From f4829a9b7a61e159367350008a608b062c4f6840 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sun, 27 Sep 2015 21:01:50 +0200 Subject: blk-mq: fix racy updates of rq->errors blk_mq_complete_request may be a no-op if the request has already been completed by others means (e.g. a timeout or cancellation), but currently drivers have to set rq->errors before calling blk_mq_complete_request, which might leave us with the wrong error value. Add an error parameter to blk_mq_complete_request so that we can defer setting rq->errors until we known we won the race to complete the request. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Jens Axboe --- drivers/block/loop.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) (limited to 'drivers/block/loop.c') diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f9889b6bc02c..674f800a3b57 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -1486,17 +1486,16 @@ static void loop_handle_cmd(struct loop_cmd *cmd) { const bool write = cmd->rq->cmd_flags & REQ_WRITE; struct loop_device *lo = cmd->rq->q->queuedata; - int ret = -EIO; + int ret = 0; - if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) + if (write && (lo->lo_flags & LO_FLAGS_READ_ONLY)) { + ret = -EIO; goto failed; + } ret = do_req_filebacked(lo, cmd->rq); - failed: - if (ret) - cmd->rq->errors = -EIO; - blk_mq_complete_request(cmd->rq); + blk_mq_complete_request(cmd->rq, ret ? -EIO : 0); } static void loop_queue_write_work(struct work_struct *work) -- cgit v1.2.3