Messages in this thread | | | Subject | Re: [PATCH] block: put the reference of the io scheduler module after switching back | From | Yu Kuai <> | Date | Tue, 11 Oct 2022 20:54:13 +0800 |
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Hi!
在 2022/10/11 18:21, Jinlong Chen 写道: > We got a reference of the io scheduler module in > blk_mq_elv_switch_none to prevent the module from > being removed. We need to put that reference back > once we are done.
However, if blk_mq_elv_switch_none() failed due to OOM, and module reference is not acquired, blk_mq_elv_switch_back() will still be called. This seems not to be the right fix.
Thanks, Kuai > > Signed-off-by: Jinlong Chen <chenjinlong2016@outlook.com> > --- > block/blk-mq.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index 8070b6c10e8d..8dfe3bf3e599 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -4595,6 +4595,13 @@ static void blk_mq_elv_switch_back(struct list_head *head, > > mutex_lock(&q->sysfs_lock); > elevator_switch(q, t); > + /** > + * We got a reference of the io scheduler module in > + * blk_mq_elv_switch_none to prevent the module from > + * being removed. We need to put that reference back > + * once we are done. > + */ > + module_put(t->elevator_owner); > mutex_unlock(&q->sysfs_lock); > } > >
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