Linux下的SCSI设备都是按照设备的发现顺序命名的，对于磁盘盘符名称就是sda，sdb，sdc等等。存储设备一般都配有很多块磁盘，盘符名称和槽位号没有对应关系，当磁盘插入，拔出时对应的盘符可能会变化。这给使用和运维带来很多不便。

对于SATA磁盘可通过修改sd_mod模块中的sd_probe(drivers/scsi/sd.c)来完成“磁盘槽位和盘符”的绑定。

/**

*sd_probe - called during driver initialization and whenever a

*new scsi device is attached to the system. It is called once

*for each scsi device (not just disks) present.

*@dev: pointer to device object

*

*Returns 0 if successful (or not interested in this scsi device

*(e.g. scanner)); 1 when there is an error.

*

*Note: this function is invoked from the scsi mid-level.

*This function sets up the mapping between a given

* (found in sdp) and new device name

*(e.g. /dev/sda). More precisely it is the block device major

*and minor number that is chosen here.

*

*Assume sd_attach is not re-entrant (for time being)

*Also think about sd_attach() and sd_remove() running coincidentally.

**/

static int sd_probe(struct device *dev)

{

struct scsi_device *sdp = to_scsi_device(dev);

struct scsi_disk *sdkp;

struct gendisk *gd;

u32 index;

int error;

error = -ENODEV;

if (sdp->type != TYPE_DISK && sdp->type != TYPE_MOD && sdp->type != TYPE_RBC)

goto out;

SCSI_LOG_HLQUEUE(3, sdev_printk(KERN_INFO, sdp,

"sd_attach\n"));

error = -ENOMEM;

sdkp = kzalloc(sizeof(*sdkp), GFP_KERNEL);

if (!sdkp)

goto out;

gd = alloc_disk(SD_MINORS);

if (!gd)

goto out_free;

do {

if (!ida_pre_get(&sd_index_ida, GFP_KERNEL))

goto out_put;

spin_lock(&sd_index_lock);

error = ida_get_new(&sd_index_ida, &index);

spin_unlock(&sd_index_lock);

} while (error == -EAGAIN);

if (error)

goto out_put;

if (index >= SD_MAX_DISKS) {

error = -ENODEV;

sdev_printk(KERN_WARNING, sdp, "SCSI disk (sd) name space exhausted.\n");

goto out_free_index;

}

error = sd_format_disk_name("sd", index, gd->disk_name, DISK_NAME_LEN);

if (error)

goto out_free_index;

......

}

具体负责给gendisk分配磁盘名称的就是 sd_format_disk_name，只需修改这个函数即可。为了完成槽位和盘符绑定我们需要一个对应表，这张表可以根据系统中的一些不变量，如磁盘的SCSI host号来确定对应关系。

如下是笔者根据scsi host(针对某款特定主板)确定盘符对应关系的Patch：

error = sd_format_disk_name("sd", sdp->host->host_no, gd->disk_name, DISK_NAME_LEN);

static int sd_format_disk_name(char *prefix, int host_no, char *buf, int buflen)

{

char *begin = buf + strlen(prefix);

*begin = 'a' + host_no;

*(begin + 1) = '\0';

memcpy(buf, prefix, strlen(prefix));

return 0;

}

作者：sage meng

出处：http://blog.csdn.net/lkkey80/article/details/50263083