The patch titled
Subject: mm/sparse: clarify pgdat_to_phys
has been added to the -mm tree. Its filename is
mm-sparse-clarify-pgdat_to_phys.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-sparse-clarify-pgdat_to_phys.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-sparse-clarify-pgdat_to_phys.patch
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------------------------------------------------------
From: Miles Chen <miles.chen@xxxxxxxxxxxx>
Subject: mm/sparse: clarify pgdat_to_phys
Clarify pgdat_to_phys() by testing if
pgdat == &contig_page_data when CONFIG_NUMA=n.
We only expect contig_page_data in such case, so we
use &contig_page_data directly instead of pgdat.
No functional change intended when CONFIG_BUG_VM=n.
Comment from Mark [1]:
"
... and I reckon it'd be clearer and more robust to define
pgdat_to_phys() in the same ifdefs as contig_page_data so
that these, stay in-sync. e.g. have:
| #ifdef CONFIG_NUMA
| #define pgdat_to_phys(x) virt_to_phys(x)
| #else /* CONFIG_NUMA */
|
| extern struct pglist_data contig_page_data;
| ...
| #define pgdat_to_phys(x) __pa_symbol(&contig_page_data)
|
| #endif /* CONIFIG_NUMA */
"
[1] https://lore.kernel.org/linux-arm-kernel/20210615131902.GB47121@C02TD0UTHF1T.local/
Link: https://lkml.kernel.org/r/20210723123342.26406-1-miles.chen@xxxxxxxxxxxx
Signed-off-by: Miles Chen <miles.chen@xxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/sparse.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/sparse.c~mm-sparse-clarify-pgdat_to_phys
+++ a/mm/sparse.c
@@ -321,7 +321,8 @@ size_t mem_section_usage_size(void)
static inline phys_addr_t pgdat_to_phys(struct pglist_data *pgdat)
{
#ifndef CONFIG_NUMA
- return __pa_symbol(pgdat);
+ VM_BUG_ON(pgdat != &contig_page_data);
+ return __pa_symbol(&contig_page_data);
#else
return __pa(pgdat);
#endif
_
Patches currently in -mm which might be from miles.chen@xxxxxxxxxxxx are
mm-sparse-clarify-pgdat_to_phys.patch
