When a large number of almost identical files is used, it's quite inconvenient to use a separate call back function for each file. A better approach is to have a single call back function that distinguishes between the files by using the data field in struct proc_dir_entry. First of all, the data field has to be initialised:
struct proc_dir_entry* entry; struct my_file_data *file_data; file_data = kmalloc(sizeof(struct my_file_data), GFP_KERNEL); entry->data = file_data; |
The data field is a void *, so it can be initialised with anything.
Now that the data field is set, the read_proc and write_proc can use it to distinguish between files because they get it passed into their data parameter:
int foo_read_func(char *page, char **start, off_t off, int count, int *eof, void *data) { int len; if(data == file_data) { /* special case for this file */ } else { /* normal processing */ } return len; } |
Be sure to free the data data field when removing the procfs entry.