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From: Max Gurtovoy <maxg@mellanox.com>
To: jgg@mellanox.com, linux-nvme@lists.infradead.org,
	sagi@grimberg.me, hch@lst.de, kbusch@kernel.org,
	Chaitanya.Kulkarni@wdc.com
Cc: krishna2@chelsio.com, Max Gurtovoy <maxg@mellanox.com>,
	bharat@chelsio.com, nirranjan@chelsio.com, bvanassche@acm.org
Subject: [PATCH V2 1/3] nvmet: Add get_mdts op for controllers
Date: Thu,  5 Mar 2020 11:55:28 +0200	[thread overview]
Message-ID: <20200305095530.132858-1-maxg@mellanox.com> (raw)

Some transports, such as RDMA, would like to set the Maximum Data
Transfer Size (MDTS) according to device/port/ctrl characteristics.
This will enable the transport to set the optimal MDTS according to
controller needs and device capabilities. Add a new nvmet transport
op that is called during ctrl identification. This will not effect
transports that don't implement this option. The return value of the new
op is according to the NVMe spec definition for MDTS.

Signed-off-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Israel Rukshin <israelr@mellanox.com>
---

changes from V1:
 - renamed set_mdts to get_mdts (Bart)
 - added const for ctrl argument (Bart)
 - updated commit message to explain return value of the new op (Bart)

---
 drivers/nvme/target/admin-cmd.c | 8 ++++++--
 drivers/nvme/target/nvmet.h     | 1 +
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index c0aa9c3..b9ec489 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -369,8 +369,12 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
 	/* we support multiple ports, multiples hosts and ANA: */
 	id->cmic = (1 << 0) | (1 << 1) | (1 << 3);
 
-	/* no limit on data transfer sizes for now */
-	id->mdts = 0;
+	/* Limit MDTS according to transport capability */
+	if (ctrl->ops->get_mdts)
+		id->mdts = ctrl->ops->get_mdts(ctrl);
+	else
+		id->mdts = 0;
+
 	id->cntlid = cpu_to_le16(ctrl->cntlid);
 	id->ver = cpu_to_le32(ctrl->subsys->ver);
 
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 42ba2dd..421dff3 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -289,6 +289,7 @@ struct nvmet_fabrics_ops {
 			struct nvmet_port *port, char *traddr);
 	u16 (*install_queue)(struct nvmet_sq *nvme_sq);
 	void (*discovery_chg)(struct nvmet_port *port);
+	u8 (*get_mdts)(const struct nvmet_ctrl *ctrl);
 };
 
 #define NVMET_MAX_INLINE_BIOVEC	8
-- 
1.8.3.1


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             reply	other threads:[~2020-03-05 11:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-05  9:55 Max Gurtovoy [this message]
2020-03-05  9:55 ` [PATCH V2 2/3] nvmet-rdma: Implement get_mdts controller op Max Gurtovoy
2020-03-05 20:44   ` Sagi Grimberg
2020-03-05 23:01     ` Max Gurtovoy
2020-03-05  9:55 ` [PATCH V2 3/3] nvmet-rdma: allocate RW ctxs according to mdts Max Gurtovoy
2020-03-05 20:49   ` Sagi Grimberg
2020-03-05 22:59     ` Max Gurtovoy
2020-03-06  1:19       ` Sagi Grimberg
2020-03-05 20:40 ` [PATCH V2 1/3] nvmet: Add get_mdts op for controllers Sagi Grimberg

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