Re: [PATCH 1/3] mcb: Use DEFINE_RES_MEM() to simplify code

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Jun 16, 2021 at 09:31:37AM +0800, Leizhen (ThunderTown) wrote:
> 
> 
> On 2021/6/15 23:42, Greg Kroah-Hartman wrote:
> > On Tue, Jun 15, 2021 at 11:55:28PM +0900, Johannes Thumshirn wrote:
> >> From: Zhen Lei <thunder.leizhen@huawei.com>
> >>
> >> The value of '.end' should be "start + size - 1". So the previous writing
> >> should have omitted subtracted 1.
> >>
> >> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> >> Signed-off-by: Johannes Thumshirn <jth@kernel.org>
> >> ---
> >>  drivers/mcb/mcb-lpc.c | 13 ++-----------
> >>  1 file changed, 2 insertions(+), 11 deletions(-)
> >>
> >> diff --git a/drivers/mcb/mcb-lpc.c b/drivers/mcb/mcb-lpc.c
> >> index 506676754538..53decd89876e 100644
> >> --- a/drivers/mcb/mcb-lpc.c
> >> +++ b/drivers/mcb/mcb-lpc.c
> >> @@ -105,17 +105,8 @@ static int mcb_lpc_create_platform_device(const struct dmi_system_id *id)
> >>  	return ret;
> >>  }
> >>  
> >> -static struct resource sc24_fpga_resource = {
> >> -	.start = 0xe000e000,
> >> -	.end = 0xe000e000 + CHAM_HEADER_SIZE,
> >> -	.flags = IORESOURCE_MEM,
> >> -};
> >> -
> >> -static struct resource sc31_fpga_resource = {
> >> -	.start = 0xf000e000,
> >> -	.end = 0xf000e000 + CHAM_HEADER_SIZE,
> >> -	.flags = IORESOURCE_MEM,
> >> -};
> >> +static struct resource sc24_fpga_resource = DEFINE_RES_MEM(0xe000e000, CHAM_HEADER_SIZE);
> >> +static struct resource sc31_fpga_resource = DEFINE_RES_MEM(0xf000e000, CHAM_HEADER_SIZE);
> > 
> > Does this simplify stuff, or does it fix a bug with the existing
> > definition?
> 
> It does not fix a bug, the actual value of .end should be "0xe000e000 + CHAM_HEADER_SIZE - 1".
> There is no functional problem, just a little more memory. So it's just been corrected in the
> process of simplification.
> 
> Do you think it's necessary to split it into two patches?

No need, I just want to know if this is a fix that needs to go to older
kernels as well.  The text was very vague.


thanks,

greg k-h