Hi 
        The report link for this issue is: 
https://bugzilla.suse.com/show_bug.cgi?id=1092687

Thanks and regards

> -----Original Message-----
> From: Bjorn Helgaas [mailto:[email protected]]
> Sent: 2018年6月23日 7:20
> To: Guomin Chen <[email protected]>
> Cc: Brijesh Singh <[email protected]>; Tom Lendacky
> <[email protected]>; Yaowei Bai
> <[email protected]>; Bjorn Helgaas <[email protected]>;
> Toshi Kani <[email protected]>; Dan Williams <[email protected]>;
> Thomas Gleixner <[email protected]>; Andrew Morton
> <[email protected]>; Joey Lee <[email protected]>; Borislav Petkov
> <[email protected]>; Takashi Iwai <[email protected]>; [email protected];
> [email protected]
> Subject: Re: [PATCH 1/1] resource: Fixed iomem resource release failed on
> release_mem_region_adjustable() when memory node or cpu node
> hot-remove.
> 
> [+cc Toshi]
> 
> On Fri, Jun 22, 2018 at 08:01:38PM +0800, guomin chen wrote:
> > We've got a bug report indicating the hot-remove node resource release
> > failed,when the memory on this node is divided into several
> > sections.because the release_mem_region_adjustable() can only release
> > one resource that must be [start,end].
> 
> Can you please include a URL for the bug report?  That's useful for additional
> details and gives hints about how future changes in this area might be tested.
> 
> release_mem_region_adjustable() and the only call to it were added by Toshi
> (cc'd):
> 
>   825f787bb496 ("resource: add release_mem_region_adjustable()")
>   fe74ebb106a5 ("mm: change __remove_pages() to call
> release_mem_region_adjustable()")
> 
> > In my case, the BIOS supports faulty memory isolation. if BIOS
> > detected bad memory block, the BIOS will isolates this badblock.
> > And set this badblock memory to EfiUnusableMemory in EFI memory map
> > base on UEFI 2.7 spec.For example in my system, the memory range on
> > node2 is [mem 0x0000080000000000-0x00000807ffffffff].but the BIOS
> > detected the [8004e000000-8004e0fffff] is a badblock memory.
> > So the memory on node2 seem like this:
> >             80000000000-8004dffffff : System RAM
> >             8004e000000-8004e0fffff : Unusable memory
> >             8004e100000-807ffffffff : System RAM
> >
> > Now, when offline the cpu node2,the kernel will try to release
> > ioresource [mem 0x0000080000000000-0x00000807ffffffff]. at this time,
> > the kernel will release failed,and output error message:
> > "Unable to release resource <0x0000080000000000-0x00000807ffffffff>
> > (-22)".
> > Because the release_mem_region_adjustable() can only release one
> > resource that must be [0x0000080000000000 , 0x00000807ffffffff].
> > but now,the iomem resource on node2 [0x0000080000000000,
> > 0x00000807ffffffff] are divided into three resources [80000000000-
> > 8004dffffff],[8004e000000-8004e0fffff]and[8004e100000-807ffffffff].
> >
> > This patch help to Release multiple iomem resources at once when node
> > hot-remove. Such as in above case, when hot-remove the cpu node2,the
> > kernel will try to release resource [0x0000080000000000-
> > 0x00000807ffffffff].And this patch will release three resources
> > [80000000000-8004dffffff],[8004e000000-8004e0fffff] and
> > [8004e100000-807ffffffff].
> >
> > Cc: Thomas Gleixner <[email protected]>
> > Cc: Brijesh Singh <[email protected]>
> > Cc: Borislav Petkov <[email protected]>
> > Cc: Andrew Morton <[email protected]>
> > Cc: Tom Lendacky <[email protected]>
> > Cc: Bjorn Helgaas <[email protected]>
> > Cc: Yaowei Bai <[email protected]>
> > Cc: Takashi Iwai <[email protected]>
> > Cc: Dan Williams <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: Lee Chun-Yi <[email protected]>
> > Signed-off-by: guomin chen <[email protected]>
> > ---
> >  kernel/resource.c | 73
> > ++++++++++++++++++++++++++++++++-----------------------
> >  1 file changed, 43 insertions(+), 30 deletions(-)
> >
> > diff --git a/kernel/resource.c b/kernel/resource.c index
> > 30e1bc68503b..959bcce4c405 100644
> > --- a/kernel/resource.c
> > +++ b/kernel/resource.c
> > @@ -1240,6 +1240,7 @@ int release_mem_region_adjustable(struct
> resource *parent,
> >     struct resource *res;
> >     struct resource *new_res;
> >     resource_size_t end;
> > +   resource_size_t new_start = start;
> >     int ret = -EINVAL;
> >
> >     end = start + size - 1;
> > @@ -1257,7 +1258,7 @@ int release_mem_region_adjustable(struct
> resource *parent,
> >                     break;
> >
