From: Arnd Bergmann <arnd@arndb.de>
To: Amit Ben Shahar <amit.bens@gmail.com>
Subject: Re: Why is the 'loff_t *offset' parameter in the file_operations' read function a pointer?
Date: Tue, 26 Apr 2011 14:37:53 +0200
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On Tuesday 26 April 2011, Amit Ben Shahar wrote:
> (if i'm off topic or should look elsewhere i apologize - couldn't find
> information anywhere)
> I am coding a kernel module and implementing a file's operations, the
> read operation received an loff_t *offset parameter, why is this a
> pointer? is it in userspace?

The read function must update the offset independent of the return value.
See simple_read_from_buffer() as an example.

	Arnd
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