tree f764ae05d916c21bfd06a271b900bfbc9f4316ff
parent 5cb8850c9c4a7605f74f5c9c7ecadd0b02e87a25
author Shlomo Pongratz <shlomop@mellanox.com> 1391704397 +0200
committer Jens Axboe <axboe@fb.com> 1391806567 -0700

block/null_blk: Fix completion processing from LIFO to FIFO

The completion queue is implemented using lockless list.

The llist_add is adds the events to the list head which is a push operation.
The processing of the completion elements is done by disconnecting all the
pushed elements and iterating over the disconnected list. The problem is
that the processing is done in reverse order w.r.t order of the insertion
i.e. LIFO processing. By reversing the disconnected list which is done in
linear time the desired FIFO processing is achieved.

Signed-off-by: Shlomo Pongratz <shlomop@mellanox.com>
Signed-off-by: Jens Axboe <axboe@fb.com>