Enhance SCST user space device handler interface for better compatibility older release #187
Description
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