Re: [PATCH v3 3/5] nvme-fabrics: avoid double request completion for nvmf_fail_nonready_command
From: Hannes Reinecke <hare@suse.de>
Date: 2021-01-21 09:00:18
Also in:
linux-nvme
On 1/21/21 8:03 AM, Chao Leng wrote:
When reconnect, the request may be completed with NVME_SC_HOST_PATH_ERROR in nvmf_fail_nonready_command. The state of request will be changed to MQ_RQ_IN_FLIGHT before call nvme_complete_rq. If free the request asynchronously such as in nvme_submit_user_cmd, in extreme scenario the request may be completed again in tear down process. nvmf_fail_nonready_command do not need calling blk_mq_start_request before complete the request. nvmf_fail_nonready_command should set the state of request to MQ_RQ_COMPLETE before complete the request.
So what you are saying is that there is a race condition between blk_mq_start_request() and nvme_complete_request()
quoted hunk ↗ jump to hunk
Signed-off-by: Chao Leng <redacted> --- drivers/nvme/host/fabrics.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c index 72ac00173500..874e4320e214 100644 --- a/drivers/nvme/host/fabrics.c +++ b/drivers/nvme/host/fabrics.c@@ -553,9 +553,7 @@ blk_status_t nvmf_fail_nonready_command(struct nvme_ctrl *ctrl, !blk_noretry_request(rq) && !(rq->cmd_flags & REQ_NVME_MPATH)) return BLK_STS_RESOURCE; - nvme_req(rq)->status = NVME_SC_HOST_PATH_ERROR; - blk_mq_start_request(rq); - nvme_complete_rq(rq); + nvme_complete_failed_req(rq); return BLK_STS_OK; } EXPORT_SYMBOL_GPL(nvmf_fail_nonready_command);I'd rather have 'nvme_complete_failed_req()' accept the status as
argument, like nvme_complete_failed_request(rq, NVME_SC_HOST_PATH_ERROR) that way it's obvious what is happening, and the status isn't hidden in the function. Cheers, Hannes -- Dr. Hannes Reinecke Kernel Storage Architect hare@suse.de +49 911 74053 688 SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 36809 (AG Nürnberg), Geschäftsführer: Felix Imendörffer