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    Subject[PATCH 06/24] lmb: Add find_lmb_area()
    Date
    It will try find area according with size/align in specified range (start, end).

    Need use it find correct buffer for new lmb.reserved.region.

    also make it more easy for x86 to use lmb.
    x86 early_res is using find/reserve pattern instead of alloc.

    find_lmb_area() will hohor goal

    When we need temperary buff for range array etc for range work, if We are using
    lmb_alloc(), We will need to add some post fix code for buffer that is used
    by range array, because it is in the lmb.reserved already.

    Signed-off-by: Yinghai Lu <yinghai@kernel.org>
    ---
    include/linux/lmb.h | 4 ++
    mm/lmb.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++
    2 files changed, 85 insertions(+), 0 deletions(-)

    diff --git a/include/linux/lmb.h b/include/linux/lmb.h
    index e14ea8d..05234bd 100644
    --- a/include/linux/lmb.h
    +++ b/include/linux/lmb.h
    @@ -83,6 +83,10 @@ lmb_end_pfn(struct lmb_region *type, unsigned long region_nr)
    lmb_size_pages(type, region_nr);
    }

    +u64 __find_lmb_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
    + u64 size, u64 align);
    +u64 find_lmb_area(u64 start, u64 end, u64 size, u64 align);
    +
    #include <asm/lmb.h>

    #endif /* __KERNEL__ */
    diff --git a/mm/lmb.c b/mm/lmb.c
    index 65b62dc..d5d5dc4 100644
    --- a/mm/lmb.c
    +++ b/mm/lmb.c
    @@ -11,9 +11,13 @@
    */

    #include <linux/kernel.h>
    +#include <linux/types.h>
    #include <linux/init.h>
    #include <linux/bitops.h>
    #include <linux/lmb.h>
    +#include <linux/bootmem.h>
    +#include <linux/mm.h>
    +#include <linux/range.h>

    #define LMB_ALLOC_ANYWHERE 0

    @@ -546,3 +550,80 @@ int lmb_find(struct lmb_property *res)
    }
    return -1;
    }
    +
    +static int __init find_overlapped_early(u64 start, u64 end)
    +{
    + int i;
    + struct lmb_property *r;
    +
    + for (i = 0; i < lmb.reserved.cnt && lmb.reserved.region[i].size; i++) {
    + r = &lmb.reserved.region[i];
    + if (end > r->base && start < (r->base + r->size))
    + break;
    + }
    +
    + return i;
    +}
    +
    +/* Check for already reserved areas */
    +static inline bool __init bad_addr(u64 *addrp, u64 size, u64 align)
    +{
    + int i;
    + u64 addr = *addrp;
    + bool changed = false;
    + struct lmb_property *r;
    +again:
    + i = find_overlapped_early(addr, addr + size);
    + r = &lmb.reserved.region[i];
    + if (i < lmb.reserved.cnt && r->size) {
    + *addrp = addr = round_up(r->base + r->size, align);
    + changed = true;
    + goto again;
    + }
    + return changed;
    +}
    +
    +u64 __init __find_lmb_area(u64 ei_start, u64 ei_last, u64 start, u64 end,
    + u64 size, u64 align)
    +{
    + u64 addr, last;
    +
    + addr = round_up(ei_start, align);
    + if (addr < start)
    + addr = round_up(start, align);
    + if (addr >= ei_last)
    + goto out;
    + while (bad_addr(&addr, size, align) && addr+size <= ei_last)
    + ;
    + last = addr + size;
    + if (last > ei_last)
    + goto out;
    + if (last > end)
    + goto out;
    +
    + return addr;
    +
    +out:
    + return -1ULL;
    +}
    +
    +/*
    + * Find a free area with specified alignment in a specific range.
    + */
    +u64 __init find_lmb_area(u64 start, u64 end, u64 size, u64 align)
    +{
    + int i;
    +
    + for (i = 0; i < lmb.memory.cnt; i++) {
    + u64 ei_start = lmb.memory.region[i].base;
    + u64 ei_last = ei_start + lmb.memory.region[i].size;
    + u64 addr;
    +
    + addr = __find_lmb_area(ei_start, ei_last, start, end,
    + size, align);
    +
    + if (addr != -1ULL)
    + return addr;
    + }
    + return -1ULL;
    +}
    --
    1.6.4.2


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