[PATCH v3 0/6] restore nvme-rdma polling

[PATCH v3 0/6] restore nvme-rdma polling

[Sagi Grimberg]

Add an additional queue mapping for polling queues that will
host polling for latency critical I/O.

Allocate the poll queues with IB_POLL_DIRECT context. For nvmf connect
we introduce a new blk_execute_rq_polled to poll for the completion and
have nvmf_connect_io_queue use it for conneting polling queues.

Changes from v2:
- move blk_execute_rq_polled to nvme-core
- turn off REQ_HIPRI if polling is not supported (e.g. for stacking devices)
- omit nvme-cli patch - can be taken from v2
- removed blk_tag_to_qc_t and open-coded it in request_to_tag instead

Changes from v1:
- get rid of ib_change_cq_ctx
- poll for nvmf connect over poll queues

Christoph Hellwig (1):
  block: clear REQ_HIPRI if polling is not supported

Sagi Grimberg (5):
  block: make request_to_qc_t public
  nvme-core: optionally poll sync commands
  nvme-fabrics: allow nvmf_connect_io_queue to poll
  nvme-fabrics: allow user to pass in nr_poll_queues
  nvme-rdma: implement polling queue map

 block/blk-core.c            |  3 ++
 block/blk-mq.c              |  8 -----
 drivers/nvme/host/core.c    | 38 ++++++++++++++++++++----
 drivers/nvme/host/fabrics.c | 25 ++++++++++++----
 drivers/nvme/host/fabrics.h |  5 +++-
 drivers/nvme/host/fc.c      |  2 +-
 drivers/nvme/host/nvme.h    |  2 +-
 drivers/nvme/host/rdma.c    | 58 +++++++++++++++++++++++++++++++++----
 drivers/nvme/host/tcp.c     |  2 +-
 drivers/nvme/target/loop.c  |  2 +-
 include/linux/blk-mq.h      | 10 +++++++
 include/linux/blk_types.h   | 11 -------
 12 files changed, 125 insertions(+), 41 deletions(-)

-- 
2.17.1

[PATCH v3 0/6] restore nvme-rdma polling

[Sagi Grimberg]

Add an additional queue mapping for polling queues that will
host polling for latency critical I/O.

Allocate the poll queues with IB_POLL_DIRECT context. For nvmf connect
we introduce a new blk_execute_rq_polled to poll for the completion and
have nvmf_connect_io_queue use it for conneting polling queues.

Changes from v2:
- move blk_execute_rq_polled to nvme-core
- turn off REQ_HIPRI if polling is not supported (e.g. for stacking devices)
- omit nvme-cli patch - can be taken from v2
- removed blk_tag_to_qc_t and open-coded it in request_to_tag instead

Changes from v1:
- get rid of ib_change_cq_ctx
- poll for nvmf connect over poll queues

Christoph Hellwig (1):
  block: clear REQ_HIPRI if polling is not supported

Sagi Grimberg (5):
  block: make request_to_qc_t public
  nvme-core: optionally poll sync commands
  nvme-fabrics: allow nvmf_connect_io_queue to poll
  nvme-fabrics: allow user to pass in nr_poll_queues
  nvme-rdma: implement polling queue map

 block/blk-core.c            |  3 ++
 block/blk-mq.c              |  8 -----
 drivers/nvme/host/core.c    | 38 ++++++++++++++++++++----
 drivers/nvme/host/fabrics.c | 25 ++++++++++++----
 drivers/nvme/host/fabrics.h |  5 +++-
 drivers/nvme/host/fc.c      |  2 +-
 drivers/nvme/host/nvme.h    |  2 +-
 drivers/nvme/host/rdma.c    | 58 +++++++++++++++++++++++++++++++++----
 drivers/nvme/host/tcp.c     |  2 +-
 drivers/nvme/target/loop.c  |  2 +-
 include/linux/blk-mq.h      | 10 +++++++
 include/linux/blk_types.h   | 11 -------
 12 files changed, 125 insertions(+), 41 deletions(-)

-- 
2.17.1

[PATCH v3 1/6] block: clear REQ_HIPRI if polling is not supported

[Sagi Grimberg]

From: Christoph Hellwig <hch@lst.de>

This prevents a HIPRI bio from being submitted through a stacking
driver that does not support polling and thus won't poll for I/O
completion.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 block/blk-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index 268d2b8e9843..efa10789ddc0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -921,6 +921,9 @@ generic_make_request_checks(struct bio *bio)
 		}
 	}
 
+	if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+		bio->bi_opf &= ~REQ_HIPRI;
+
 	switch (bio_op(bio)) {
 	case REQ_OP_DISCARD:
 		if (!blk_queue_discard(q))
-- 
2.17.1

[PATCH v3 1/6] block: clear REQ_HIPRI if polling is not supported

[Sagi Grimberg]

From: Christoph Hellwig <hch@lst.de>

This prevents a HIPRI bio from being submitted through a stacking
driver that does not support polling and thus won't poll for I/O
completion.

Signed-off-by: Christoph Hellwig <hch at lst.de>
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 block/blk-core.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/block/blk-core.c b/block/blk-core.c
index 268d2b8e9843..efa10789ddc0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -921,6 +921,9 @@ generic_make_request_checks(struct bio *bio)
 		}
 	}
 
+	if (!test_bit(QUEUE_FLAG_POLL, &q->queue_flags))
+		bio->bi_opf &= ~REQ_HIPRI;
+
 	switch (bio_op(bio)) {
 	case REQ_OP_DISCARD:
 		if (!blk_queue_discard(q))
-- 
2.17.1

[PATCH v3 2/6] block: make request_to_qc_t public

[Sagi Grimberg]

block consumers will need it for polling requests that
are sent with blk_execute_rq_nowait. Also, get rid of
blk_tag_to_qc_t and open-code it instead.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 block/blk-mq.c            |  8 --------
 include/linux/blk-mq.h    | 10 ++++++++++
 include/linux/blk_types.h | 11 -----------
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index eff52c33e434..fb4a09b096d5 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1745,14 +1745,6 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
 	blk_account_io_start(rq, true);
 }
 
-static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
-{
-	if (rq->tag != -1)
-		return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false);
-
-	return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
-}
-
 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
 					    struct request *rq,
 					    blk_qc_t *cookie, bool last)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 57eda7b20243..2dd84feaf1ef 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -357,4 +357,14 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq)
 	for ((i) = 0; (i) < (hctx)->nr_ctx &&				\
 	     ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
 
+static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
+		struct request *rq)
+{
+	if (rq->tag != -1)
+		return rq->tag | (hctx->queue_num << BLK_QC_T_SHIFT);
+
+	return rq->internal_tag | (hctx->queue_num << BLK_QC_T_SHIFT) |
+			BLK_QC_T_INTERNAL;
+}
+
 #endif
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 46c005d601ac..ee1ce9058302 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -424,17 +424,6 @@ static inline bool blk_qc_t_valid(blk_qc_t cookie)
 	return cookie != BLK_QC_T_NONE;
 }
 
-static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
-				       bool internal)
-{
-	blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
-
-	if (internal)
-		ret |= BLK_QC_T_INTERNAL;
-
-	return ret;
-}
-
 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 {
 	return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
-- 
2.17.1

