Re: [PATCH v2 7/7] nvme: fcloop: Add set_marginal_rport to sysfs

[Hannes Reinecke <hare@suse.de>]

On 9/23/26 4:56 PM, Jesse Taube wrote:
> On Mon, Sep 21, 2026 at 10:03 AM Hannes Reinecke <hare@suse.de> wrote:
>>
>> On 9/2/26 10:05 PM, Jesse Taube wrote:
>>> To allow testing of multipath failover, add a sysfs attribute to set a
>>> remote port as marginal. This will allow the fcloop LLDD to set the
>>> marginal flag on a remote port, simulating a marginal link.
>>>
>>> Example:
>>> Turn on marginal for a remote port matching wwnn and wwpn:
>>> `echo 'wwnn=0x200000109b5f2956,wwpn=0x100000109b5f2956,marginal=1' >
>>> /sys/class/fcloop/ctl/set_marginal_rport`
>>>
>>> Turn off marginal for a remote port matching wwnn and wwpn:
>>> `echo 'wwnn=0x200000109b5f2956,wwpn=0x100000109b5f2956,marginal=0' >
>>> /sys/class/fcloop/ctl/set_marginal_rport`
>>>
>>> Suggested-by: John Meneghini <jmeneghi@redhat.com>
>>> Signed-off-by: Jesse Taube <jtaubepe@redhat.com>
>>> V10 -> V1:
>>>    - New patch
>>> V1 -> V2:
>>>    - Fix reference count leak in error path
>>> ---
>>>    drivers/nvme/target/fcloop.c | 50 ++++++++++++++++++++++++++++++++++++
>>>    1 file changed, 50 insertions(+)
>>>
>>> diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
>>> index b63af3b643a6..9977c2a71bd5 100644
>>> --- a/drivers/nvme/target/fcloop.c
>>> +++ b/drivers/nvme/target/fcloop.c
>>> @@ -6,6 +6,7 @@
>>>    #include <linux/module.h>
>>>    #include <linux/parser.h>
>>>    #include <uapi/scsi/fc/fc_fs.h>
>>> +#include <uapi/scsi/fc/fc_els.h>
>>>
>>>    #include "../host/nvme.h"
>>>    #include "../target/nvmet.h"
>>> @@ -21,6 +22,7 @@ enum {
>>>        NVMF_OPT_FCADDR         = 1 << 3,
>>>        NVMF_OPT_LPWWNN         = 1 << 4,
>>>        NVMF_OPT_LPWWPN         = 1 << 5,
>>> +     NVMF_OPT_MARGINAL       = 1 << 6,
>>>    };
>>>
>>>    struct fcloop_ctrl_options {
>>> @@ -31,6 +33,7 @@ struct fcloop_ctrl_options {
>>>        u32                     fcaddr;
>>>        u64                     lpwwnn;
>>>        u64                     lpwwpn;
>>> +     u32                     marginal;
>>>    };
>>>
>>>    static const match_table_t opt_tokens = {
>>> @@ -40,6 +43,7 @@ static const match_table_t opt_tokens = {
>>>        { NVMF_OPT_FCADDR,      "fcaddr=%x"     },
>>>        { NVMF_OPT_LPWWNN,      "lpwwnn=%s"     },
>>>        { NVMF_OPT_LPWWPN,      "lpwwpn=%s"     },
>>> +     { NVMF_OPT_MARGINAL,    "marginal=%d"   },
>>>        { NVMF_OPT_ERR,         NULL            }
>>>    };
>>>
>>> @@ -120,6 +124,13 @@ fcloop_parse_options(struct fcloop_ctrl_options *opts,
>>>                        }
>>>                        opts->lpwwpn = token64;
>>>                        break;
>>> +             case NVMF_OPT_MARGINAL:
>>> +                     if (match_int(args, &token)) {
>>> +                             ret = -EINVAL;
>>> +                             goto out_free_options;
>>> +                     }
>>> +                     opts->marginal = token;
>>> +                     break;
>>>                default:
>>>                        pr_warn("unknown parameter or missing value '%s'\n", p);
