Provided by: kernel-doc-2.4.27_2.4.27-12_all bug


       ll_rw_block - level access to block devices


       void ll_rw_block (int rw, int nr, struct buffer_head * *bhs);


       rw           whether to READ or WRITE or maybe READA (readahead)

       nr           number of struct buffer_heads in the array

       bhs          array of pointers to struct buffer_head


       ll_rw_block  takes  an  array  of  pointers to struct buffer_heads, and
       requests an I/O operation on them, either a READ or a WRITE.  The third
       READA option is described in the documentation for generic_make_request
       which ll_rw_block calls.

       This  function  provides   extra   functionality   that   is   not   in
       generic_make_request that is relevant to buffers in the buffer cache or
       page cache.  In particular it drops any buffer that  it  cannot  get  a
       lock  on  (with  the  BH_Lock state bit), any buffer that appears to be
       clean when doing a write request, and any buffer that appears to be up-
       to-date  when  doing  read  request.  Further it marks as clean buffers
       that are processed for writing (the buffer cache wont assume that  they
       are actually clean until the buffer gets unlocked).

       ll_rw_block  sets  b_end_io to simple completion handler that marks the
       buffer up-to-date (if approriate), unlocks the  buffer  and  wakes  any
       waiters.   As  client  that needs a more interesting completion routine
       should call submit_bh (or generic_make_request) directly.


       All of the buffers must be for the same device, and must also be