[PATCH v3 2/6] block: make request_to_qc_t public

[Sagi Grimberg]

block consumers will need it for polling requests that
are sent with blk_execute_rq_nowait. Also, get rid of
blk_tag_to_qc_t and open-code it instead.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 block/blk-mq.c            |  8 --------
 include/linux/blk-mq.h    | 10 ++++++++++
 include/linux/blk_types.h | 11 -----------
 3 files changed, 10 insertions(+), 19 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index eff52c33e434..fb4a09b096d5 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1745,14 +1745,6 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
 	blk_account_io_start(rq, true);
 }
 
-static blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx, struct request *rq)
-{
-	if (rq->tag != -1)
-		return blk_tag_to_qc_t(rq->tag, hctx->queue_num, false);
-
-	return blk_tag_to_qc_t(rq->internal_tag, hctx->queue_num, true);
-}
-
 static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
 					    struct request *rq,
 					    blk_qc_t *cookie, bool last)
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 57eda7b20243..2dd84feaf1ef 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -357,4 +357,14 @@ static inline void *blk_mq_rq_to_pdu(struct request *rq)
 	for ((i) = 0; (i) < (hctx)->nr_ctx &&				\
 	     ({ ctx = (hctx)->ctxs[(i)]; 1; }); (i)++)
 
+static inline blk_qc_t request_to_qc_t(struct blk_mq_hw_ctx *hctx,
+		struct request *rq)
+{
+	if (rq->tag != -1)
+		return rq->tag | (hctx->queue_num << BLK_QC_T_SHIFT);
+
+	return rq->internal_tag | (hctx->queue_num << BLK_QC_T_SHIFT) |
+			BLK_QC_T_INTERNAL;
+}
+
 #endif
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 46c005d601ac..ee1ce9058302 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -424,17 +424,6 @@ static inline bool blk_qc_t_valid(blk_qc_t cookie)
 	return cookie != BLK_QC_T_NONE;
 }
 
-static inline blk_qc_t blk_tag_to_qc_t(unsigned int tag, unsigned int queue_num,
-				       bool internal)
-{
-	blk_qc_t ret = tag | (queue_num << BLK_QC_T_SHIFT);
-
-	if (internal)
-		ret |= BLK_QC_T_INTERNAL;
-
-	return ret;
-}
-
 static inline unsigned int blk_qc_t_to_queue_num(blk_qc_t cookie)
 {
 	return (cookie & ~BLK_QC_T_INTERNAL) >> BLK_QC_T_SHIFT;
-- 
2.17.1

Re: [PATCH v3 2/6] block: make request_to_qc_t public

[Christoph Hellwig]

On Thu, Dec 13, 2018 at 01:34:06PM -0800, Sagi Grimberg wrote:
> block consumers will need it for polling requests that
> are sent with blk_execute_rq_nowait. Also, get rid of
> blk_tag_to_qc_t and open-code it instead.
> 
> Signed-off-by: Sagi Grimberg <sagi@grimberg.me>

Looks good,

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH v3 2/6] block: make request_to_qc_t public

[Christoph Hellwig]

On Thu, Dec 13, 2018@01:34:06PM -0800, Sagi Grimberg wrote:
> block consumers will need it for polling requests that
> are sent with blk_execute_rq_nowait. Also, get rid of
> blk_tag_to_qc_t and open-code it instead.
> 
> Signed-off-by: Sagi Grimberg <sagi at grimberg.me>

Looks good,

Reviewed-by: Christoph Hellwig <hch at lst.de>

Re: [PATCH v3 2/6] block: make request_to_qc_t public

[Jens Axboe]

On 12/13/18 2:34 PM, Sagi Grimberg wrote:
> block consumers will need it for polling requests that
> are sent with blk_execute_rq_nowait. Also, get rid of
> blk_tag_to_qc_t and open-code it instead.

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe

[PATCH v3 2/6] block: make request_to_qc_t public

[Jens Axboe]

On 12/13/18 2:34 PM, Sagi Grimberg wrote:
> block consumers will need it for polling requests that
> are sent with blk_execute_rq_nowait. Also, get rid of
> blk_tag_to_qc_t and open-code it instead.

Reviewed-by: Jens Axboe <axboe at kernel.dk>

-- 
Jens Axboe

[PATCH v3 3/6] nvme-core: optionally poll sync commands

[Sagi Grimberg]

Pass poll bool to indicate that we need it to poll. This prepares us for
polling support in nvmf since connect is an I/O that will be queued
and has to be polled in order to complete. If poll is passed,
we call nvme_execute_rq_polled which sends the requests and polls
for its completion.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/core.c    | 38 ++++++++++++++++++++++++++++++++-----
 drivers/nvme/host/fabrics.c | 10 +++++-----
 drivers/nvme/host/nvme.h    |  2 +-
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 136512e8ba58..08f2c92602f4 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -724,6 +724,31 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 }
 EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 
+static void nvme_end_sync_rq(struct request *rq, blk_status_t error)
+{
+	struct completion *waiting = rq->end_io_data;
+
+	rq->end_io_data = NULL;
+	complete(waiting);
+}
+
+static void nvme_execute_rq_polled(struct request_queue *q,
+		struct gendisk *bd_disk, struct request *rq, int at_head)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	WARN_ON_ONCE(!test_bit(QUEUE_FLAG_POLL, &q->queue_flags));
+
+	rq->cmd_flags |= REQ_HIPRI;
+	rq->end_io_data = &wait;
+	blk_execute_rq_nowait(q, bd_disk, rq, at_head, nvme_end_sync_rq);
+
+	while (!completion_done(&wait)) {
+		blk_poll(q, request_to_qc_t(rq->mq_hctx, rq), true);
+		cond_resched();
+	}
+}
+
 /*
  * Returns 0 on success.  If the result is negative, it's a Linux error code;
  * if the result is positive, it's an NVM Express status code
@@ -731,7 +756,7 @@ EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		union nvme_result *result, void *buffer, unsigned bufflen,
 		unsigned timeout, int qid, int at_head,
-		blk_mq_req_flags_t flags)
+		blk_mq_req_flags_t flags, bool poll)
 {
 	struct request *req;
 	int ret;
@@ -748,7 +773,10 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 			goto out;
 	}
 
-	blk_execute_rq(req->q, NULL, req, at_head);
+	if (poll)
+		nvme_execute_rq_polled(req->q, NULL, req, at_head);
+	else
+		blk_execute_rq(req->q, NULL, req, at_head);
 	if (result)
 		*result = nvme_req(req)->result;
 	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
@@ -765,7 +793,7 @@ int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void *buffer, unsigned bufflen)
 {
 	return __nvme_submit_sync_cmd(q, cmd, NULL, buffer, bufflen, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 }
 EXPORT_SYMBOL_GPL(nvme_submit_sync_cmd);
 
@@ -1084,7 +1112,7 @@ static int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword
 	c.features.dword11 = cpu_to_le32(dword11);
 
