block: kill swap_io_context()
It blindly copies everything in the io_context, including the lock. That doesn't work so well for either lock ordering or lockdep. There seems zero point in swapping io contexts on a request to request merge, so the best point of action is to just remove it. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
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@ -1268,22 +1268,8 @@ static void as_merged_requests(struct request_queue *q, struct request *req,
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*/
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if (!list_empty(&req->queuelist) && !list_empty(&next->queuelist)) {
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if (time_before(rq_fifo_time(next), rq_fifo_time(req))) {
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struct io_context *rioc = RQ_IOC(req);
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struct io_context *nioc = RQ_IOC(next);
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list_move(&req->queuelist, &next->queuelist);
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rq_set_fifo_time(req, rq_fifo_time(next));
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/*
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* Don't copy here but swap, because when anext is
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* removed below, it must contain the unused context
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*/
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if (rioc != nioc) {
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double_spin_lock(&rioc->lock, &nioc->lock,
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rioc < nioc);
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swap_io_context(&rioc, &nioc);
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double_spin_unlock(&rioc->lock, &nioc->lock,
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rioc < nioc);
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}
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}
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}
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@ -176,15 +176,6 @@ void copy_io_context(struct io_context **pdst, struct io_context **psrc)
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}
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EXPORT_SYMBOL(copy_io_context);
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void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
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{
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struct io_context *temp;
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temp = *ioc1;
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*ioc1 = *ioc2;
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*ioc2 = temp;
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}
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EXPORT_SYMBOL(swap_io_context);
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int __init blk_ioc_init(void)
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{
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iocontext_cachep = kmem_cache_create("blkdev_ioc",
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@ -39,7 +39,6 @@ void exit_io_context(void);
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struct io_context *get_io_context(gfp_t gfp_flags, int node);
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struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
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void copy_io_context(struct io_context **pdst, struct io_context **psrc);
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void swap_io_context(struct io_context **ioc1, struct io_context **ioc2);
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struct request;
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typedef void (rq_end_io_fn)(struct request *, int);
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