From: Sagi Grimberg <sagi@grimberg.me>
To: Niklas Cassel <Niklas.Cassel@wdc.com>
Cc: "Keith Busch" <kbusch@kernel.org>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"hch@lst.de" <hch@lst.de>,
"linux-block@vger.kernel.org" <linux-block@vger.kernel.org>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"Javier González" <javier.gonz@samsung.com>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
"Johannes Thumshirn" <Johannes.Thumshirn@wdc.com>,
"Matias Bjorling" <Matias.Bjorling@wdc.com>,
"Daniel Wagner" <dwagner@suse.de>
Subject: Re: [PATCHv3 3/5] nvme: implement I/O Command Sets Command Set support
Date: Tue, 23 Jun 2020 16:20:45 -0700 [thread overview]
Message-ID: <9c710c06-5be7-5aff-d919-883e19dfaa44@grimberg.me> (raw)
In-Reply-To: <20200623112551.GB117742@localhost.localdomain>
On 6/23/20 4:25 AM, Niklas Cassel wrote:
> On Tue, Jun 23, 2020 at 01:53:47AM -0700, Sagi Grimberg wrote:
>>
>>
>> On 6/22/20 9:25 AM, Keith Busch wrote:
>>> From: Niklas Cassel <niklas.cassel@wdc.com>
>>>
>>> Implements support for the I/O Command Sets command set. The command set
>>> introduces a method to enumerate multiple command sets per namespace. If
>>> the command set is exposed, this method for enumeration will be used
>>> instead of the traditional method that uses the CC.CSS register command
>>> set register for command set identification.
>>>
>>> For namespaces where the Command Set Identifier is not supported or
>>> recognized, the specific namespace will not be created.
>>>
>>> Reviewed-by: Javier González <javier.gonz@samsung.com>
>>> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
>>> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
>>> Reviewed-by: Matias Bjørling <matias.bjorling@wdc.com>
>>> Reviewed-by: Daniel Wagner <dwagner@suse.de>
>>> Signed-off-by: Niklas Cassel <niklas.cassel@wdc.com>
>>> ---
>>> drivers/nvme/host/core.c | 48 +++++++++++++++++++++++++++++++++-------
>>> drivers/nvme/host/nvme.h | 1 +
>>> include/linux/nvme.h | 19 ++++++++++++++--
>>> 3 files changed, 58 insertions(+), 10 deletions(-)
>>>
>>> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
>>> index 9491dbcfe81a..45a3cb5a35bd 100644
>>> --- a/drivers/nvme/host/core.c
>>> +++ b/drivers/nvme/host/core.c
>>> @@ -1056,8 +1056,13 @@ static int nvme_identify_ctrl(struct nvme_ctrl *dev, struct nvme_id_ctrl **id)
>>> return error;
>>> }
>>> +static bool nvme_multi_css(struct nvme_ctrl *ctrl)
>>> +{
>>> + return (ctrl->ctrl_config & NVME_CC_CSS_MASK) == NVME_CC_CSS_CSI;
>>> +}
>>> +
>>> static int nvme_process_ns_desc(struct nvme_ctrl *ctrl, struct nvme_ns_ids *ids,
>>> - struct nvme_ns_id_desc *cur)
>>> + struct nvme_ns_id_desc *cur, bool *csi_seen)
>>> {
>>> const char *warn_str = "ctrl returned bogus length:";
>>> void *data = cur;
>>> @@ -1087,6 +1092,15 @@ static int nvme_process_ns_desc(struct nvme_ctrl *ctrl, struct nvme_ns_ids *ids,
>>> }
>>> uuid_copy(&ids->uuid, data + sizeof(*cur));
>>> return NVME_NIDT_UUID_LEN;
>>> + case NVME_NIDT_CSI:
>>> + if (cur->nidl != NVME_NIDT_CSI_LEN) {
>>> + dev_warn(ctrl->device, "%s %d for NVME_NIDT_CSI\n",
>>> + warn_str, cur->nidl);
>>> + return -1;
>>> + }
>>> + memcpy(&ids->csi, data + sizeof(*cur), NVME_NIDT_CSI_LEN);
>>> + *csi_seen = true;
>>> + return NVME_NIDT_CSI_LEN;
>>> default:
>>> /* Skip unknown types */
>>> return cur->nidl;
>>> @@ -1097,10 +1111,9 @@ static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
>>> struct nvme_ns_ids *ids)
>>> {
>>> struct nvme_command c = { };
>>> - int status;
>>> + bool csi_seen = false;
>>> + int status, pos, len;
>>> void *data;
>>> - int pos;
>>> - int len;
>>> c.identify.opcode = nvme_admin_identify;
>>> c.identify.nsid = cpu_to_le32(nsid);
>>> @@ -1130,13 +1143,19 @@ static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
>>> if (cur->nidl == 0)
>>> break;
>>> - len = nvme_process_ns_desc(ctrl, ids, cur);
>>> + len = nvme_process_ns_desc(ctrl, ids, cur, &csi_seen);
>>> if (len < 0)
>>> goto free_data;
>>> len += sizeof(*cur);
>>> }
>>> free_data:
>>> + if (!status && nvme_multi_css(ctrl) && !csi_seen) {
>>
>> We will clear the status if we detect a path error, that is to
>> avoid needlessly removing the ns for path failures, so you should
>> check at the goto site.
