata) struct scsi_device *sdev; unsigned char *result; int bflags, result_len = 256; struct Scsi_Host *shost = dev_to_shost(starget-dev.parent); sdev = scsi_device_lookup_by_target(starget, lun); if (sdev) if (rescan | !scsi_device_created(sdev) if (sdevp) *sdevp = sdev; else scsi_device_put(sdev

24、); if (bflagsp) *bflagsp = scsi_get_device_flags(sdev, sdev-vendor, sdev-model); return SCSI_SCAN_LUN_PRESENT; . .; else sdev = scsi_alloc_sdev(starget, lun, hostdata);/- result = kmalloc(result_len, GFP_ATOMIC | (shost-unchecked_isa_dma) ? _GFP_DMA : 0); scsi_probe_lun(sdev, result, result_len, &bf

25、lags);/- if (bflagsp) *bflagsp = bflags;. .; res = scsi_add_lun(sdev, result, &bflags, shost-async_scan);/-return res;static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget, unsigned int lun, void *hostdata) struct scsi_device *sdev; struct Scsi_Host *shost = dev_to_shost(starget-dev

26、.parent);. .; sdev = kzalloc(sizeof(*sdev) + shost-transportt-device_size, GFP_ATOMIC); . .; sdev-request_queue = scsi_alloc_queue(sdev); . .; scsi_sysfs_device_initialize(sdev);/-. .; return sdev;void scsi_sysfs_device_initialize(struct scsi_device *sdev) struct Scsi_Host *shost = sdev-host; struct scsi_target *starget = sdev-sdev_target; device_initialize(&sdev-sdev_gendev);/ sdev-sdev_gendev.bus = &scsi_bus_type; sdev-sdev_gendev.type = &scsi_dev_type;. .; device_initialize(&sdev-sdev_dev);/. .; sdev-scsi_level = starget-scsi_level;list_add_tail(&sdev-same_target_siblings, &starget-devi