[PATCH] PowerPC: kernel: need return the related error code when failure occurs.

[Paul Mackerras]

On Tue, May 21, 2013 at 01:48:58PM +0800, Chen Gang wrote:
> 
> When error occurs, need return the related error code to let upper
> caller know about it.
> 
> ppc_md.nvram_size() can return the error code (e.g. core99_nvram_size()
> in 'arch/powerpc/platforms/powermac/nvram.c').
> 
> And when '*ppos >= size', need return -ESPIPE (Illegal seek)

Why?  When *ppos >= size, it should return 0 (end of file) in my opinion.
ESPIPE means that any seek would be ineffective, not that a particular
seek went out of bounds.

Paul.