* [PATCH v1] nvmet: Add traffic based keep alive support to configfs
@ 2026-09-22 20:22 Jesse Taube
2026-09-22 22:12 ` Mohamed Khalfella
0 siblings, 1 reply; 2+ messages in thread
From: Jesse Taube @ 2026-09-22 20:22 UTC (permalink / raw)
To: linux-nvme
Cc: Christoph Hellwig, Sagi Grimberg, Chaitanya Kulkarni,
Martin K. Petersen, John Meneghini, Chris Leech, linux-kernel,
Mohamed Khalfella, Jesse Taube
Add the ability to turn on and off tbkas (traffic based keep alive
support) via configfs. This is useful for testing and debugging.
Signed-off-by: Jesse Taube <jtaubepe@redhat.com>
---
drivers/nvme/target/admin-cmd.c | 4 +++-
drivers/nvme/target/configfs.c | 27 +++++++++++++++++++++++++++
drivers/nvme/target/core.c | 3 ++-
drivers/nvme/target/nvmet.h | 1 +
4 files changed, 33 insertions(+), 2 deletions(-)
diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
index 7764a3c0195c..e734e4b68784 100644
--- a/drivers/nvme/target/admin-cmd.c
+++ b/drivers/nvme/target/admin-cmd.c
@@ -696,7 +696,9 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
/* XXX: figure out what to do about RTD3R/RTD3 */
id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
- ctratt = NVME_CTRL_ATTR_HID_128_BIT | NVME_CTRL_ATTR_TBKAS;
+ ctratt = NVME_CTRL_ATTR_HID_128_BIT;
+ if (subsys->tbkas)
+ ctratt |= NVME_CTRL_ATTR_TBKAS;
if (nvmet_is_pci_ctrl(ctrl))
ctratt |= NVME_CTRL_ATTR_RHII;
id->ctratt = cpu_to_le32(ctratt);
diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
index 6286e38436dd..5766e594e724 100644
--- a/drivers/nvme/target/configfs.c
+++ b/drivers/nvme/target/configfs.c
@@ -1369,6 +1369,32 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
}
CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
+static ssize_t nvmet_subsys_attr_tbkas_show(struct config_item *item,
+ char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%d\n", to_subsys(item)->tbkas);
+}
+
+static ssize_t nvmet_subsys_attr_tbkas_store(struct config_item *item,
+ const char *page, size_t count)
+{
+ struct nvmet_subsys *subsys = to_subsys(item);
+ bool tbkas;
+
+ if (subsys->subsys_discovered) {
+ pr_err("Can't set traffic based keep alive support. %d is already assigned\n",
+ subsys->tbkas);
+ return -EINVAL;
+ }
+
+ if (kstrtobool(page, &tbkas))
+ return -EINVAL;
+
+ subsys->tbkas = tbkas;
+ return count;
+}
+CONFIGFS_ATTR(nvmet_subsys_, attr_tbkas);
+
static ssize_t nvmet_subsys_attr_cntlid_min_show(struct config_item *item,
char *page)
{
@@ -1706,6 +1732,7 @@ static struct configfs_attribute *nvmet_subsys_attrs[] = {
&nvmet_subsys_attr_attr_qid_max,
&nvmet_subsys_attr_attr_ieee_oui,
&nvmet_subsys_attr_attr_firmware,
+ &nvmet_subsys_attr_attr_tbkas,
#ifdef CONFIG_BLK_DEV_INTEGRITY
&nvmet_subsys_attr_attr_pi_enable,
#endif
diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
index 43871a8f56ca..20aeb9624be0 100644
--- a/drivers/nvme/target/core.c
+++ b/drivers/nvme/target/core.c
@@ -1227,7 +1227,7 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_sq *sq,
goto fail;
}
- if (sq->ctrl)
+ if (sq->ctrl && sq->ctrl->subsys->tbkas)
sq->ctrl->reset_tbkas = true;
return true;
@@ -1865,6 +1865,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
}
subsys->ieee_oui = 0;
+ subsys->tbkas = true;
subsys->firmware_rev = kstrndup(UTS_RELEASE, NVMET_FR_MAX_SIZE, GFP_KERNEL);
if (!subsys->firmware_rev) {
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index dbda55895f4f..241eac4fa969 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -343,6 +343,7 @@ struct nvmet_subsys {
bool subsys_discovered;
char *subsysnqn;
bool pi_support;
+ bool tbkas;
struct config_group group;
--
2.55.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH v1] nvmet: Add traffic based keep alive support to configfs
2026-09-22 20:22 [PATCH v1] nvmet: Add traffic based keep alive support to configfs Jesse Taube
@ 2026-09-22 22:12 ` Mohamed Khalfella
0 siblings, 0 replies; 2+ messages in thread
From: Mohamed Khalfella @ 2026-09-22 22:12 UTC (permalink / raw)
To: Jesse Taube
Cc: linux-nvme, Christoph Hellwig, Sagi Grimberg, Chaitanya Kulkarni,
Martin K. Petersen, John Meneghini, Chris Leech, linux-kernel
On Tue 2026-09-22 16:22:56 -0400, Jesse Taube wrote:
> Add the ability to turn on and off tbkas (traffic based keep alive
> support) via configfs. This is useful for testing and debugging.
Yep, this is indeed useful.
