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    Subject[PATCCH percpu: add cpunum param in per_cpu_ptr_to_phys
    per_cpu_ptr_to_phys iterate all cpu to get the phy addr
    let's leave the caller to pass the cpu number to it.

    Actually in the only one user show_crash_notes,
    cpunum is provided already before calling this.

    Signed-off-by: Dave Young <dyoung@redhat.com>
    ---
    drivers/base/cpu.c | 2 +-
    include/linux/percpu.h | 2 +-
    mm/percpu.c | 29 ++++-------------------------
    3 files changed, 6 insertions(+), 27 deletions(-)

    --- linux-2.6.orig/drivers/base/cpu.c 2011-09-20 12:39:36.000000000 +0800
    +++ linux-2.6/drivers/base/cpu.c 2011-11-15 14:52:42.742852411 +0800
    @@ -125,7 +125,7 @@ static ssize_t show_crash_notes(struct s
    * boot up and this data does not change there after. Hence this
    * operation should be safe. No locking required.
    */
    - addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum));
    + addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpunum), cpunum);
    rc = sprintf(buf, "%Lx\n", addr);
    return rc;
    }
    --- linux-2.6.orig/include/linux/percpu.h 2011-11-15 11:06:18.000000000 +0800
    +++ linux-2.6/include/linux/percpu.h 2011-11-15 14:53:28.352605321 +0800
    @@ -160,7 +160,7 @@ extern void __init percpu_init_late(void

    extern void __percpu *__alloc_percpu(size_t size, size_t align);
    extern void free_percpu(void __percpu *__pdata);
    -extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
    +extern phys_addr_t per_cpu_ptr_to_phys(void *addr, int cpunum);

    #define alloc_percpu(type) \
    (typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))
    --- linux-2.6.orig/mm/percpu.c 2011-11-15 11:06:19.000000000 +0800
    +++ linux-2.6/mm/percpu.c 2011-11-15 14:59:56.927166899 +0800
    @@ -971,6 +971,7 @@ bool is_kernel_percpu_address(unsigned l
    /**
    * per_cpu_ptr_to_phys - convert translated percpu address to physical address
    * @addr: the address to be converted to physical address
    + * @cpunum: the cpu number of percpu address
    *
    * Given @addr which is dereferenceable address obtained via one of
    * percpu access macros, this function translates it into its physical
    @@ -980,34 +981,12 @@ bool is_kernel_percpu_address(unsigned l
    * RETURNS:
    * The physical address for @addr.
    */
    -phys_addr_t per_cpu_ptr_to_phys(void *addr)
    +phys_addr_t per_cpu_ptr_to_phys(void *addr, int cpunum)
    {
    void __percpu *base = __addr_to_pcpu_ptr(pcpu_base_addr);
    - bool in_first_chunk = false;
    - unsigned long first_start, first_end;
    - unsigned int cpu;
    + void *start = per_cpu_ptr(base, cpunum);

    - /*
    - * The following test on first_start/end isn't strictly
    - * necessary but will speed up lookups of addresses which
    - * aren't in the first chunk.
    - */
    - first_start = pcpu_chunk_addr(pcpu_first_chunk, pcpu_first_unit_cpu, 0);
    - first_end = pcpu_chunk_addr(pcpu_first_chunk, pcpu_last_unit_cpu,
    - pcpu_unit_pages);
    - if ((unsigned long)addr >= first_start &&
    - (unsigned long)addr < first_end) {
    - for_each_possible_cpu(cpu) {
    - void *start = per_cpu_ptr(base, cpu);
    -
    - if (addr >= start && addr < start + pcpu_unit_size) {
    - in_first_chunk = true;
    - break;
    - }
    - }
    - }
    -
    - if (in_first_chunk) {
    + if (addr >= start && addr < start + pcpu_unit_size) {
    if (!is_vmalloc_addr(addr))
    return __pa(addr);
    else

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