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    Subjectkmap_atomic in 2.6.20.x
    Hello

    I am running into some problems with kmap_atomic in my driver.
    My driver copies some pages coming from
    user space to "kernel space kmalloc'ed memory".
    I had this code running from 2.6.5 to 2.6.17 without any problems.
    I have upgraded to 2.6.20.xx and this code fails to kmap_atomic.
    I am running a uni processor 2 GRAM machine, 32bit.

    Basically this is code does:

    get_user_pages(page,...)

    kmap_atomic(page,KM_USER0);
    .. copy and stuff
    kunmap_atomic(page,KM_USER0)

    I have also tried KM_USER1 and KM_SKB_SUNRPC_DATA.
    I crash in arch/i386/highmem.c line 42:
    ...
    if (!pte_none(*(kmap_pte-idx)))
    BUG();
    ..

    To the best of my understanding ( from "see : understand the linux
    kernel" page 310 ) , a different kernel component holds this window. A
    fact which is quite strange in the case of KM_SKB_SUNRPC_DATA. I have
    nothing that uses it.

    1. Why kmap_atomic does not return NULL ?
    2. Why am I failing only in high memory mappings ?

    --
    Raz
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