Re: [PATCH] Do not round per_cpu_ptr_to_phys to page boundary

From: Petr Tesarik
Date: Fri Dec 16 2011 - 03:40:28 EST


Ignore my patch. I can see, a patch has already been accepted.

I only replied too fast (before I read the rest of the thread).

Petr

Dne Pá 16. prosince 2011 09:04:23 Petr Tesarik napsal(a):
> The phys_addr_t per_cpu_ptr_to_phys() function ignores the offset within a
> page, whenever not using a simple translation using __pa().
>
> Without this patch /sys/devices/system/cpu/cpu*/crash_notes shows incorrect
> values, which breaks kdump. Other things may also be broken.
>
> Signed-off-by: Petr Tesarik <ptesarik@xxxxxxx>
>
> diff --git a/mm/percpu.c b/mm/percpu.c
> index 3bb810a..1a1b5ac 100644
> --- a/mm/percpu.c
> +++ b/mm/percpu.c
> @@ -998,6 +998,7 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr)
> bool in_first_chunk = false;
> unsigned long first_low, first_high;
> unsigned int cpu;
> + phys_addr_t page_addr;
>
> /*
> * The following test on unit_low/high isn't strictly
> @@ -1023,9 +1024,10 @@ phys_addr_t per_cpu_ptr_to_phys(void *addr)
> if (!is_vmalloc_addr(addr))
> return __pa(addr);
> else
> - return page_to_phys(vmalloc_to_page(addr));
> + page_addr = page_to_phys(vmalloc_to_page(addr));
> } else
> - return page_to_phys(pcpu_addr_to_page(addr));
> + page_addr = page_to_phys(pcpu_addr_to_page(addr));
> + return page_addr + offset_in_page(addr);
> }
>
> /**
>
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