[Xen-devel] Question about next_module() function

[조현권 <chkwon91@xxxxxxxxx>]

Hi

I am experimenting Xen with my embedded system environment and got a question in next_module() function.

static paddr_t __init next_module(paddr_t s, paddr_t *end)

{

    struct bootmodules *mi = &bootinfo.modules;

    paddr_t lowest = ~(paddr_t)0;

    int i;

    for ( i = 0; i < mi->nr_mods; i++ )

    {

        paddr_t mod_s = mi->module[i].start;

        paddr_t mod_e = mod_s + mi->module[i].size;

        if ( !mi->module[i].size )

            continue;

        if ( mod_s < s )

            continue;

        if ( mod_s > lowest )

            continue;

        if ( mod_s > *end )

            continue;

        lowest = mod_s;

        *end = min(*end, mod_e);

    }

    return lowest;

}

The job of next_module() function is excluding module exist RAM range between s and *end and finding empty space which can be heap space.

But Its function does not work if module range is bigger than s and *end range. 

(Case when module range is mod_s <= s and mod_e >= *end)

        if ( mod_s < s )

            continue;

Above condition passes the case and xen consider range s and *end is free space.

Is it expected result or mistake?

Thank you.

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