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    Subject[PATCH 11 of 11] mmap sems
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    # HG changeset patch
    # User Andrea Arcangeli <andrea@qumranet.com>
    # Date 1210115798 -7200
    # Node ID eb924315351f6b056428e35c983ad28040420fea
    # Parent 5b2eb7d28a4517daf91b08b4dcfbb58fd2b42d0b
    mmap sems

    This patch adds a lock ordering rule to avoid a potential deadlock when
    multiple mmap_sems need to be locked.

    Signed-off-by: Dean Nelson <dcn@sgi.com>
    Signed-off-by: Andrea Arcangeli <andrea@qumranet.com>

    diff --git a/mm/filemap.c b/mm/filemap.c
    --- a/mm/filemap.c
    +++ b/mm/filemap.c
    @@ -79,6 +79,9 @@ generic_file_direct_IO(int rw, struct ki
    *
    * ->i_mutex (generic_file_buffered_write)
    * ->mmap_sem (fault_in_pages_readable->do_page_fault)
    + *
    + * When taking multiple mmap_sems, one should lock the lowest-addressed
    + * one first proceeding on up to the highest-addressed one.
    *
    * ->i_mutex
    * ->i_alloc_sem (various)

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      Last update: 2008-05-07 16:45    [W:0.027 / U:32.632 seconds]
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