>>>                        ret = -EINVAL;
>>> @@ -199,6 +210,9 @@ fcloop_parse_nm_options(struct device *dev, u64 *nname, u64 *pname,
>>>
>>>    #define TGTPORT_OPTS        (NVMF_OPT_WWNN | NVMF_OPT_WWPN)
>>>
>>> +#define MARGINAL_OPTS        (NVMF_OPT_WWNN | NVMF_OPT_WWPN | \
>>> +                      NVMF_OPT_MARGINAL)
>>> +
>>>
>>>    static DEFINE_SPINLOCK(fcloop_lock);
>>>    static LIST_HEAD(fcloop_lports);
>>> @@ -1663,6 +1677,40 @@ fcloop_set_cmd_drop(struct device *dev, struct device_attribute *attr,
>>>        return count;
>>>    }
>>>
>>> +static ssize_t
>>> +fcloop_set_marginal_rport(struct device *dev, struct device_attribute *attr,
>>> +             const char *buf, size_t count)
>>> +{
>>> +     struct fcloop_nport *nport;
>>> +     struct fcloop_ctrl_options opts = {};
>>> +     unsigned long flags;
>>> +     int ret;
>>> +
>>> +     ret = fcloop_parse_options(&opts, buf);
>>> +     if (ret)
>>> +             return ret;
>>> +
>>> +     /* everything there ? */
>>> +     if ((opts.mask & MARGINAL_OPTS) != MARGINAL_OPTS)
>>> +             return -EINVAL;
>>> +
>>> +     nport = fcloop_nport_lookup(opts.wwnn, opts.wwpn);
>>> +     if (!nport)
>>> +             return -ENOENT;
>>> +
>>> +     spin_lock_irqsave(&fcloop_lock, flags);
>>> +     if (!nport->rport || !nport->rport->remoteport) {
>>> +             spin_unlock_irqrestore(&fcloop_lock, flags);
>>> +             fcloop_nport_put(nport);
>>> +             return -ENOENT;
>>> +     }
>>> +
>>> +     nvme_fc_set_remoteport_fpin(nport->rport->remoteport, opts.marginal);
>>> +     spin_unlock_irqrestore(&fcloop_lock, flags);
>>> +     fcloop_nport_put(nport);
>>> +
>>> +     return count;
>>> +}
>>>
>>>    static DEVICE_ATTR(add_local_port, 0200, NULL, fcloop_create_local_port);
>>>    static DEVICE_ATTR(del_local_port, 0200, NULL, fcloop_delete_local_port);
>>> @@ -1671,6 +1719,7 @@ static DEVICE_ATTR(del_remote_port, 0200, NULL, fcloop_delete_remote_port);
>>>    static DEVICE_ATTR(add_target_port, 0200, NULL, fcloop_create_target_port);
>>>    static DEVICE_ATTR(del_target_port, 0200, NULL, fcloop_delete_target_port);
>>>    static DEVICE_ATTR(set_cmd_drop, 0200, NULL, fcloop_set_cmd_drop);
>>> +static DEVICE_ATTR(set_marginal_rport, 0200, NULL, fcloop_set_marginal_rport);
>>>
>>>    static struct attribute *fcloop_dev_attrs[] = {
>>>        &dev_attr_add_local_port.attr,
>>> @@ -1680,6 +1729,7 @@ static struct attribute *fcloop_dev_attrs[] = {
>>>        &dev_attr_add_target_port.attr,
>>>        &dev_attr_del_target_port.attr,
>>>        &dev_attr_set_cmd_drop.attr,
>>> +     &dev_attr_set_marginal_rport.attr,
>>>        NULL
>>>    };
>>>
>> Please don't make it a fabrics option.
> 
> What do you mean by fabrics option? How should I fix this?
> 
Your patch does two things; one is to modify the parser in 
fcloop_parse_options, and the other is to implement a new
sysfs rport attribute 'set_marginal_rport()'.
My suggestion is to drop the first part; we really should not start off 
with a marginal port, rather only set ports to marginal during runtime.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich