[PATCH] bitmap: region cleanup

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: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 7d8ff97b3e92..d9ed27969855 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -46,6 +46,9 @@
  * bitmap_parse(ubuf, ulen, dst, nbits)         Parse bitmap dst from user buf
  * bitmap_scnlistprintf(buf, len, src, nbits)   Print bitmap src as list to buf
  * bitmap_parselist(buf, dst, nbits)            Parse bitmap dst from list
+ * bitmap_find_free_region(bitmap, bits, order) Find and allocate bit region
+ * bitmap_release_region(bitmap, pos, order)    Free specified bit region
+ * bitmap_allocate_region(bitmap, pos, order)   Allocate specified bit region
  */
 
 /*