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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: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
This commit is contained in:
Hannes Reinecke 2021-04-16 13:46:20 +02:00 committed by Christoph Hellwig
parent 8f864c595b
commit a70b81bd4d
3 changed files with 15 additions and 7 deletions
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17
drivers/nvme/host/core.c
View File

@ -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)

4
drivers/nvme/host/fabrics.c
View File

@ -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;

1
drivers/nvme/host/nvme.h
View File

@ -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