 	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res,
-			buffer, buflen, 0, NVME_QID_ANY, 0, 0);
+			buffer, buflen, 0, NVME_QID_ANY, 0, 0, false);
 	if (ret >= 0 && result)
 		*result = le32_to_cpu(res.u32);
 	return ret;
@@ -1727,7 +1755,7 @@ int nvme_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len,
 	cmd.common.cdw11 = cpu_to_le32(len);
 
 	return __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, buffer, len,
-				      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0);
+				      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0, false);
 }
 EXPORT_SYMBOL_GPL(nvme_sec_submit);
 #endif /* CONFIG_BLK_SED_OPAL */
diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 19ff0eae4582..d93a169f6403 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -159,7 +159,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
 	cmd.prop_get.offset = cpu_to_le32(off);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 
 	if (ret >= 0)
 		*val = le64_to_cpu(res.u64);
@@ -206,7 +206,7 @@ int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val)
 	cmd.prop_get.offset = cpu_to_le32(off);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 
 	if (ret >= 0)
 		*val = le64_to_cpu(res.u64);
@@ -252,7 +252,7 @@ int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
 	cmd.prop_set.value = cpu_to_le64(val);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 	if (unlikely(ret))
 		dev_err(ctrl->device,
 			"Property Set error: %d, offset %#x\n",
@@ -406,7 +406,7 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res,
 			data, sizeof(*data), 0, NVME_QID_ANY, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
@@ -468,7 +468,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
 
 	ret = __nvme_submit_sync_cmd(ctrl->connect_q, &cmd, &res,
 			data, sizeof(*data), 0, qid, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 39b52f4d9b24..2b36ac922596 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -447,7 +447,7 @@ int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		union nvme_result *result, void *buffer, unsigned bufflen,
 		unsigned timeout, int qid, int at_head,
-		blk_mq_req_flags_t flags);
+		blk_mq_req_flags_t flags, bool poll);
 int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count);
 void nvme_stop_keep_alive(struct nvme_ctrl *ctrl);
 int nvme_reset_ctrl(struct nvme_ctrl *ctrl);
-- 
2.17.1

[PATCH v3 3/6] nvme-core: optionally poll sync commands

[Sagi Grimberg]

Pass poll bool to indicate that we need it to poll. This prepares us for
polling support in nvmf since connect is an I/O that will be queued
and has to be polled in order to complete. If poll is passed,
we call nvme_execute_rq_polled which sends the requests and polls
for its completion.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/core.c    | 38 ++++++++++++++++++++++++++++++++-----
 drivers/nvme/host/fabrics.c | 10 +++++-----
 drivers/nvme/host/nvme.h    |  2 +-
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 136512e8ba58..08f2c92602f4 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -724,6 +724,31 @@ blk_status_t nvme_setup_cmd(struct nvme_ns *ns, struct request *req,
 }
 EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 
+static void nvme_end_sync_rq(struct request *rq, blk_status_t error)
+{
+	struct completion *waiting = rq->end_io_data;
+
+	rq->end_io_data = NULL;
+	complete(waiting);
+}
+
+static void nvme_execute_rq_polled(struct request_queue *q,
+		struct gendisk *bd_disk, struct request *rq, int at_head)
+{
+	DECLARE_COMPLETION_ONSTACK(wait);
+
+	WARN_ON_ONCE(!test_bit(QUEUE_FLAG_POLL, &q->queue_flags));
+
+	rq->cmd_flags |= REQ_HIPRI;
+	rq->end_io_data = &wait;
+	blk_execute_rq_nowait(q, bd_disk, rq, at_head, nvme_end_sync_rq);
+
+	while (!completion_done(&wait)) {
+		blk_poll(q, request_to_qc_t(rq->mq_hctx, rq), true);
+		cond_resched();
+	}
+}
+
 /*
  * Returns 0 on success.  If the result is negative, it's a Linux error code;
  * if the result is positive, it's an NVM Express status code
@@ -731,7 +756,7 @@ EXPORT_SYMBOL_GPL(nvme_setup_cmd);
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		union nvme_result *result, void *buffer, unsigned bufflen,
 		unsigned timeout, int qid, int at_head,
-		blk_mq_req_flags_t flags)
+		blk_mq_req_flags_t flags, bool poll)
 {
 	struct request *req;
 	int ret;
@@ -748,7 +773,10 @@ int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 			goto out;
 	}
 
-	blk_execute_rq(req->q, NULL, req, at_head);
+	if (poll)
+		nvme_execute_rq_polled(req->q, NULL, req, at_head);
+	else
+		blk_execute_rq(req->q, NULL, req, at_head);
 	if (result)
 		*result = nvme_req(req)->result;
 	if (nvme_req(req)->flags & NVME_REQ_CANCELLED)
@@ -765,7 +793,7 @@ int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		void *buffer, unsigned bufflen)
 {
 	return __nvme_submit_sync_cmd(q, cmd, NULL, buffer, bufflen, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 }
 EXPORT_SYMBOL_GPL(nvme_submit_sync_cmd);
 
@@ -1084,7 +1112,7 @@ static int nvme_set_features(struct nvme_ctrl *dev, unsigned fid, unsigned dword
 	c.features.dword11 = cpu_to_le32(dword11);
 
 	ret = __nvme_submit_sync_cmd(dev->admin_q, &c, &res,
-			buffer, buflen, 0, NVME_QID_ANY, 0, 0);
+			buffer, buflen, 0, NVME_QID_ANY, 0, 0, false);
 	if (ret >= 0 && result)
 		*result = le32_to_cpu(res.u32);
 	return ret;
@@ -1727,7 +1755,7 @@ int nvme_sec_submit(void *data, u16 spsp, u8 secp, void *buffer, size_t len,
 	cmd.common.cdw11 = cpu_to_le32(len);
 
 	return __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, buffer, len,
-				      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0);
+				      ADMIN_TIMEOUT, NVME_QID_ANY, 1, 0, false);
 }
 EXPORT_SYMBOL_GPL(nvme_sec_submit);
 #endif /* CONFIG_BLK_SED_OPAL */
diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 19ff0eae4582..d93a169f6403 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -159,7 +159,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val)
 	cmd.prop_get.offset = cpu_to_le32(off);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 
 	if (ret >= 0)
 		*val = le64_to_cpu(res.u64);
@@ -206,7 +206,7 @@ int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val)
 	cmd.prop_get.offset = cpu_to_le32(off);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 
 	if (ret >= 0)
 		*val = le64_to_cpu(res.u64);
@@ -252,7 +252,7 @@ int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val)
 	cmd.prop_set.value = cpu_to_le64(val);
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, NULL, NULL, 0, 0,
-			NVME_QID_ANY, 0, 0);
+			NVME_QID_ANY, 0, 0, false);
 	if (unlikely(ret))
 		dev_err(ctrl->device,
 			"Property Set error: %d, offset %#x\n",
@@ -406,7 +406,7 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl)
 
 	ret = __nvme_submit_sync_cmd(ctrl->admin_q, &cmd, &res,
 			data, sizeof(*data), 0, NVME_QID_ANY, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
@@ -468,7 +468,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
 
 	ret = __nvme_submit_sync_cmd(ctrl->connect_q, &cmd, &res,
 			data, sizeof(*data), 0, qid, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h
index 39b52f4d9b24..2b36ac922596 100644
--- a/drivers/nvme/host/nvme.h
+++ b/drivers/nvme/host/nvme.h
@@ -447,7 +447,7 @@ int nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 int __nvme_submit_sync_cmd(struct request_queue *q, struct nvme_command *cmd,
 		union nvme_result *result, void *buffer, unsigned bufflen,
 		unsigned timeout, int qid, int at_head,
-		blk_mq_req_flags_t flags);
+		blk_mq_req_flags_t flags, bool poll);
 int nvme_set_queue_count(struct nvme_ctrl *ctrl, int *count);
 void nvme_stop_keep_alive(struct nvme_ctrl *ctrl);
 int nvme_reset_ctrl(struct nvme_ctrl *ctrl);
-- 
2.17.1

Re: [PATCH v3 3/6] nvme-core: optionally poll sync commands

[Christoph Hellwig]

On Thu, Dec 13, 2018 at 01:34:07PM -0800, Sagi Grimberg wrote:
> Pass poll bool to indicate that we need it to poll. This prepares us for
> polling support in nvmf since connect is an I/O that will be queued
> and has to be polled in order to complete. If poll is passed,
> we call nvme_execute_rq_polled which sends the requests and polls
> for its completion.