>
> Signed-off-by: Jesse Taube <jtaubepe@redhat.com>
> ---
> drivers/nvme/target/admin-cmd.c | 4 +++-
> drivers/nvme/target/configfs.c | 27 +++++++++++++++++++++++++++
> drivers/nvme/target/core.c | 3 ++-
> drivers/nvme/target/nvmet.h | 1 +
> 4 files changed, 33 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
> index 7764a3c0195c..e734e4b68784 100644
> --- a/drivers/nvme/target/admin-cmd.c
> +++ b/drivers/nvme/target/admin-cmd.c
> @@ -696,7 +696,9 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
>
> /* XXX: figure out what to do about RTD3R/RTD3 */
> id->oaes = cpu_to_le32(NVMET_AEN_CFG_OPTIONAL);
> - ctratt = NVME_CTRL_ATTR_HID_128_BIT | NVME_CTRL_ATTR_TBKAS;
> + ctratt = NVME_CTRL_ATTR_HID_128_BIT;
> + if (subsys->tbkas)
> + ctratt |= NVME_CTRL_ATTR_TBKAS;
> if (nvmet_is_pci_ctrl(ctrl))
> ctratt |= NVME_CTRL_ATTR_RHII;
> id->ctratt = cpu_to_le32(ctratt);
> diff --git a/drivers/nvme/target/configfs.c b/drivers/nvme/target/configfs.c
> index 6286e38436dd..5766e594e724 100644
> --- a/drivers/nvme/target/configfs.c
> +++ b/drivers/nvme/target/configfs.c
> @@ -1369,6 +1369,32 @@ static ssize_t nvmet_subsys_attr_serial_store(struct config_item *item,
> }
> CONFIGFS_ATTR(nvmet_subsys_, attr_serial);
>
> +static ssize_t nvmet_subsys_attr_tbkas_show(struct config_item *item,
> + char *page)
> +{
> + return snprintf(page, PAGE_SIZE, "%d\n", to_subsys(item)->tbkas);
> +}
> +
> +static ssize_t nvmet_subsys_attr_tbkas_store(struct config_item *item,
> + const char *page, size_t count)
> +{
> + struct nvmet_subsys *subsys = to_subsys(item);
> + bool tbkas;
> +
> + if (subsys->subsys_discovered) {
> + pr_err("Can't set traffic based keep alive support. %d is already assigned\n",
> + subsys->tbkas);
> + return -EINVAL;
> + }
Would it be okay to fore reconnecting existing controllers when
subsys->tbkas changes? Similar to what attr_qid_max does?
I think this will make testing more flexible by avoiding need to
recreate the subsystem in order to test tkbas on/off. Also, you may
consider adding ctrl->tkbas, again just like qid_max. It will be copied
from subsys in nvmet_alloc_ctrl() under subsys->lock.
> +
> + if (kstrtobool(page, &tbkas))
> + return -EINVAL;
> +
> + subsys->tbkas = tbkas;
> + return count;
> +}
> +CONFIGFS_ATTR(nvmet_subsys_, attr_tbkas);
> +
> static ssize_t nvmet_subsys_attr_cntlid_min_show(struct config_item *item,
> char *page)
> {
> @@ -1706,6 +1732,7 @@ static struct configfs_attribute *nvmet_subsys_attrs[] = {
> &nvmet_subsys_attr_attr_qid_max,
> &nvmet_subsys_attr_attr_ieee_oui,
> &nvmet_subsys_attr_attr_firmware,
> + &nvmet_subsys_attr_attr_tbkas,
> #ifdef CONFIG_BLK_DEV_INTEGRITY
> &nvmet_subsys_attr_attr_pi_enable,
> #endif
> diff --git a/drivers/nvme/target/core.c b/drivers/nvme/target/core.c
> index 43871a8f56ca..20aeb9624be0 100644
> --- a/drivers/nvme/target/core.c
> +++ b/drivers/nvme/target/core.c
> @@ -1227,7 +1227,7 @@ bool nvmet_req_init(struct nvmet_req *req, struct nvmet_sq *sq,
> goto fail;
> }
>
> - if (sq->ctrl)
> + if (sq->ctrl && sq->ctrl->subsys->tbkas)
> sq->ctrl->reset_tbkas = true;
If you add ctrl->tkbas, then this will be sq->ctrl->tkbas. It is
guaranteed not to change during the lifetime of the controller.
>
> return true;
> @@ -1865,6 +1865,7 @@ struct nvmet_subsys *nvmet_subsys_alloc(const char *subsysnqn,
> }
>
> subsys->ieee_oui = 0;
> + subsys->tbkas = true;
>
> subsys->firmware_rev = kstrndup(UTS_RELEASE, NVMET_FR_MAX_SIZE, GFP_KERNEL);
> if (!subsys->firmware_rev) {
> diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
> index dbda55895f4f..241eac4fa969 100644
> --- a/drivers/nvme/target/nvmet.h
> +++ b/drivers/nvme/target/nvmet.h
> @@ -343,6 +343,7 @@ struct nvmet_subsys {
> bool subsys_discovered;
> char *subsysnqn;
> bool pi_support;
> + bool tbkas;
>
> struct config_group group;
>
> --
> 2.55.0
>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2026-09-22 22:12 UTC | newest]
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