Author: huhai <huhai@xxxxxxxxxx>
Date: Fri May 18 17:09:56 2018 +0800
blk-mq: make sure that correct hctx->dispatch_from is set
When the number of hardware queues is changed, the drivers will call
blk_mq_update_nr_hw_queues() to remap hardware queues, and then
the ctx mapped on hctx will also change, but the current code forgets to
make sure that correct hctx->dispatch_from is set, and hctx->dispatch_from
may point to a ctx that does not belong to the current hctx.
Signed-off-by: huhai <huhai@xxxxxxxxxx>
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 2545081..55d8a3d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2214,6 +2214,8 @@ static void blk_mq_map_swqueue(struct request_queue *q)
hctx->tags = set->tags[i];
WARN_ON(!hctx->tags);
+ hctx->dispatch_from = NULL;
+
/*
* Set the map size to the number of mapped software queues.
* This is more accurate and more efficient than looping