Looks fine,

Reviewed-by: Christoph Hellwig <hch@lst.de>

[PATCH v3 3/6] nvme-core: optionally poll sync commands

[Christoph Hellwig]

On Thu, Dec 13, 2018@01:34:07PM -0800, Sagi Grimberg wrote:
> Pass poll bool to indicate that we need it to poll. This prepares us for
> polling support in nvmf since connect is an I/O that will be queued
> and has to be polled in order to complete. If poll is passed,
> we call nvme_execute_rq_polled which sends the requests and polls
> for its completion.

Looks fine,

Reviewed-by: Christoph Hellwig <hch at lst.de>

[PATCH v3 4/6] nvme-fabrics: allow nvmf_connect_io_queue to poll

[Sagi Grimberg]

Preparation for polling support for fabrics. Polling support
means that our completion queues are not generating any interrupts
which means we need to poll for the nvmf io queue connect as well.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed by Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/fabrics.c | 4 ++--
 drivers/nvme/host/fabrics.h | 2 +-
 drivers/nvme/host/fc.c      | 2 +-
 drivers/nvme/host/rdma.c    | 2 +-
 drivers/nvme/host/tcp.c     | 2 +-
 drivers/nvme/target/loop.c  | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index d93a169f6403..5ff14f46a8d9 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -441,7 +441,7 @@ EXPORT_SYMBOL_GPL(nvmf_connect_admin_queue);
  *	> 0: NVMe error status code
  *	< 0: Linux errno error code
  */
-int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
+int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid, bool poll)
 {
 	struct nvme_command cmd;
 	struct nvmf_connect_data *data;
@@ -468,7 +468,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
 
 	ret = __nvme_submit_sync_cmd(ctrl->connect_q, &cmd, &res,
 			data, sizeof(*data), 0, qid, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, poll);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index 81b8fd1c0c5d..cad70a9f976a 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -168,7 +168,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val);
 int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val);
 int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val);
 int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl);
-int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid);
+int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid, bool poll);
 int nvmf_register_transport(struct nvmf_transport_ops *ops);
 void nvmf_unregister_transport(struct nvmf_transport_ops *ops);
 void nvmf_free_options(struct nvmf_ctrl_options *opts);
diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index b79e41938513..89accc76d71c 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1975,7 +1975,7 @@ nvme_fc_connect_io_queues(struct nvme_fc_ctrl *ctrl, u16 qsize)
 					(qsize / 5));
 		if (ret)
 			break;
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, i, false);
 		if (ret)
 			break;
 
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index ed726da77b5b..b907ed43814f 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -598,7 +598,7 @@ static int nvme_rdma_start_queue(struct nvme_rdma_ctrl *ctrl, int idx)
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, false);
 	else
 		ret = nvmf_connect_admin_queue(&ctrl->ctrl);
 
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 51826479a41e..762a676403ef 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1393,7 +1393,7 @@ static int nvme_tcp_start_queue(struct nvme_ctrl *nctrl, int idx)
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(nctrl, idx);
+		ret = nvmf_connect_io_queue(nctrl, idx, false);
 	else
 		ret = nvmf_connect_admin_queue(nctrl);
 
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index 9908082b32c4..4aac1b4a8112 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -345,7 +345,7 @@ static int nvme_loop_connect_io_queues(struct nvme_loop_ctrl *ctrl)
 	int i, ret;
 
 	for (i = 1; i < ctrl->ctrl.queue_count; i++) {
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, i, false);
 		if (ret)
 			return ret;
 		set_bit(NVME_LOOP_Q_LIVE, &ctrl->queues[i].flags);
-- 
2.17.1

[PATCH v3 4/6] nvme-fabrics: allow nvmf_connect_io_queue to poll

[Sagi Grimberg]

Preparation for polling support for fabrics. Polling support
means that our completion queues are not generating any interrupts
which means we need to poll for the nvmf io queue connect as well.

Reviewed-by: Christoph Hellwig <hch at lst.de>
Reviewed by Steve Wise <swise at opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/fabrics.c | 4 ++--
 drivers/nvme/host/fabrics.h | 2 +-
 drivers/nvme/host/fc.c      | 2 +-
 drivers/nvme/host/rdma.c    | 2 +-
 drivers/nvme/host/tcp.c     | 2 +-
 drivers/nvme/target/loop.c  | 2 +-
 6 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index d93a169f6403..5ff14f46a8d9 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -441,7 +441,7 @@ EXPORT_SYMBOL_GPL(nvmf_connect_admin_queue);
  *	> 0: NVMe error status code
  *	< 0: Linux errno error code
  */
-int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
+int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid, bool poll)
 {
 	struct nvme_command cmd;
 	struct nvmf_connect_data *data;
@@ -468,7 +468,7 @@ int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid)
 
 	ret = __nvme_submit_sync_cmd(ctrl->connect_q, &cmd, &res,
 			data, sizeof(*data), 0, qid, 1,
-			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, false);
+			BLK_MQ_REQ_RESERVED | BLK_MQ_REQ_NOWAIT, poll);
 	if (ret) {
 		nvmf_log_connect_error(ctrl, ret, le32_to_cpu(res.u32),
 				       &cmd, data);
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index 81b8fd1c0c5d..cad70a9f976a 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -168,7 +168,7 @@ int nvmf_reg_read32(struct nvme_ctrl *ctrl, u32 off, u32 *val);
 int nvmf_reg_read64(struct nvme_ctrl *ctrl, u32 off, u64 *val);
 int nvmf_reg_write32(struct nvme_ctrl *ctrl, u32 off, u32 val);
 int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl);
-int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid);
+int nvmf_connect_io_queue(struct nvme_ctrl *ctrl, u16 qid, bool poll);
 int nvmf_register_transport(struct nvmf_transport_ops *ops);
 void nvmf_unregister_transport(struct nvmf_transport_ops *ops);
 void nvmf_free_options(struct nvmf_ctrl_options *opts);
diff --git a/drivers/nvme/host/fc.c b/drivers/nvme/host/fc.c
index b79e41938513..89accc76d71c 100644
--- a/drivers/nvme/host/fc.c
+++ b/drivers/nvme/host/fc.c
@@ -1975,7 +1975,7 @@ nvme_fc_connect_io_queues(struct nvme_fc_ctrl *ctrl, u16 qsize)
 					(qsize / 5));
 		if (ret)
 			break;
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, i, false);
 		if (ret)
 			break;
 
diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index ed726da77b5b..b907ed43814f 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -598,7 +598,7 @@ static int nvme_rdma_start_queue(struct nvme_rdma_ctrl *ctrl, int idx)
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, false);
 	else
 		ret = nvmf_connect_admin_queue(&ctrl->ctrl);
 
diff --git a/drivers/nvme/host/tcp.c b/drivers/nvme/host/tcp.c
index 51826479a41e..762a676403ef 100644
--- a/drivers/nvme/host/tcp.c
+++ b/drivers/nvme/host/tcp.c
@@ -1393,7 +1393,7 @@ static int nvme_tcp_start_queue(struct nvme_ctrl *nctrl, int idx)
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(nctrl, idx);
+		ret = nvmf_connect_io_queue(nctrl, idx, false);
 	else
 		ret = nvmf_connect_admin_queue(nctrl);
 
diff --git a/drivers/nvme/target/loop.c b/drivers/nvme/target/loop.c
index 9908082b32c4..4aac1b4a8112 100644
--- a/drivers/nvme/target/loop.c
+++ b/drivers/nvme/target/loop.c
@@ -345,7 +345,7 @@ static int nvme_loop_connect_io_queues(struct nvme_loop_ctrl *ctrl)
 	int i, ret;
 
 	for (i = 1; i < ctrl->ctrl.queue_count; i++) {
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, i);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, i, false);
 		if (ret)
 			return ret;
 		set_bit(NVME_LOOP_Q_LIVE, &ctrl->queues[i].flags);
-- 
2.17.1

