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Petersen" , John Meneghini , Chris Leech , linux-kernel@vger.kernel.org Subject: Re: [PATCH v1] nvmet: Add traffic based keep alive support to configfs Message-ID: <20260922221201.GE2931-mkhalfella@purestorage.com> References: <20260922202257.1434980-1-jtaubepe@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260922202257.1434980-1-jtaubepe@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260922_151205_841073_9874DD7E X-CRM114-Status: GOOD ( 27.67 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org 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 > --- > 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 >