Messages in this thread | | | Date | Wed, 10 Jun 2015 00:46:11 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v5 5/5] block: loop: support DIO & AIO |
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> + int ret; > + > + /* nomerge for loop request queue */ > + WARN_ON(cmd->rq->bio != cmd->rq->biotail); > + > + bvec = __bvec_iter_bvec(bio->bi_io_vec, bio->bi_iter); > + iov_iter_bvec(&iter, ITER_BVEC | rw, bvec, > + bio_segments(bio), blk_rq_bytes(cmd->rq)); > + > + cmd->iocb.ki_pos = pos; > + cmd->iocb.ki_filp = file; > + cmd->iocb.ki_complete = lo_rw_aio_complete; > + cmd->iocb.ki_flags = IOCB_DIRECT; > + > + if (rw == WRITE) > + ret = file->f_op->write_iter(&cmd->iocb, &iter); > + else > + ret = file->f_op->read_iter(&cmd->iocb, &iter);
I think we really need a vfs_ wrapper here similar to what I did a while ago, e.g. vfs_iter_read/write_async.
> +static inline int lo_rw_simple(struct loop_device *lo, > + struct request *rq, loff_t pos, bool rw) > +{ > + struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); > + > + if (cmd->use_aio) > + return lo_rw_aio(lo, cmd, pos, rw); > + > + if (rw == WRITE) > + return lo_write_simple(lo, rq, pos); > + else > + return lo_read_simple(lo, rq, pos); > +}
And the io_submit style read/write also works for buffered I/O, so no need to keep lo_write_simple/lo_read_simple around.
> @@ -1569,7 +1634,8 @@ static void loop_handle_cmd(struct loop_cmd *cmd) > failed: > if (ret) > cmd->rq->errors = -EIO; > - blk_mq_complete_request(cmd->rq); > + if (!cmd->use_aio || ret) > + blk_mq_complete_request(cmd->rq);
If you don't complete the request here setting req->error doesn't make sense. I'd suggest to move the blk_mq_complete_request for everything but the trivial error case into the actual I/O handlers to clean this up a bit, too.
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