From mboxrd@z Thu Jan 1 00:00:00 1970 From: keith.busch@intel.com (Keith Busch) Date: Tue, 27 Nov 2018 08:37:10 -0700 Subject: [PATCH] nvme: Implement Enhanced Command Retry Message-ID: <20181127153710.6328-1-keith.busch@intel.com> A controller may have an internal state that is not able to successfully process commands for a short duration. In such states, an immediate command requeue is expected to fail. The driver may exceed its max retry count, which permanently ends the command in failure when the same command would succeed after waiting for the controller to be ready. NVMe ratified TP 4033 provides a delay hint in the completion status code for failed commands. Implement the retry delay based on the command completion status and the controller's requested delay. Note that requeued commands are handled per request_queue, not per individual request. If multiple commands fail, the controller should consistently report the desired delay time for retryable commands in all CQEs, otherwise the requeue list may be kicked too soon. Signed-off-by: Keith Busch --- drivers/nvme/host/core.c | 37 ++++++++++++++++++++++++++++++++++++- drivers/nvme/host/nvme.h | 1 + include/linux/nvme.h | 17 ++++++++++++++++- 3 files changed, 53 insertions(+), 2 deletions(-) diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index c418b7a347e0..7397cb48db70 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -261,8 +261,16 @@ void nvme_complete_rq(struct request *req) } if (!blk_queue_dying(req->q)) { + unsigned long delay = 0; + struct nvme_ns *ns = req->q->queuedata; + u16 crd = (nvme_req(req)->status & NVME_SC_CRD) >> 11; + + if (crd && ns) + delay = ns->ctrl->crdt[crd - 1] * 100; + nvme_req(req)->retries++; - blk_mq_requeue_request(req, true); + blk_mq_requeue_request(req, false); + blk_mq_delay_kick_requeue_list(req->q, delay); return; } } @@ -1883,6 +1891,25 @@ static int nvme_configure_timestamp(struct nvme_ctrl *ctrl) return ret; } +static int nvme_configure_acre(struct nvme_ctrl *ctrl) +{ + struct nvme_feat_host_behavior *host; + int ret; + + if (!ctrl->crdt[0]) + return 0; + + host = kzalloc(sizeof(*host), GFP_KERNEL); + if (!host) + return 0; + + host->acre = NVME_ENABLE_ACRE; + ret = nvme_set_features(ctrl, NVME_FEAT_HOST_BEHAVIOR, 0, + host, sizeof(*host), NULL); + kfree(host); + return ret; +} + static int nvme_configure_apst(struct nvme_ctrl *ctrl) { /* @@ -2404,6 +2431,10 @@ int nvme_init_identify(struct nvme_ctrl *ctrl) ctrl->quirks &= ~NVME_QUIRK_NO_DEEPEST_PS; } + ctrl->crdt[0] = le16_to_cpu(id->crdt1); + ctrl->crdt[1] = le16_to_cpu(id->crdt2); + ctrl->crdt[2] = le16_to_cpu(id->crdt3); + ctrl->oacs = le16_to_cpu(id->oacs); ctrl->oncs = le16_to_cpup(&id->oncs); ctrl->oaes = le32_to_cpu(id->oaes); @@ -2504,6 +2535,10 @@ int nvme_init_identify(struct nvme_ctrl *ctrl) if (ret < 0) return ret; + ret = nvme_configure_acre(ctrl); + if (ret < 0) + return ret; + ctrl->identified = true; return 0; diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 27663ce3044e..51063dbf08bf 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -181,6 +181,7 @@ struct nvme_ctrl { u32 page_size; u32 max_hw_sectors; u32 max_segments; + u16 crdt[3]; u16 oncs; u16 oacs; u16 nssa; diff --git a/include/linux/nvme.h b/include/linux/nvme.h index c03973c215ad..88812cb15be0 100644 --- a/include/linux/nvme.h +++ b/include/linux/nvme.h @@ -223,7 +223,11 @@ struct nvme_id_ctrl { __le32 rtd3e; __le32 oaes; __le32 ctratt; - __u8 rsvd100[156]; + __u8 rsvd100[28]; + __le16 crdt1; + __le16 crdt2; + __le16 crdt3; + __u8 rsvd134[122]; __le16 oacs; __u8 acl; __u8 aerl; @@ -756,6 +760,15 @@ enum { NVME_HOST_MEM_RETURN = (1 << 1), }; +struct nvme_feat_host_behavior { + __u8 acre; + __u8 resv1[511]; +}; + +enum { + NVME_ENABLE_ACRE = 1, +}; + /* Admin commands */ enum nvme_admin_opcode { @@ -810,6 +823,7 @@ enum { NVME_FEAT_RRL = 0x12, NVME_FEAT_PLM_CONFIG = 0x13, NVME_FEAT_PLM_WINDOW = 0x14, + NVME_FEAT_HOST_BEHAVIOR = 0x16, NVME_FEAT_SW_PROGRESS = 0x80, NVME_FEAT_HOST_ID = 0x81, NVME_FEAT_RESV_MASK = 0x82, @@ -1265,6 +1279,7 @@ enum { NVME_SC_ANA_TRANSITION = 0x303, NVME_SC_HOST_PATH_ERROR = 0x370, + NVME_SC_CRD = 0x1800, NVME_SC_DNR = 0x4000, }; -- 2.14.4