From fe2cb2905c3dc872158e7ce30df05d72c3989645 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 20 Apr 2017 16:03:02 +0200 Subject: [PATCH] loop: zero-fill bio on the submitting cpu In thruth I've just audited which blk-mq drivers don't currently have a complete callback, but I think this change is at least borderline useful. Signed-off-by: Christoph Hellwig Reviewed-by: Ming Lei Signed-off-by: Jens Axboe --- drivers/block/loop.c | 30 ++++++++++++++---------------- drivers/block/loop.h | 1 + 2 files changed, 15 insertions(+), 16 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 3081d83..86351b3 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -445,32 +445,27 @@ static int lo_req_flush(struct loop_device *lo, struct request *rq) return ret; } -static inline void handle_partial_read(struct loop_cmd *cmd, long bytes) +static void lo_complete_rq(struct request *rq) { - if (bytes < 0 || op_is_write(req_op(cmd->rq))) - return; + struct loop_cmd *cmd = blk_mq_rq_to_pdu(rq); - if (unlikely(bytes < blk_rq_bytes(cmd->rq))) { + if (unlikely(req_op(cmd->rq) == REQ_OP_READ && cmd->use_aio && + cmd->ret >= 0 && cmd->ret < blk_rq_bytes(cmd->rq))) { struct bio *bio = cmd->rq->bio; - bio_advance(bio, bytes); + bio_advance(bio, cmd->ret); zero_fill_bio(bio); } + + blk_mq_end_request(rq, cmd->ret < 0 ? -EIO : 0); } static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) { struct loop_cmd *cmd = container_of(iocb, struct loop_cmd, iocb); - struct request *rq = cmd->rq; - - handle_partial_read(cmd, ret); - if (ret > 0) - ret = 0; - else if (ret < 0) - ret = -EIO; - - blk_mq_complete_request(rq, ret); + cmd->ret = ret; + blk_mq_complete_request(cmd->rq, 0); } static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, @@ -1688,8 +1683,10 @@ static void loop_handle_cmd(struct loop_cmd *cmd) ret = do_req_filebacked(lo, cmd->rq); failed: /* complete non-aio request */ - if (!cmd->use_aio || ret) - blk_mq_complete_request(cmd->rq, ret ? -EIO : 0); + if (!cmd->use_aio || ret) { + cmd->ret = ret ? -EIO : 0; + blk_mq_complete_request(cmd->rq, 0); + } } static void loop_queue_work(struct kthread_work *work) @@ -1715,6 +1712,7 @@ static int loop_init_request(void *data, struct request *rq, static const struct blk_mq_ops loop_mq_ops = { .queue_rq = loop_queue_rq, .init_request = loop_init_request, + .complete = lo_complete_rq, }; static int loop_add(struct loop_device **l, int i) diff --git a/drivers/block/loop.h b/drivers/block/loop.h index fb2237c..fecd3f9 100644 --- a/drivers/block/loop.h +++ b/drivers/block/loop.h @@ -70,6 +70,7 @@ struct loop_cmd { struct request *rq; struct list_head list; bool use_aio; /* use AIO interface to handle I/O */ + long ret; struct kiocb iocb; }; -- 2.7.4