[PATCH v3 5/6] nvme-fabrics: allow user to pass in nr_poll_queues

[Sagi Grimberg]

This argument will specify how many polling I/O queues
to connect when creating the controller. These I/O queues
will host I/O that is set with REQ_HIPRI.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/fabrics.c | 13 +++++++++++++
 drivers/nvme/host/fabrics.h |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 5ff14f46a8d9..b2ab213f43de 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -617,6 +617,7 @@ static const match_table_t opt_tokens = {
 	{ NVMF_OPT_HDR_DIGEST,		"hdr_digest"		},
 	{ NVMF_OPT_DATA_DIGEST,		"data_digest"		},
 	{ NVMF_OPT_NR_WRITE_QUEUES,	"nr_write_queues=%d"	},
+	{ NVMF_OPT_NR_POLL_QUEUES,	"nr_poll_queues=%d"	},
 	{ NVMF_OPT_ERR,			NULL			}
 };
 
@@ -850,6 +851,18 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			opts->nr_write_queues = token;
 			break;
+		case NVMF_OPT_NR_POLL_QUEUES:
+			if (match_int(args, &token)) {
+				ret = -EINVAL;
+				goto out;
+			}
+			if (token <= 0) {
+				pr_err("Invalid nr_poll_queues %d\n", token);
+				ret = -EINVAL;
+				goto out;
+			}
+			opts->nr_poll_queues = token;
+			break;
 		default:
 			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
 				p);
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index cad70a9f976a..478343b73e38 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -62,6 +62,7 @@ enum {
 	NVMF_OPT_HDR_DIGEST	= 1 << 15,
 	NVMF_OPT_DATA_DIGEST	= 1 << 16,
 	NVMF_OPT_NR_WRITE_QUEUES = 1 << 17,
+	NVMF_OPT_NR_POLL_QUEUES = 1 << 18,
 };
 
 /**
@@ -93,6 +94,7 @@ enum {
  * @hdr_digest: generate/verify header digest (TCP)
  * @data_digest: generate/verify data digest (TCP)
  * @nr_write_queues: number of queues for write I/O
+ * @nr_poll_queues: number of queues for polling I/O
  */
 struct nvmf_ctrl_options {
 	unsigned		mask;
@@ -113,6 +115,7 @@ struct nvmf_ctrl_options {
 	bool			hdr_digest;
 	bool			data_digest;
 	unsigned int		nr_write_queues;
+	unsigned int		nr_poll_queues;
 };
 
 /*
-- 
2.17.1

[PATCH v3 5/6] nvme-fabrics: allow user to pass in nr_poll_queues

[Sagi Grimberg]

This argument will specify how many polling I/O queues
to connect when creating the controller. These I/O queues
will host I/O that is set with REQ_HIPRI.

Reviewed-by: Christoph Hellwig <hch at lst.de>
Reviewed-by: Steve Wise <swise at opengridcomputing.com>
Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/fabrics.c | 13 +++++++++++++
 drivers/nvme/host/fabrics.h |  3 +++
 2 files changed, 16 insertions(+)

diff --git a/drivers/nvme/host/fabrics.c b/drivers/nvme/host/fabrics.c
index 5ff14f46a8d9..b2ab213f43de 100644
--- a/drivers/nvme/host/fabrics.c
+++ b/drivers/nvme/host/fabrics.c
@@ -617,6 +617,7 @@ static const match_table_t opt_tokens = {
 	{ NVMF_OPT_HDR_DIGEST,		"hdr_digest"		},
 	{ NVMF_OPT_DATA_DIGEST,		"data_digest"		},
 	{ NVMF_OPT_NR_WRITE_QUEUES,	"nr_write_queues=%d"	},
+	{ NVMF_OPT_NR_POLL_QUEUES,	"nr_poll_queues=%d"	},
 	{ NVMF_OPT_ERR,			NULL			}
 };
 
@@ -850,6 +851,18 @@ static int nvmf_parse_options(struct nvmf_ctrl_options *opts,
 			}
 			opts->nr_write_queues = token;
 			break;
+		case NVMF_OPT_NR_POLL_QUEUES:
+			if (match_int(args, &token)) {
+				ret = -EINVAL;
+				goto out;
+			}
+			if (token <= 0) {
+				pr_err("Invalid nr_poll_queues %d\n", token);
+				ret = -EINVAL;
+				goto out;
+			}
+			opts->nr_poll_queues = token;
+			break;
 		default:
 			pr_warn("unknown parameter or missing value '%s' in ctrl creation request\n",
 				p);
diff --git a/drivers/nvme/host/fabrics.h b/drivers/nvme/host/fabrics.h
index cad70a9f976a..478343b73e38 100644
--- a/drivers/nvme/host/fabrics.h
+++ b/drivers/nvme/host/fabrics.h
@@ -62,6 +62,7 @@ enum {
 	NVMF_OPT_HDR_DIGEST	= 1 << 15,
 	NVMF_OPT_DATA_DIGEST	= 1 << 16,
 	NVMF_OPT_NR_WRITE_QUEUES = 1 << 17,
+	NVMF_OPT_NR_POLL_QUEUES = 1 << 18,
 };
 
 /**
@@ -93,6 +94,7 @@ enum {
  * @hdr_digest: generate/verify header digest (TCP)
  * @data_digest: generate/verify data digest (TCP)
  * @nr_write_queues: number of queues for write I/O
+ * @nr_poll_queues: number of queues for polling I/O
  */
 struct nvmf_ctrl_options {
 	unsigned		mask;
@@ -113,6 +115,7 @@ struct nvmf_ctrl_options {
 	bool			hdr_digest;
 	bool			data_digest;
 	unsigned int		nr_write_queues;
+	unsigned int		nr_poll_queues;
 };
 
 /*
-- 
2.17.1

[PATCH v3 6/6] nvme-rdma: implement polling queue map

[Sagi Grimberg]

When passed with nr_poll_queues setup additional queues with cq polling
context IB_POLL_DIRECT (no interrupts) and make sure to set
QUEUE_FLAG_POLL on the connect_q. In addition add the third queue
mapping for polling queues.

nvmf connect on this queue is polled for like all other requests so make
nvmf_connect_io_queue poll for polling queues.

Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
---
 drivers/nvme/host/rdma.c | 58 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index b907ed43814f..80b3113b45fb 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -162,6 +162,13 @@ static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
 	return queue - queue->ctrl->queues;
 }
 
+static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)
+{
+	return nvme_rdma_queue_idx(queue) >
+		queue->ctrl->ctrl.opts->nr_io_queues +
+		queue->ctrl->ctrl.opts->nr_write_queues;
+}
+
 static inline size_t nvme_rdma_inline_data_size(struct nvme_rdma_queue *queue)
 {
 	return queue->cmnd_capsule_len - sizeof(struct nvme_command);
@@ -440,6 +447,7 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	const int send_wr_factor = 3;			/* MR, SEND, INV */
 	const int cq_factor = send_wr_factor + 1;	/* + RECV */
 	int comp_vector, idx = nvme_rdma_queue_idx(queue);
+	enum ib_poll_context poll_ctx;
 	int ret;
 
 	queue->device = nvme_rdma_find_get_device(queue->cm_id);
@@ -456,10 +464,16 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	 */
 	comp_vector = idx == 0 ? idx : idx - 1;
 
+	/* Polling queues need direct cq polling context */
+	if (nvme_rdma_poller_queue(queue))
+		poll_ctx = IB_POLL_DIRECT;
+	else
+		poll_ctx = IB_POLL_SOFTIRQ;
+
 	/* +1 for ib_stop_cq */
 	queue->ib_cq = ib_alloc_cq(ibdev, queue,
 				cq_factor * queue->queue_size + 1,
-				comp_vector, IB_POLL_SOFTIRQ);
+				comp_vector, poll_ctx);
 	if (IS_ERR(queue->ib_cq)) {
 		ret = PTR_ERR(queue->ib_cq);
 		goto out_put_dev;
@@ -595,15 +609,17 @@ static void nvme_rdma_stop_io_queues(struct nvme_rdma_ctrl *ctrl)
 
 static int nvme_rdma_start_queue(struct nvme_rdma_ctrl *ctrl, int idx)
 {
+	struct nvme_rdma_queue *queue = &ctrl->queues[idx];
+	bool poll = nvme_rdma_poller_queue(queue);
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, false);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, poll);
 	else
 		ret = nvmf_connect_admin_queue(&ctrl->ctrl);
 
 	if (!ret)
-		set_bit(NVME_RDMA_Q_LIVE, &ctrl->queues[idx].flags);
+		set_bit(NVME_RDMA_Q_LIVE, &queue->flags);
 	else
 		dev_info(ctrl->ctrl.device,
 			"failed to connect queue: %d ret=%d\n", idx, ret);
@@ -646,6 +662,7 @@ static int nvme_rdma_alloc_io_queues(struct nvme_rdma_ctrl *ctrl)
 				ibdev->num_comp_vectors);
 
 	nr_io_queues += min(opts->nr_write_queues, num_online_cpus());
+	nr_io_queues += min(opts->nr_poll_queues, num_online_cpus());
 
 	ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
 	if (ret)
@@ -716,7 +733,7 @@ static struct blk_mq_tag_set *nvme_rdma_alloc_tagset(struct nvme_ctrl *nctrl,
 		set->driver_data = ctrl;
 		set->nr_hw_queues = nctrl->queue_count - 1;
 		set->timeout = NVME_IO_TIMEOUT;
-		set->nr_maps = 2 /* default + read */;
+		set->nr_maps = HCTX_MAX_TYPES;
 	}
 
 	ret = blk_mq_alloc_tag_set(set);
@@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
 			ret = PTR_ERR(ctrl->ctrl.connect_q);
 			goto out_free_tag_set;
 		}
+
+		if (ctrl->ctrl.opts->nr_poll_queues)
+			blk_queue_flag_set(QUEUE_FLAG_POLL,
+				ctrl->ctrl.connect_q);
 	} else {
 		blk_mq_update_nr_hw_queues(&ctrl->tag_set,
 			ctrl->ctrl.queue_count - 1);
@@ -1742,6 +1763,14 @@ static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 	return BLK_STS_IOERR;
 }
 
+static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
+{
+	struct nvme_rdma_queue *queue = hctx->driver_data;
+	struct ib_cq *cq = queue->ib_cq;
+
+	return ib_process_cq_direct(cq, -1);
+}
+
 static void nvme_rdma_complete_rq(struct request *rq)
 {
 	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
@@ -1772,6 +1801,21 @@ static int nvme_rdma_map_queues(struct blk_mq_tag_set *set)
 			ctrl->device->dev, 0);
 	blk_mq_rdma_map_queues(&set->map[HCTX_TYPE_READ],
 			ctrl->device->dev, 0);
+
+	if (ctrl->ctrl.opts->nr_poll_queues) {
+		set->map[HCTX_TYPE_POLL].nr_queues =
+				ctrl->ctrl.opts->nr_poll_queues;
+		set->map[HCTX_TYPE_POLL].queue_offset =
+				ctrl->ctrl.opts->nr_io_queues;
+		if (ctrl->ctrl.opts->nr_write_queues)
+			set->map[HCTX_TYPE_POLL].queue_offset +=
+				ctrl->ctrl.opts->nr_write_queues;
+	} else {
+		set->map[HCTX_TYPE_POLL].nr_queues =
+				ctrl->ctrl.opts->nr_io_queues;
+		set->map[HCTX_TYPE_POLL].queue_offset = 0;
+	}
+	blk_mq_map_queues(&set->map[HCTX_TYPE_POLL]);
 	return 0;
 }
 
@@ -1783,6 +1827,7 @@ static const struct blk_mq_ops nvme_rdma_mq_ops = {
 	.init_hctx	= nvme_rdma_init_hctx,
 	.timeout	= nvme_rdma_timeout,
 	.map_queues	= nvme_rdma_map_queues,
+	.poll		= nvme_rdma_poll,
 };
 
 static const struct blk_mq_ops nvme_rdma_admin_mq_ops = {
@@ -1927,7 +1972,8 @@ static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
 	INIT_WORK(&ctrl->err_work, nvme_rdma_error_recovery_work);
 	INIT_WORK(&ctrl->ctrl.reset_work, nvme_rdma_reset_ctrl_work);
 
-	ctrl->ctrl.queue_count = opts->nr_io_queues + opts->nr_write_queues + 1;
+	ctrl->ctrl.queue_count = opts->nr_io_queues + opts->nr_write_queues +
+				opts->nr_poll_queues + 1;
 	ctrl->ctrl.sqsize = opts->queue_size - 1;
 	ctrl->ctrl.kato = opts->kato;
 
@@ -1979,7 +2025,7 @@ static struct nvmf_transport_ops nvme_rdma_transport = {
 	.required_opts	= NVMF_OPT_TRADDR,
 	.allowed_opts	= NVMF_OPT_TRSVCID | NVMF_OPT_RECONNECT_DELAY |
 			  NVMF_OPT_HOST_TRADDR | NVMF_OPT_CTRL_LOSS_TMO |
-			  NVMF_OPT_NR_WRITE_QUEUES,
+			  NVMF_OPT_NR_WRITE_QUEUES | NVMF_OPT_NR_POLL_QUEUES,
 	.create_ctrl	= nvme_rdma_create_ctrl,
 };
 
-- 
2.17.1

[PATCH v3 6/6] nvme-rdma: implement polling queue map

[Sagi Grimberg]

When passed with nr_poll_queues setup additional queues with cq polling
context IB_POLL_DIRECT (no interrupts) and make sure to set
QUEUE_FLAG_POLL on the connect_q. In addition add the third queue
mapping for polling queues.

nvmf connect on this queue is polled for like all other requests so make
nvmf_connect_io_queue poll for polling queues.

