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nvme: refactor command completion
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Lift all the code to decide the dispostition of a completed command
from nvme_complete_rq and nvme_failover_req into a new helper, which
returns an emum of the potential actions.  nvme_complete_rq then
just switches on those and calls the proper helper for the action.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Christoph Hellwig authored and Jens Axboe committed Aug 21, 2020
1 parent 2eb81a3 commit 5ddaabe
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Showing 3 changed files with 89 additions and 64 deletions.
75 changes: 48 additions & 27 deletions drivers/nvme/host/core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -241,17 +241,6 @@ static blk_status_t nvme_error_status(u16 status)
}
}

static inline bool nvme_req_needs_retry(struct request *req)
{
if (blk_noretry_request(req))
return false;
if (nvme_req(req)->status & NVME_SC_DNR)
return false;
if (nvme_req(req)->retries >= nvme_max_retries)
return false;
return true;
}

static void nvme_retry_req(struct request *req)
{
struct nvme_ns *ns = req->q->queuedata;
Expand All @@ -268,34 +257,66 @@ static void nvme_retry_req(struct request *req)
blk_mq_delay_kick_requeue_list(req->q, delay);
}

void nvme_complete_rq(struct request *req)
enum nvme_disposition {
COMPLETE,
RETRY,
FAILOVER,
};

static inline enum nvme_disposition nvme_decide_disposition(struct request *req)
{
blk_status_t status = nvme_error_status(nvme_req(req)->status);
if (likely(nvme_req(req)->status == 0))
return COMPLETE;

trace_nvme_complete_rq(req);
if (blk_noretry_request(req) ||
(nvme_req(req)->status & NVME_SC_DNR) ||
nvme_req(req)->retries >= nvme_max_retries)
return COMPLETE;

nvme_cleanup_cmd(req);
if (req->cmd_flags & REQ_NVME_MPATH) {
if (nvme_is_path_error(nvme_req(req)->status))
return FAILOVER;
}

if (nvme_req(req)->ctrl->kas)
nvme_req(req)->ctrl->comp_seen = true;
if (blk_queue_dying(req->q))
return COMPLETE;

if (unlikely(status != BLK_STS_OK && nvme_req_needs_retry(req))) {
if ((req->cmd_flags & REQ_NVME_MPATH) && nvme_failover_req(req))
return;
return RETRY;
}

if (!blk_queue_dying(req->q)) {
nvme_retry_req(req);
return;
}
} else if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
req_op(req) == REQ_OP_ZONE_APPEND) {
static inline void nvme_end_req(struct request *req)
{
blk_status_t status = nvme_error_status(nvme_req(req)->status);

if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
req_op(req) == REQ_OP_ZONE_APPEND)
req->__sector = nvme_lba_to_sect(req->q->queuedata,
le64_to_cpu(nvme_req(req)->result.u64));
}

nvme_trace_bio_complete(req, status);
blk_mq_end_request(req, status);
}

void nvme_complete_rq(struct request *req)
{
trace_nvme_complete_rq(req);
nvme_cleanup_cmd(req);

if (nvme_req(req)->ctrl->kas)
nvme_req(req)->ctrl->comp_seen = true;

switch (nvme_decide_disposition(req)) {
case COMPLETE:
nvme_end_req(req);
return;
case RETRY:
nvme_retry_req(req);
return;
case FAILOVER:
nvme_failover_req(req);
return;
}
}
EXPORT_SYMBOL_GPL(nvme_complete_rq);

bool nvme_cancel_request(struct request *req, void *data, bool reserved)
Expand Down
47 changes: 13 additions & 34 deletions drivers/nvme/host/multipath.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -65,51 +65,30 @@ void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
}
}

bool nvme_failover_req(struct request *req)
void nvme_failover_req(struct request *req)
{
struct nvme_ns *ns = req->q->queuedata;
u16 status = nvme_req(req)->status;
u16 status = nvme_req(req)->status & 0x7ff;
unsigned long flags;