> >             /* look for the next resource if it does not fit into */
> > -           if (res->start > start || res->end < end) {
> > +           if (res->end < new_start) {
> >                     p = &res->sibling;
> >                     continue;
> >             }
> > @@ -1271,42 +1272,54 @@ int release_mem_region_adjustable(struct
> resource *parent,
> >             }
> >
> >             /* found the target resource; let's adjust accordingly */
> > -           if (res->start == start && res->end == end) {
> > +           if (res->start == new_start && res->end == end) {
> >                     /* free the whole entry */
> >                     *p = res->sibling;
> >                     free_resource(res);
> >                     ret = 0;
> > -           } else if (res->start == start && res->end != end) {
> > -                   /* adjust the start */
> > -                   ret = __adjust_resource(res, end + 1,
> > -                                           res->end - end);
> > -           } else if (res->start != start && res->end == end) {
> > -                   /* adjust the end */
> > -                   ret = __adjust_resource(res, res->start,
> > -                                           start - res->start);
> > +           } else if (res->end > end) {
> > +                   if (res->start >= new_start) {
> > +                           /* adjust the start */
> > +                           ret = __adjust_resource(res, end + 1,
> > +                                                   res->end - end);
> > +                   } else {
> > +                           /* split into two entries */
> > +                           if (!new_res) {
> > +                                   ret = -ENOMEM;
> > +                                   break;
> > +                           }
> > +                           new_res->name = res->name;
> > +                           new_res->start = end + 1;
> > +                           new_res->end = res->end;
> > +                           new_res->flags = res->flags;
> > +                           new_res->desc = res->desc;
> > +                           new_res->parent = res->parent;
> > +                           new_res->sibling = res->sibling;
> > +                           new_res->child = NULL;
> > +
> > +                           ret = __adjust_resource(res, res->start,
> > +                                                   new_start - res->start);
> > +                           if (ret)
> > +                                   break;
> > +                           res->sibling = new_res;
> > +                           new_res = NULL;
> > +                   }
> >             } else {
> > -                   /* split into two entries */
> > -                   if (!new_res) {
> > -                           ret = -ENOMEM;
> > -                           break;
> > +                   if (res->start < new_start) {
> > +                           /* adjust the end */
> > +                           ret = __adjust_resource(res, res->start,
> > +                                                   new_start - res->start);
> > +                           new_start = res->end+1;
> > +                           p = &res->sibling;
> > +                   } else {
> > +                           new_start = res->end+1;
> > +                           *p = res->sibling;
> > +                           free_resource(res);
> > +                           ret = 0;
> >                     }
> > -                   new_res->name = res->name;
> > -                   new_res->start = end + 1;
> > -                   new_res->end = res->end;
> > -                   new_res->flags = res->flags;
> > -                   new_res->desc = res->desc;
> > -                   new_res->parent = res->parent;
> > -                   new_res->sibling = res->sibling;
> > -                   new_res->child = NULL;
> > -
> > -                   ret = __adjust_resource(res, res->start,
> > -                                           start - res->start);
> > -                   if (ret)
> > -                           break;
> > -                   res->sibling = new_res;
> > -                   new_res = NULL;
> > +                   if (res->end < end)
> > +                           continue;
> >             }
> > -
> >             break;
> >     }
> >
> > --
> > 2.12.3
> >

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