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author | Paolo Valente <paolo.valente@linaro.org> | 2019-01-29 14:06:34 +0300 |
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committer | Jens Axboe <axboe@kernel.dk> | 2019-01-31 22:50:24 +0300 |
commit | 9dee8b3b057e1da26f85f1842f2aaf3bb200fb94 (patch) | |
tree | 909db0541b6ce1e5368ea986cde0483cdeddd32f /.get_maintainer.ignore | |
parent | d87447d84fe194b0e4f5413b5344dc82cc100711 (diff) | |
download | linux-9dee8b3b057e1da26f85f1842f2aaf3bb200fb94.tar.xz |
block, bfq: fix queue removal from weights tree
bfq maintains an ordered list, through a red-black tree, of unique
weights of active bfq_queues. This list is used to detect whether there
are active queues with differentiated weights. The weight of a queue is
removed from the list when both the following two conditions become
true:
(1) the bfq_queue is flagged as inactive
(2) the has no in-flight request any longer;
Unfortunately, in the rare cases where condition (2) becomes true before
condition (1), the removal fails, because the function to remove the
weight of the queue (bfq_weights_tree_remove) is rightly invoked in the
path that deactivates the bfq_queue, but mistakenly invoked *before* the
function that actually performs the deactivation (bfq_deactivate_bfqq).
This commits moves the invocation of bfq_weights_tree_remove for
condition (1) to after bfq_deactivate_bfqq. As a consequence of this
move, it is necessary to add a further reference to the queue when the
weight of a queue is added, because the queue might otherwise be freed
before bfq_weights_tree_remove is invoked. This commit adds this
reference and makes all related modifications.
Signed-off-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to '.get_maintainer.ignore')
0 files changed, 0 insertions, 0 deletions