>
> The problem is that this check has to be done after checking all the ns descs,
> so this check to be done as the final thing, at least after processing all the
> ns descs. No matter if nvme_process_ns_desc() returned an error, or if
> simply NVME_NIDT_CSI wasn't part of the ns desc list, so the loop reached the
> end without error.
>
> Even if the nvme command failed and the status was cleared:
>
> if (status > 0 && !(status & NVME_SC_DNR))
> status = 0;
>
> we still need to return an error, if (nvme_multi_css(ctrl) && !csi_seen).
> (Not reporting a CSI when nvme_multi_css() is enabled, is fatal.)
>
> That is why the code looks like it does.
>
> I guess we could do something like this, which does the same thing,
> but perhaps is a bit clearer:
>
> diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
> index e95f0c498a6b..bef687b9a277 100644
> --- a/drivers/nvme/host/core.c
> +++ b/drivers/nvme/host/core.c
> @@ -1160,8 +1160,10 @@ static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
> * Don't treat an error as fatal, as we potentially already
> * have a NGUID or EUI-64.
> */
> - if (status > 0 && !(status & NVME_SC_DNR))
> + if (status > 0 && !(status & NVME_SC_DNR)) {
> status = 0;
> + goto csi_check;
> + }
I think its the opposite. If we failed with DNR, you should assume
that either the controller wants the host to retry, or its a
path/transport error. So we need to leave this namespace alone and
assume that when the host is connected back to the controller, the
scan_work will revalidate again.
So you should fail the csi_check only if you see a DNR error status.
next prev parent reply other threads:[~2020-06-23 23:20 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-22 16:25 [PATCHv3 0/5] nvme support for zoned namespace command set Keith Busch
2020-06-22 16:25 ` [PATCHv3 1/5] block: add capacity field to zone descriptors Keith Busch
2020-06-23 6:15 ` Hannes Reinecke
2020-06-23 8:44 ` Sagi Grimberg
2020-06-26 12:17 ` Jens Axboe
2020-06-22 16:25 ` [PATCHv3 2/5] null_blk: introduce zone capacity for zoned device Keith Busch
2020-06-23 6:16 ` Hannes Reinecke
2020-06-23 8:45 ` Sagi Grimberg
2020-06-22 16:25 ` [PATCHv3 3/5] nvme: implement I/O Command Sets Command Set support Keith Busch
2020-06-23 6:20 ` Hannes Reinecke
2020-06-23 9:20 ` Niklas Cassel
2020-06-23 14:25 ` Keith Busch
2020-06-23 8:53 ` Sagi Grimberg
2020-06-23 11:25 ` Niklas Cassel
2020-06-23 14:59 ` Keith Busch
2020-06-23 22:10 ` Keith Busch
2020-06-23 23:17 ` Sagi Grimberg
2020-06-24 17:25 ` Keith Busch
2020-06-24 17:46 ` Sagi Grimberg
2020-06-24 18:03 ` Keith Busch
2020-06-24 18:28 ` Sagi Grimberg
2020-06-24 18:33 ` Sagi Grimberg
2020-06-24 18:40 ` Keith Busch
2020-06-24 19:03 ` Sagi Grimberg
2020-06-24 21:49 ` Keith Busch
2020-06-24 22:54 ` Sagi Grimberg
2020-06-24 23:54 ` Keith Busch
2020-06-23 23:20 ` Sagi Grimberg [this message]
2020-06-26 8:54 ` Christoph Hellwig
2020-06-22 16:25 ` [PATCHv3 4/5] nvme: support for multi-command set effects Keith Busch
2020-06-23 6:21 ` Hannes Reinecke
2020-06-23 17:43 ` Sagi Grimberg
2020-06-22 16:25 ` [PATCHv3 5/5] nvme: support for zoned namespaces Keith Busch
2020-06-22 16:48 ` Johannes Thumshirn
2020-06-23 6:23 ` Hannes Reinecke
2020-06-23 17:45 ` Sagi Grimberg
2020-06-24 9:11 ` Javier González
2020-06-29 13:53 ` Johannes Thumshirn
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