Signed-off-by: Sagi Grimberg <sagi at grimberg.me>
---
 drivers/nvme/host/rdma.c | 58 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 52 insertions(+), 6 deletions(-)

diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
index b907ed43814f..80b3113b45fb 100644
--- a/drivers/nvme/host/rdma.c
+++ b/drivers/nvme/host/rdma.c
@@ -162,6 +162,13 @@ static inline int nvme_rdma_queue_idx(struct nvme_rdma_queue *queue)
 	return queue - queue->ctrl->queues;
 }
 
+static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)
+{
+	return nvme_rdma_queue_idx(queue) >
+		queue->ctrl->ctrl.opts->nr_io_queues +
+		queue->ctrl->ctrl.opts->nr_write_queues;
+}
+
 static inline size_t nvme_rdma_inline_data_size(struct nvme_rdma_queue *queue)
 {
 	return queue->cmnd_capsule_len - sizeof(struct nvme_command);
@@ -440,6 +447,7 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	const int send_wr_factor = 3;			/* MR, SEND, INV */
 	const int cq_factor = send_wr_factor + 1;	/* + RECV */
 	int comp_vector, idx = nvme_rdma_queue_idx(queue);
+	enum ib_poll_context poll_ctx;
 	int ret;
 
 	queue->device = nvme_rdma_find_get_device(queue->cm_id);
@@ -456,10 +464,16 @@ static int nvme_rdma_create_queue_ib(struct nvme_rdma_queue *queue)
 	 */
 	comp_vector = idx == 0 ? idx : idx - 1;
 
+	/* Polling queues need direct cq polling context */
+	if (nvme_rdma_poller_queue(queue))
+		poll_ctx = IB_POLL_DIRECT;
+	else
+		poll_ctx = IB_POLL_SOFTIRQ;
+
 	/* +1 for ib_stop_cq */
 	queue->ib_cq = ib_alloc_cq(ibdev, queue,
 				cq_factor * queue->queue_size + 1,
-				comp_vector, IB_POLL_SOFTIRQ);
+				comp_vector, poll_ctx);
 	if (IS_ERR(queue->ib_cq)) {
 		ret = PTR_ERR(queue->ib_cq);
 		goto out_put_dev;
@@ -595,15 +609,17 @@ static void nvme_rdma_stop_io_queues(struct nvme_rdma_ctrl *ctrl)
 
 static int nvme_rdma_start_queue(struct nvme_rdma_ctrl *ctrl, int idx)
 {
+	struct nvme_rdma_queue *queue = &ctrl->queues[idx];
+	bool poll = nvme_rdma_poller_queue(queue);
 	int ret;
 
 	if (idx)
-		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, false);
+		ret = nvmf_connect_io_queue(&ctrl->ctrl, idx, poll);
 	else
 		ret = nvmf_connect_admin_queue(&ctrl->ctrl);
 
 	if (!ret)
-		set_bit(NVME_RDMA_Q_LIVE, &ctrl->queues[idx].flags);
+		set_bit(NVME_RDMA_Q_LIVE, &queue->flags);
 	else
 		dev_info(ctrl->ctrl.device,
 			"failed to connect queue: %d ret=%d\n", idx, ret);
@@ -646,6 +662,7 @@ static int nvme_rdma_alloc_io_queues(struct nvme_rdma_ctrl *ctrl)
 				ibdev->num_comp_vectors);
 
 	nr_io_queues += min(opts->nr_write_queues, num_online_cpus());
+	nr_io_queues += min(opts->nr_poll_queues, num_online_cpus());
 
 	ret = nvme_set_queue_count(&ctrl->ctrl, &nr_io_queues);
 	if (ret)
@@ -716,7 +733,7 @@ static struct blk_mq_tag_set *nvme_rdma_alloc_tagset(struct nvme_ctrl *nctrl,
 		set->driver_data = ctrl;
 		set->nr_hw_queues = nctrl->queue_count - 1;
 		set->timeout = NVME_IO_TIMEOUT;
-		set->nr_maps = 2 /* default + read */;
+		set->nr_maps = HCTX_MAX_TYPES;
 	}
 
 	ret = blk_mq_alloc_tag_set(set);
@@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
 			ret = PTR_ERR(ctrl->ctrl.connect_q);
 			goto out_free_tag_set;
 		}
+
+		if (ctrl->ctrl.opts->nr_poll_queues)
+			blk_queue_flag_set(QUEUE_FLAG_POLL,
+				ctrl->ctrl.connect_q);
 	} else {
 		blk_mq_update_nr_hw_queues(&ctrl->tag_set,
 			ctrl->ctrl.queue_count - 1);
@@ -1742,6 +1763,14 @@ static blk_status_t nvme_rdma_queue_rq(struct blk_mq_hw_ctx *hctx,
 	return BLK_STS_IOERR;
 }
 
+static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
+{
+	struct nvme_rdma_queue *queue = hctx->driver_data;
+	struct ib_cq *cq = queue->ib_cq;
+
+	return ib_process_cq_direct(cq, -1);
+}
+
 static void nvme_rdma_complete_rq(struct request *rq)
 {
 	struct nvme_rdma_request *req = blk_mq_rq_to_pdu(rq);
@@ -1772,6 +1801,21 @@ static int nvme_rdma_map_queues(struct blk_mq_tag_set *set)
 			ctrl->device->dev, 0);
 	blk_mq_rdma_map_queues(&set->map[HCTX_TYPE_READ],
 			ctrl->device->dev, 0);
+
+	if (ctrl->ctrl.opts->nr_poll_queues) {
+		set->map[HCTX_TYPE_POLL].nr_queues =
+				ctrl->ctrl.opts->nr_poll_queues;
+		set->map[HCTX_TYPE_POLL].queue_offset =
+				ctrl->ctrl.opts->nr_io_queues;
+		if (ctrl->ctrl.opts->nr_write_queues)
+			set->map[HCTX_TYPE_POLL].queue_offset +=
+				ctrl->ctrl.opts->nr_write_queues;
+	} else {
+		set->map[HCTX_TYPE_POLL].nr_queues =
+				ctrl->ctrl.opts->nr_io_queues;
+		set->map[HCTX_TYPE_POLL].queue_offset = 0;
+	}
+	blk_mq_map_queues(&set->map[HCTX_TYPE_POLL]);
 	return 0;
 }
 
@@ -1783,6 +1827,7 @@ static const struct blk_mq_ops nvme_rdma_mq_ops = {
 	.init_hctx	= nvme_rdma_init_hctx,
 	.timeout	= nvme_rdma_timeout,
 	.map_queues	= nvme_rdma_map_queues,
+	.poll		= nvme_rdma_poll,
 };
 
 static const struct blk_mq_ops nvme_rdma_admin_mq_ops = {
@@ -1927,7 +1972,8 @@ static struct nvme_ctrl *nvme_rdma_create_ctrl(struct device *dev,
 	INIT_WORK(&ctrl->err_work, nvme_rdma_error_recovery_work);
 	INIT_WORK(&ctrl->ctrl.reset_work, nvme_rdma_reset_ctrl_work);
 
-	ctrl->ctrl.queue_count = opts->nr_io_queues + opts->nr_write_queues + 1;
+	ctrl->ctrl.queue_count = opts->nr_io_queues + opts->nr_write_queues +
+				opts->nr_poll_queues + 1;
 	ctrl->ctrl.sqsize = opts->queue_size - 1;
 	ctrl->ctrl.kato = opts->kato;
 
@@ -1979,7 +2025,7 @@ static struct nvmf_transport_ops nvme_rdma_transport = {
 	.required_opts	= NVMF_OPT_TRADDR,
 	.allowed_opts	= NVMF_OPT_TRSVCID | NVMF_OPT_RECONNECT_DELAY |
 			  NVMF_OPT_HOST_TRADDR | NVMF_OPT_CTRL_LOSS_TMO |
-			  NVMF_OPT_NR_WRITE_QUEUES,
+			  NVMF_OPT_NR_WRITE_QUEUES | NVMF_OPT_NR_POLL_QUEUES,
 	.create_ctrl	= nvme_rdma_create_ctrl,
 };
 
-- 
2.17.1

Re: [PATCH v3 6/6] nvme-rdma: implement polling queue map

[Christoph Hellwig]

> +static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)

Can we please make this poll_queue?  or at least polled_queue?
poller sounds odd..

