| Message ID | 1402475019-19699-4-git-send-email-zhong@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 06/11/2014 03:23 AM, Li Zhong wrote: > vmemmap_populated() checks whether the [start, start + page_size) has valid > pfn numbers, to know whether a vmemmap mapping has been created that includes > this range. > > Some range before end might not be checked by this loop: > sec11start......start11..sec11end/sec12start..end....start12..sec12end > as the above, for start11(section 11), it checks [sec11start, sec11end), and > loop ends as the next start(start12) is bigger than end. However, > [sec11end/sec12start, end) is not checked here. > > So before the loop, adjust the start to be the start of the section, so we don't miss ranges like the above. > > After we adjust start to be the start of the section, it also means it's > aligned with vmemmap as of the sizeof struct page, so we could use > page_to_pfn directly in the loop. > > Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> > Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com> Acked-by: Nathan Fontenot <nfont@linux.vnet.ibm.com> > --- > arch/powerpc/mm/init_64.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c > index 4963790..253b4b9 100644 > --- a/arch/powerpc/mm/init_64.c > +++ b/arch/powerpc/mm/init_64.c > @@ -175,9 +175,10 @@ static unsigned long __meminit vmemmap_section_start(unsigned long page) > static int __meminit vmemmap_populated(unsigned long start, int page_size) > { > unsigned long end = start + page_size; > + start = (unsigned long)(pfn_to_page(vmemmap_section_start(start))); > > for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) > - if (pfn_valid(vmemmap_section_start(start))) > + if (pfn_valid(page_to_pfn((struct page *)start))) > return 1; > > return 0; >
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c index 4963790..253b4b9 100644 --- a/arch/powerpc/mm/init_64.c +++ b/arch/powerpc/mm/init_64.c @@ -175,9 +175,10 @@ static unsigned long __meminit vmemmap_section_start(unsigned long page) static int __meminit vmemmap_populated(unsigned long start, int page_size) { unsigned long end = start + page_size; + start = (unsigned long)(pfn_to_page(vmemmap_section_start(start))); for (; start < end; start += (PAGES_PER_SECTION * sizeof(struct page))) - if (pfn_valid(vmemmap_section_start(start))) + if (pfn_valid(page_to_pfn((struct page *)start))) return 1; return 0;
vmemmap_populated() checks whether the [start, start + page_size) has valid pfn numbers, to know whether a vmemmap mapping has been created that includes this range. Some range before end might not be checked by this loop: sec11start......start11..sec11end/sec12start..end....start12..sec12end as the above, for start11(section 11), it checks [sec11start, sec11end), and loop ends as the next start(start12) is bigger than end. However, [sec11end/sec12start, end) is not checked here. So before the loop, adjust the start to be the start of the section, so we don't miss ranges like the above. After we adjust start to be the start of the section, it also means it's aligned with vmemmap as of the sizeof struct page, so we could use page_to_pfn directly in the loop. Signed-off-by: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Nathan Fontenot <nfont@linux.vnet.ibm.com> --- arch/powerpc/mm/init_64.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)