switch (status & 0x7ff) {
case NVME_SC_ANA_TRANSITION:
case NVME_SC_ANA_INACCESSIBLE:
case NVME_SC_ANA_PERSISTENT_LOSS:
/*
* If we got back an ANA error we know the controller is alive,
* but not ready to serve this namespaces. The spec suggests
* we should update our general state here, but due to the fact
* that the admin and I/O queues are not serialized that is
* fundamentally racy. So instead just clear the current path,
* mark the the path as pending and kick of a re-read of the ANA
* log page ASAP.
*/
nvme_mpath_clear_current_path(ns);
if (ns->ctrl->ana_log_buf) {
set_bit(NVME_NS_ANA_PENDING, &ns->flags);
queue_work(nvme_wq, &ns->ctrl->ana_work);
}
break;
case NVME_SC_HOST_PATH_ERROR:
case NVME_SC_HOST_ABORTED_CMD:
/*
* Temporary transport disruption in talking to the controller.
* Try to send on a new path.
*/
nvme_mpath_clear_current_path(ns);
break;
default:
/* This was a non-ANA error so follow the normal error path. */
return false;
nvme_mpath_clear_current_path(ns);

/*
* If we got back an ANA error, we know the controller is alive but not
* ready to serve this namespace. Kick of a re-read of the ANA
* information page, and just try any other available path for now.
*/
if (nvme_is_ana_error(status) && ns->ctrl->ana_log_buf) {
set_bit(NVME_NS_ANA_PENDING, &ns->flags);
queue_work(nvme_wq, &ns->ctrl->ana_work);
}

spin_lock_irqsave(&ns->head->requeue_lock, flags);
blk_steal_bios(&ns->head->requeue_list, req);
spin_unlock_irqrestore(&ns->head->requeue_lock, flags);
blk_mq_end_request(req, 0);

blk_mq_end_request(req, 0);
kblockd_schedule_work(&ns->head->requeue_work);
return true;
}

void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
Expand Down
31 changes: 28 additions & 3 deletions drivers/nvme/host/nvme.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -523,6 +523,32 @@ static inline u32 nvme_bytes_to_numd(size_t len)
return (len >> 2) - 1;
}

static inline bool nvme_is_ana_error(u16 status)
{
switch (status & 0x7ff) {
case NVME_SC_ANA_TRANSITION:
case NVME_SC_ANA_INACCESSIBLE:
case NVME_SC_ANA_PERSISTENT_LOSS:
return true;
default:
return false;
}
}

static inline bool nvme_is_path_error(u16 status)
{
switch (status & 0x7ff) {
case NVME_SC_HOST_PATH_ERROR:
case NVME_SC_HOST_ABORTED_CMD:
case NVME_SC_ANA_TRANSITION:
case NVME_SC_ANA_INACCESSIBLE:
case NVME_SC_ANA_PERSISTENT_LOSS:
return true;
default:
return false;
}
}

/*
* Fill in the status and result information from the CQE, and then figure out
* if blk-mq will need to use IPI magic to complete the request, and if yes do
Expand Down Expand Up @@ -635,7 +661,7 @@ void nvme_mpath_wait_freeze(struct nvme_subsystem *subsys);
void nvme_mpath_start_freeze(struct nvme_subsystem *subsys);
void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
struct nvme_ctrl *ctrl, int *flags);
bool nvme_failover_req(struct request *req);
void nvme_failover_req(struct request *req);
void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl);
int nvme_mpath_alloc_disk(struct nvme_ctrl *ctrl,struct nvme_ns_head *head);
void nvme_mpath_add_disk(struct nvme_ns *ns, struct nvme_id_ns *id);
Expand Down Expand Up @@ -694,9 +720,8 @@ static inline void nvme_set_disk_name(char *disk_name, struct nvme_ns *ns,
sprintf(disk_name, "nvme%dn%d", ctrl->instance, ns->head->instance);
}

static inline bool nvme_failover_req(struct request *req)
static inline void nvme_failover_req(struct request *req)
{
return false;
}
static inline void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
{
Expand Down

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