Clarification regarding copy_from_user
March 22, 2011 09:10AM

Please refer to the code: include/asm-generic/uaccess.h
Go to the definition of copy_from _user

The function copy_from_user accepts 3 parameters. What is the 3rd parameter - "unsigned long n" for? Should 'n' contain the number of characters to be read from the user buffer? My confusion stems from the code __copy(to, from, n) where there is a switch case implemented on 'n'.

I hope you will help me overcome my confusion by answering my question.

Yours faithfully,


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