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[05/27] blk-iocost: clamp inuse and skip noops in __propagate_weights()

Message ID 20200901185257.645114-6-tj@kernel.org (mailing list archive)
State New, archived
Headers show
Series [01/27] blk-iocost: ioc_pd_free() shouldn't assume irq disabled | expand

Commit Message

Tejun Heo Sept. 1, 2020, 6:52 p.m. UTC 
__propagate_weights() currently expects the callers to clamp inuse within
[1, active], which is needlessly fragile. The inuse adjustment logic is
going to be revamped, in preparation, let's make __propagate_weights() clamp
inuse on entry.

Also, make it avoid weight updates altogether if neither active or inuse is
changed.

Signed-off-by: Tejun Heo <tj@kernel.org>
---
 block/blk-iocost.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index 78e6919153d8..8dfe73dde2a8 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -897,7 +897,10 @@  static void __propagate_weights(struct ioc_gq *iocg, u32 active, u32 inuse)
 
 	lockdep_assert_held(&ioc->lock);
 
-	inuse = min(active, inuse);
+	inuse = clamp_t(u32, inuse, 1, active);
+
+	if (active == iocg->active && inuse == iocg->inuse)
+		return;
 
 	for (lvl = iocg->level - 1; lvl >= 0; lvl--) {
 		struct ioc_gq *parent = iocg->ancestors[lvl];