Scsi - Index of

99 * one of the luns for the device at a
100 * time. */
101 unsigned was_reset:1; /* There was a bus reset on the bus for
102 * this device */
103 unsigned expecting_cc_ua:1; /* Expecting a
CHECK_CONDITION/UNIT_ATTN
104 * because we did a bus reset. */
105 unsigned use_10_for_rw:1; /* first try 10-byte read / write */
106 unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
107 unsigned skip_ms_page_8:1; /* do not use MODE SENSE page 0x08
*/
108 unsigned skip_ms_page_3f:1; /* do not use MODE SENSE page 0x3f */
109 unsigned use_192_bytes_for_3f:1; /* ask for 192 bytes from page 0x3f */
110 unsigned no_start_on_add:1; /* do not issue start on add */
111 unsigned allow_restart:1; /* issue START_UNIT in error handler */
112 unsigned no_uld_attach:1; /* disable connecting to upper level drivers */
113 unsigned select_no_atn:1;
114 unsigned fix_capacity:1; /* READ_CAPACITY is too high by 1 */
115
116 unsigned int device_blocked; /* Device returned QUEUE_FULL. */
117
118 unsigned int max_device_blocked; /* what device_blocked counts down
from */
119 #define SCSI_DEFAULT_DEVICE_BLOCKED 3
120
121 int timeout;
122
123 struct device sdev_gendev;
124 struct class_device sdev_classdev;
125
126 struct class_device transport_classdev;
127
128 enum scsi_device_state sdev_state;
129 unsigned long sdev_data[0];
130 } __attribute__((aligned(sizeof(unsigned long))));
这个结构体将在未来的日子里被我们多次提到.当然,此刻,我们只需要注意到unsigned int id, lun,
channel 这三个成员,这正是定位一个scsi 设备必要的三个成员,一个scsi 卡所控制的设备被划分为几
层,
先是若干个channel,然后每个channel 上有若干个target,每个target 用一个target id 来表征,然后一
个target 可以有若干个lun,而咱们这里判断的是target id.对于不支持多个target 的设备,她必须为0.
对于绝大多数usb mass storage 设备来说,它们的target id 肯定为0,但是世界上总是有那么多怪事,有
些设备厂家就是要标新立异,它就是要让你个设备支持多个target,于是它就可以设置
127
US_FL_SCM_MULT_TARG 这么一个flag,比如我们可以在drivers/usb/storage/unusual_devs.h