Enhance SCST user space device handler interface for better compatibility older release

[ssmuch]

Hi Team,

When upgrading the SCST version(to 3.7), we discover that the device handler(which compiled with scst 3.6 user space) is not compatible.

In the scst_user spect file and source file, the current logic, before dev_user_register_dev registering a device, it will check the protocol version: DEV_USER_VERSION, https://scst.sourceforge.net/scst_user_spec.pdf https://github.com/SCST-project/scst/blob/master/scst/src/dev_handlers/scst_user.c#L3265

And the DEV_USER_VERSION is defined by retrieving sha1sum value of $(SCST_INC_DIR)/scst_user.h, this hash value is different, even the changes of scst_user.h is very limited. https://github.com/SCST-project/scst/blob/master/scst/src/Makefile#L79

Could we enhance the DEV_USER_VERSION check logic for supporting older release device handler?

Here's the diff of scst_user.h/c file: bash-3.2$ diff scst-3.6/scst/include/scst_user.h scst-3.7/scst/include/scst_user.h 357c357 < struct scst_user_get_cmd cmds[0]; / out /

struct scst_user_get_cmd cmds[]; / out / bash-3.2$ diff scst-3.6/scst/src/dev_handlers/scst_user.c scst-3.7/scst/src/dev_handlers/scst_user.c 4123,4125d4122 < #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21) < struct class_device *class_member; < #else 4127d4123 < #endif 4177,4184d4172 < #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21) < class_member = class_device_create(dev_user_sysfs_class, NULL, < MKDEV(dev_user_major, 0), NULL, DEV_USER_NAME); < if (IS_ERR(class_member)) { < res = PTR_ERR(class_member); < goto out_chrdev; < } < #else 4187d4174 < #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27) 4189d4175 < #endif 4195d4180 < #endif 4210,4212d4194 < #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21) < class_device_destroy(dev_user_sysfs_class, MKDEV(dev_user_major, 0)); < #else 4214d4195 < #endif 4245,4247d4225 < #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 21) < class_device_destroy(dev_user_sysfs_class, MKDEV(dev_user_major, 0)); < #else 4249d4226 < #endif bash-3.2$ Thanks Kyle

[ssmuch]

Hi Team, could someone help to take a look? Could we enhance the DEV_USER_VERSION check logic for better supporting older release device handler?

thanks, Kyle

[ssmuch]

Hi Team, could someone help to take a look? Could we enhance the DEV_USER_VERSION check logic for better supporting older release device handler?

thanks, Kyle