[v1,1/4] resource: Use PFN_UP / PFN_DOWN in walk_system_ram_range()
diff mbox series

Message ID 20190809125701.3316-2-david@redhat.com
State Superseded
Commit 603729ab4d82619d3163b349b4e090c178dcea5b
Headers show
Series
  • mm/memory_hotplug: online_pages() cleanups
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Commit Message

David Hildenbrand Aug. 9, 2019, 12:56 p.m. UTC
This makes it clearer that we will never call func() with duplicate PFNs
in case we have multiple sub-page memory resources. All unaligned parts
of PFNs are completely discarded.

Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 kernel/resource.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Michal Hocko Aug. 14, 2019, 2:06 p.m. UTC | #1
On Fri 09-08-19 14:56:58, David Hildenbrand wrote:
> This makes it clearer that we will never call func() with duplicate PFNs
> in case we have multiple sub-page memory resources. All unaligned parts
> of PFNs are completely discarded.
> 
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Borislav Petkov <bp@suse.de>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Nadav Amit <namit@vmware.com>
> Cc: Wei Yang <richardw.yang@linux.intel.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Signed-off-by: David Hildenbrand <david@redhat.com>

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  kernel/resource.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/resource.c b/kernel/resource.c
> index 7ea4306503c5..88ee39fa9103 100644
> --- a/kernel/resource.c
> +++ b/kernel/resource.c
> @@ -487,8 +487,8 @@ int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
>  	while (start < end &&
>  	       !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
>  				    false, &res)) {
> -		pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
> -		end_pfn = (res.end + 1) >> PAGE_SHIFT;
> +		pfn = PFN_UP(res.start);
> +		end_pfn = PFN_DOWN(res.end + 1);
>  		if (end_pfn > pfn)
>  			ret = (*func)(pfn, end_pfn - pfn, arg);
>  		if (ret)
> -- 
> 2.21.0

Patch
diff mbox series

diff --git a/kernel/resource.c b/kernel/resource.c
index 7ea4306503c5..88ee39fa9103 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -487,8 +487,8 @@  int walk_system_ram_range(unsigned long start_pfn, unsigned long nr_pages,
 	while (start < end &&
 	       !find_next_iomem_res(start, end, flags, IORES_DESC_NONE,
 				    false, &res)) {
-		pfn = (res.start + PAGE_SIZE - 1) >> PAGE_SHIFT;
-		end_pfn = (res.end + 1) >> PAGE_SHIFT;
+		pfn = PFN_UP(res.start);
+		end_pfn = PFN_DOWN(res.end + 1);
 		if (end_pfn > pfn)
 			ret = (*func)(pfn, end_pfn - pfn, arg);
 		if (ret)