Scsi - Index of

可以看到这个函数的参数有一个是struct scsi_host_template 结构体的指针,而她将返回一个
struct Scsi_Host 结构体的指针,回想一下,前面咱们调用这个函数的那句,
790 us->host = scsi_host_alloc(&usb_stor_host_template, sizeof(us));
103
凭一种男人的直觉,可以猜出,这个函数申请了一个Scsi_Host 结构体,并返回指向她的指针赋给
us->host.从高一点的角度来说,这么一句话实际上就是在scsi 核心层注册了一个scsi 卡,当然这里的
scsi
卡是虚拟的.顺便来看看us->host.她实际上就是一个struct Scsi_Host 结构体的指针,而struct
Scsi_Host 又是一个变态的数据结构,她的定义在include/scsi/scsi_host.h 中:
376 struct Scsi_Host {
377 /*
378 * __devices is protected by the host_lock, but you should
379 * usually use scsi_device_lookup / shost_for_each_device
380 * to access it and don't care about locking yourself.
381 * In the rare case of beeing in irq context you can use
382 * their __ prefixed variants with the lock held. NEVER
383 * access this list directly from a driver.
384 */
385 struct list_head __devices;
386
387 struct scsi_host_cmd_pool *cmd_pool;
388 spinlock_t free_list_lock;
389 struct list_head free_list; /* backup store of cmd structs */
390 struct list_head starved_list;
391
392 spinlock_t default_lock;
393 spinlock_t *host_lock;
394
395 struct semaphore scan_mutex;/* serialize scanning activity */
396
397 struct list_head eh_cmd_q;
398 struct task_struct * ehandler; /* Error recovery thread. */
399 struct semaphore * eh_wait; /* The error recovery thread waits
400 on this. */
401 struct completion * eh_notify; /* wait for eh to begin or end */
402 struct semaphore * eh_action; /* Wait for specific actions on the
403 host. */
404 unsigned int eh_active:1; /* Indicates the eh thread is awake
and active if
405 this is true. */
406 unsigned int eh_kill:1; /* set when killing the eh thread */
407 wait_queue_head_t host_wait;
408 struct scsi_host_template *hostt;
409 struct scsi_transport_template *transportt;