tree 557b303a058fc3effdfc15a5cc08867fb0ee6889
parent 2b69c83924396ad1eda36fdd267c9d2f360f5555
author NeilBrown <neilb@suse.de> 1243294877 +1000
committer NeilBrown <neilb@suse.de> 1243294877 +1000

md: bitmap: improve bitmap maintenance code.

The code for checking which bits in the bitmap can be cleared
has 2 problems:
 1/ it repeatedly takes and drops a spinlock, where it would make
    more sense to just hold on to it most of the time.
 2/ it doesn't make use of some opportunities to skip large sections
    of the bitmap

This patch fixes those.  It will only affect CPU consumption, not
correctness.

Signed-off-by: NeilBrown <neilb@suse.de>