> -		set->nr_maps = 2 /* default + read */;
> +		set->nr_maps = HCTX_MAX_TYPES;
>  	}
>  
>  	ret = blk_mq_alloc_tag_set(set);
> @@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
>  			ret = PTR_ERR(ctrl->ctrl.connect_q);
>  			goto out_free_tag_set;
>  		}
> +
> +		if (ctrl->ctrl.opts->nr_poll_queues)
> +			blk_queue_flag_set(QUEUE_FLAG_POLL,
> +				ctrl->ctrl.connect_q);

The block core is supposed to detect we can poll based on nr_maps > 2,
and then set QUEUE_FLAG_POLL automatically.  Although I got the details
wrong for PCI as well, but I just sent a fix..
> +static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
> +{
> +	struct nvme_rdma_queue *queue = hctx->driver_data;
> +	struct ib_cq *cq = queue->ib_cq;
> +
> +	return ib_process_cq_direct(cq, -1);

I think we can skip the cq local variable here.

Otherwise this looks really nice and simple, thanks for looking into it!

Do you have any performance number, especially with Jens' ringbuffer
code?

[PATCH v3 6/6] nvme-rdma: implement polling queue map

[Christoph Hellwig]

> +static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)

Can we please make this poll_queue?  or at least polled_queue?
poller sounds odd..

> -		set->nr_maps = 2 /* default + read */;
> +		set->nr_maps = HCTX_MAX_TYPES;
>  	}
>  
>  	ret = blk_mq_alloc_tag_set(set);
> @@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
>  			ret = PTR_ERR(ctrl->ctrl.connect_q);
>  			goto out_free_tag_set;
>  		}
> +
> +		if (ctrl->ctrl.opts->nr_poll_queues)
> +			blk_queue_flag_set(QUEUE_FLAG_POLL,
> +				ctrl->ctrl.connect_q);

The block core is supposed to detect we can poll based on nr_maps > 2,
and then set QUEUE_FLAG_POLL automatically.  Although I got the details
wrong for PCI as well, but I just sent a fix..
> +static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
> +{
> +	struct nvme_rdma_queue *queue = hctx->driver_data;
> +	struct ib_cq *cq = queue->ib_cq;
> +
> +	return ib_process_cq_direct(cq, -1);

I think we can skip the cq local variable here.

Otherwise this looks really nice and simple, thanks for looking into it!

Do you have any performance number, especially with Jens' ringbuffer
code?

Re: [PATCH v3 6/6] nvme-rdma: implement polling queue map

[Sagi Grimberg]

>> +static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)
> 
> Can we please make this poll_queue?  or at least polled_queue?
> poller sounds odd..

Changed to nvme_rdma_poll_queue..

> 
>> -		set->nr_maps = 2 /* default + read */;
>> +		set->nr_maps = HCTX_MAX_TYPES;
>>   	}
>>   
>>   	ret = blk_mq_alloc_tag_set(set);
>> @@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
>>   			ret = PTR_ERR(ctrl->ctrl.connect_q);
>>   			goto out_free_tag_set;
>>   		}
>> +
>> +		if (ctrl->ctrl.opts->nr_poll_queues)
>> +			blk_queue_flag_set(QUEUE_FLAG_POLL,
>> +				ctrl->ctrl.connect_q);
> 
> The block core is supposed to detect we can poll based on nr_maps > 2,
> and then set QUEUE_FLAG_POLL automatically.  Although I got the details
> wrong for PCI as well, but I just sent a fix..

I'll lose that, but I didn't understand what you got wrong for pci?
(didn't understand the fix either)

>> +static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
>> +{
>> +	struct nvme_rdma_queue *queue = hctx->driver_data;
>> +	struct ib_cq *cq = queue->ib_cq;
>> +
>> +	return ib_process_cq_direct(cq, -1);
> 
> I think we can skip the cq local variable here.

Lost..

> Otherwise this looks really nice and simple, thanks for looking into it!
> 
> Do you have any performance number, especially with Jens' ringbuffer
> code?

Well, I can get from my local vm on my laptop on top of soft-roce 7K
iops :) (compared tp 5.5K without polling, but not something to
conclude from)

I don't have any numbers to show for right now...

As I said in the cover letter, we want a way to tell ib_poll_cq_direct
to not count send completions (where we end our sqe), right now we are
probably screwing up poll_success stat...

[PATCH v3 6/6] nvme-rdma: implement polling queue map

[Sagi Grimberg]

>> +static bool nvme_rdma_poller_queue(struct nvme_rdma_queue *queue)
> 
> Can we please make this poll_queue?  or at least polled_queue?
> poller sounds odd..

Changed to nvme_rdma_poll_queue..

> 
>> -		set->nr_maps = 2 /* default + read */;
>> +		set->nr_maps = HCTX_MAX_TYPES;
>>   	}
>>   
>>   	ret = blk_mq_alloc_tag_set(set);
>> @@ -864,6 +881,10 @@ static int nvme_rdma_configure_io_queues(struct nvme_rdma_ctrl *ctrl, bool new)
>>   			ret = PTR_ERR(ctrl->ctrl.connect_q);
>>   			goto out_free_tag_set;
>>   		}
>> +
>> +		if (ctrl->ctrl.opts->nr_poll_queues)
>> +			blk_queue_flag_set(QUEUE_FLAG_POLL,
>> +				ctrl->ctrl.connect_q);
> 
> The block core is supposed to detect we can poll based on nr_maps > 2,
> and then set QUEUE_FLAG_POLL automatically.  Although I got the details
> wrong for PCI as well, but I just sent a fix..

I'll lose that, but I didn't understand what you got wrong for pci?
(didn't understand the fix either)

>> +static int nvme_rdma_poll(struct blk_mq_hw_ctx *hctx)
>> +{
>> +	struct nvme_rdma_queue *queue = hctx->driver_data;
>> +	struct ib_cq *cq = queue->ib_cq;
>> +
>> +	return ib_process_cq_direct(cq, -1);
> 
> I think we can skip the cq local variable here.

Lost..

> Otherwise this looks really nice and simple, thanks for looking into it!
> 
> Do you have any performance number, especially with Jens' ringbuffer
> code?

Well, I can get from my local vm on my laptop on top of soft-roce 7K
iops :) (compared tp 5.5K without polling, but not something to
conclude from)

I don't have any numbers to show for right now...

As I said in the cover letter, we want a way to tell ib_poll_cq_direct
to not count send completions (where we end our sqe), right now we are
probably screwing up poll_success stat...