On Thu, Jan 24, 2019 at 5:21 PM Dave Hansen <[email protected]> wrote: > > > From: Dave Hansen <[email protected]> > > walk_system_ram_range() can return an error code either becuase *it* > failed, or because the 'func' that it calls returned an error. The > memory hotplug does the following: > > ret = walk_system_ram_range(..., func); > if (ret) > return ret; > > and 'ret' makes it out to userspace, eventually. The problem is, > walk_system_ram_range() failues that result from *it* failing (as > opposed to 'func') return -1. That leads to a very odd -EPERM (-1) > return code out to userspace. > > Make walk_system_ram_range() return -EINVAL for internal failures to > keep userspace less confused. > > This return code is compatible with all the callers that I audited. > > Signed-off-by: Dave Hansen <[email protected]> > Cc: Dan Williams <[email protected]> > Cc: Dave Jiang <[email protected]> > Cc: Ross Zwisler <[email protected]> > Cc: Vishal Verma <[email protected]> > Cc: Tom Lendacky <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Michal Hocko <[email protected]> > Cc: [email protected] > Cc: [email protected] > Cc: [email protected] > Cc: Huang Ying <[email protected]> > Cc: Fengguang Wu <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: Bjorn Helgaas <[email protected]> > Cc: Yaowei Bai <[email protected]> > Cc: Takashi Iwai <[email protected]> > Cc: Jerome Glisse <[email protected]> > --- > > b/kernel/resource.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff -puN > kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 > kernel/resource.c > --- a/kernel/resource.c~memory-hotplug-walk_system_ram_range-returns-neg-1 > 2019-01-24 15:13:13.950199540 -0800 > +++ b/kernel/resource.c 2019-01-24 15:13:13.954199540 -0800 > @@ -375,7 +375,7 @@ static int __walk_iomem_res_desc(resourc > int (*func)(struct resource *, void *)) > { > struct resource res; > - int ret = -1; > + int ret = -EINVAL; > > while (start < end && > !find_next_iomem_res(start, end, flags, desc, first_lvl, > &res)) { > @@ -453,7 +453,7 @@ int walk_system_ram_range(unsigned long > unsigned long flags; > struct resource res; > unsigned long pfn, end_pfn; > - int ret = -1; > + int ret = -EINVAL;
Can you either make a similar change to the powerpc version of walk_system_ram_range() in arch/powerpc/mm/mem.c or explain why it's not needed? It *seems* like we'd want both versions of walk_system_ram_range() to behave similarly in this respect. > start = (u64) start_pfn << PAGE_SHIFT; > end = ((u64)(start_pfn + nr_pages) << PAGE_SHIFT) - 1; > _
