On Fri, Aug 29, 2008 at 3:20 PM, Andrew Morton

 wrote:

quoted text
> On Fri, 29 Aug 2008 15:07:49 -0700

> Yinghai Lu  wrote:

>

>> +             printk(KERN_DEBUG "per_cpu_dyn_array %pF ==> [%#lx - %#lx]\n",

>> +                     da->name, phys, phys + size);

>

> This:

>

> struct dyn_array {

>        void **name;

>

> is a bit confusing.  One normally expects a variable called "name" to

> point at a character string.

>

> What _does_ this thing point at?  There are no code comments which I

> can find, it's unobvious from the source code, the type is the

> information-free void** and the identifier is misleading.

>

> I find that documenting the data structures is the best way of making

> code understandable (and hence maintainable).

struct dyn_array {

        void **name;

        unsigned long size;

        unsigned int *nr;

        unsigned long align;

        void (*init_work)(void *);

};

extern struct dyn_array *__dyn_array_start[], *__dyn_array_end[];

extern struct dyn_array *__per_cpu_dyn_array_start[],

*__per_cpu_dyn_array_end[];
#define DEFINE_DYN_ARRAY_ADDR(nameX, addrX, sizeX, nrX, alignX, init_workX) \

                static struct dyn_array __dyn_array_##nameX __initdata = \

                {       .name = (void **)&(nameX),\

                        .size = sizeX,\

                        .nr   = &(nrX),\

                        .align = alignX,\

                        .init_work = init_workX,\

                }; \

                static struct dyn_array *__dyn_array_ptr_##nameX __used \

                __attribute__((__section__(".dyn_array.init"))) = \

                        &__dyn_array_##nameX
#define DEFINE_DYN_ARRAY(nameX, sizeX, nrX, alignX, init_workX) \

        DEFINE_DYN_ARRAY_ADDR(nameX, nameX, sizeX, nrX, alignX, init_workX)
and use is
struct irq_desc *sparse_irqs;

DEFINE_DYN_ARRAY(sparse_irqs, sizeof(struct irq_desc), nr_irq_desc,

PAGE_SIZE, init_work);
then sparse_irqs is pointer, and .name store the address of that pointer.
later use

*da->name = phys_to_virt(phys);

to take back the dyn address.
YH

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