Re: [PATCH] intel: igb: igb_ethtool.c: Convert kmap() to kmap_local_page()

[Alaa Mohamed]

On ١٥‏/٤‏/٢٠٢٢ ٢٣:٤٠, Ira Weiny wrote:
> On Fri, Apr 15, 2022 at 10:53:07PM +0200, Alaa Mohamed wrote:
> > The use of kmap() is being deprecated in favor of kmap_local_page()
> > where it is feasible.
> >
> > With kmap_local_page(), the mapping is per thread, CPU local and not
> > globally visible.
> >
> > Signed-off-by: Alaa Mohamed <eng.alaamohamedsoliman.am@xxxxxxxxx>
> > ---
> >   drivers/net/ethernet/intel/igb/igb_ethtool.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/intel/igb/igb_ethtool.c b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > index 2a5782063f4c..ba93aa4ae6a0 100644
> > --- a/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > +++ b/drivers/net/ethernet/intel/igb/igb_ethtool.c
> > @@ -1798,14 +1798,14 @@ static int igb_check_lbtest_frame(struct igb_rx_buffer *rx_buffer,
> >   
> >   	frame_size >>= 1;
> >   
> > -	data = kmap(rx_buffer->page);
> > +	data = kmap_local_page(rx_buffer->page);
> >   
> >   	if (data[3] != 0xFF ||
> >   	    data[frame_size + 10] != 0xBE ||
> >   	    data[frame_size + 12] != 0xAF)
> >   		match = false;
> >   
> > -	kunmap(rx_buffer->page);
> > +	kunmap_local(rx_buffer->page);
> kunmap_local() is different from kunmap().  It takes an address within the
> mapped page.  From the kdoc:
>
> /**
>   * kunmap_local - Unmap a page mapped via kmap_local_page().
>   * @__addr: An address within the page mapped
>   *
>   * @__addr can be any address within the mapped page.  Commonly it is the
>   * address return from kmap_local_page(), but it can also include offsets.
>   *
>   * Unmapping should be done in the reverse order of the mapping.  See
>   * kmap_local_page() for details.
>   */
> #define kunmap_local(__addr)                                    \
> ...
Got it , Thanks
> Ira
>
> >   
> >   	return match;
> >   }
> > --
> > 2.35.2