Commit a70b81bd authored by Hannes Reinecke's avatar Hannes Reinecke Committed by Christoph Hellwig
Browse files

nvme: sanitize KATO setting 



According to the NVMe base spec the KATO commands should be sent
at half of the KATO interval, to properly account for round-trip
times.
As we now will only ever send one KATO command per connection we
can easily use the recommended values.
This also fixes a potential issue where the request timeout for
the KATO command does not match the value in the connect command,
which might be causing spurious connection drops from the target.

Signed-off-by: default avatarHannes Reinecke <hare@suse.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
parent 8f864c59

drivers/nvme/host/core.c

+14 −3
Original line number Diff line number Diff line
@@ -1109,6 +1109,17 @@ void nvme_execute_passthru_rq(struct request *rq) 
}

EXPORT_SYMBOL_NS_GPL(nvme_execute_passthru_rq, NVME_TARGET_PASSTHRU);



/*

 * Recommended frequency for KATO commands per NVMe 1.4 section 7.12.1:

 * 

 *   The host should send Keep Alive commands at half of the Keep Alive Timeout

 *   accounting for transport roundtrip times [..].

 */

static void nvme_queue_keep_alive_work(struct nvme_ctrl *ctrl)

{

	queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ / 2);

}



static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status)

{

	struct nvme_ctrl *ctrl = rq->end_io_data;
@@ -1131,7 +1142,7 @@ static void nvme_keep_alive_end_io(struct request *rq, blk_status_t status) 
		startka = true;

	spin_unlock_irqrestore(&ctrl->lock, flags);

	if (startka)

		queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);

		nvme_queue_keep_alive_work(ctrl);

}



static int nvme_keep_alive(struct nvme_ctrl *ctrl)
@@ -1161,7 +1172,7 @@ static void nvme_keep_alive_work(struct work_struct *work) 
		dev_dbg(ctrl->device,

			"reschedule traffic based keep-alive timer\n");

		ctrl->comp_seen = false;

		queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);

		nvme_queue_keep_alive_work(ctrl);

		return;

	}
@@ -1178,7 +1189,7 @@ static void nvme_start_keep_alive(struct nvme_ctrl *ctrl) 
	if (unlikely(ctrl->kato == 0))

		return;



	queue_delayed_work(nvme_wq, &ctrl->ka_work, ctrl->kato * HZ);

	nvme_queue_keep_alive_work(ctrl);

}



void nvme_stop_keep_alive(struct nvme_ctrl *ctrl)

drivers/nvme/host/fabrics.c

+1 −3
Original line number Diff line number Diff line
@@ -379,10 +379,8 @@ int nvmf_connect_admin_queue(struct nvme_ctrl *ctrl) 


	/*

	 * Set keep-alive timeout in seconds granularity (ms * 1000)

	 * and add a grace period for controller kato enforcement

	 */

	cmd.connect.kato = ctrl->kato ?

		cpu_to_le32((ctrl->kato + NVME_KATO_GRACE) * 1000) : 0;

	cmd.connect.kato = cpu_to_le32(ctrl->kato * 1000);



	if (ctrl->opts->disable_sqflow)

		cmd.connect.cattr |= NVME_CONNECT_DISABLE_SQFLOW;

drivers/nvme/host/nvme.h

+0 −1
Original line number Diff line number Diff line
@@ -27,7 +27,6 @@ extern unsigned int admin_timeout; 
#define NVME_ADMIN_TIMEOUT	(admin_timeout * HZ)



#define NVME_DEFAULT_KATO	5

#define NVME_KATO_GRACE		10



#ifdef CONFIG_ARCH_NO_SG_CHAIN

#define  NVME_INLINE_SG_CNT  0