• Paul Jackson's avatar
    [PATCH] bitmap: region cleanup · 87e24802
    Paul Jackson authored
    Paul Mundt <lethal@linux-sh.org> says:
    
    This patch set implements a number of patches to clean up and restructure the
    bitmap region code, in addition to extending the interface to support
    multiword spanning allocations.
    
    The current implementation (before this patch set) is limited by only being
    able to allocate pages <= BITS_PER_LONG, as noted by the strategically
    positioned BUG_ON() at lib/bitmap.c:752:
    
            /* We don't do regions of pages > BITS_PER_LONG.  The
    	 * algorithm would be a simple look for multiple zeros in the
    	 * array, but there's no driver today that needs this.  If you
    	 * trip this BUG(), you get to code it... */
            BUG_ON(pages > BITS_PER_LONG);
    
    As I seem to have been the first person to trigger this, the result ends up
    being the following patch set with the help of Paul Jackson.
    
    The final patch in the series eliminates quite a bit of code duplication, so
    the bitmap code size ends up being smaller than the current implementation as
    an added bonus.
    
    After these are applied, it should already be possible to do multiword
    allocations with dma_alloc_coherent() out of ranges established by
    dma_declare_coherent_memory() on x86 without having to change any of the code,
    and the SH store queue API will follow up on this as the other user that needs
    support for this.
    
    This patch:
    
    Some code cleanup on the lib/bitmap.c bitmap_*_region() routines:
    
     * spacing
     * variable names
     * comments
    
    Has no change to code function.
    Signed-off-by: default avatarPaul Mundt <lethal@linux-sh.org>
    Signed-off-by: default avatarPaul Jackson <pj@sgi.com>
    Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
    87e24802
bitmap.c 21.9 KB