From: Vaibhav Jain <vajain21@vajain21.in.ibm.com.in.ibm.com>
To: Dan Williams <dan.j.williams@intel.com>, Jeff Moyer <jmoyer@redhat.com>
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>,
linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
linux-nvdimm <linux-nvdimm@lists.01.org>
Subject: Re: [PATCH] libnvdimm/bus: return the outvar 'cmd_rc' error code in __nd_ioctl()
Date: Mon, 02 Mar 2020 09:51:37 +0530 [thread overview]
Message-ID: <87y2sjtmi6.fsf@vajain21.in.ibm.com> (raw)
In-Reply-To: <CAPcyv4hE_FG0YZXJVA1G=CBq8b9e0K54jxk5Sq5UKU-dnWT2Kg@mail.gmail.com>
Hi Dan,
Apologies for responding late to this. My response below
Dan Williams <dan.j.williams@intel.com> writes:
> On Tue, Feb 18, 2020 at 1:03 PM Dan Williams <dan.j.williams@intel.com> wrote:
>>
>> On Tue, Feb 18, 2020 at 1:00 PM Jeff Moyer <jmoyer@redhat.com> wrote:
>> >
>> > Vaibhav Jain <vaibhav@linux.ibm.com> writes:
>> >
>> > > Presently the error code returned via out variable 'cmd_rc' from the
>> > > nvdimm-bus controller function is ignored when called from
>> > > __nd_ioctl() and never communicated back to user-space code that called
>> > > an ioctl on dimm/bus.
>> > >
>> > > This minor patch updates __nd_ioctl() to propagate the value of out
>> > > variable 'cmd_rc' back to user-space in case it reports an error.
>> > >
>> > > Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
>> > > ---
>> > > drivers/nvdimm/bus.c | 5 +++++
>> > > 1 file changed, 5 insertions(+)
>> > >
>> > > diff --git a/drivers/nvdimm/bus.c b/drivers/nvdimm/bus.c
>> > > index a8b515968569..5b687a27fdf2 100644
>> > > --- a/drivers/nvdimm/bus.c
>> > > +++ b/drivers/nvdimm/bus.c
>> > > @@ -1153,6 +1153,11 @@ static int __nd_ioctl(struct nvdimm_bus *nvdimm_bus, struct nvdimm *nvdimm,
>> > > if (rc < 0)
>> > > goto out_unlock;
>> > >
>> > > + if (cmd_rc < 0) {
>> > > + rc = cmd_rc;
>> > > + goto out_unlock;
>> > > + }
>> > > +
>> > > if (!nvdimm && cmd == ND_CMD_CLEAR_ERROR && cmd_rc >= 0) {
>> > > struct nd_cmd_clear_error *clear_err = buf;
>> >
>> > Looks good to me.
>> >
>> > Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
>>
>> Applied.
>
> Unapplied. This breaks the NVDIMM unit test, and now that I look
> closer you are likely overlooking the fact that cmd_rc is a
> translation of the firmware status, while the ioctl rc is whether the
> command was successfully submitted. If you want the equivalent of
> cmd_rc in userspace you need to translate the firmware status. See
> ndctl_cmd_submit_xlat() in libndctl as an example of how the
> equivalent of cmd_rc is generated from the firmware status.
This seems to be departure from rest of the libndvdimm where a non zero
value of out-var 'cmd_rc' is treated as an error and communicated back to the
caller.
However I agree to the points you made that semantics for __nd_ioctl()
are different hence 'cmd_rc' need not be treated the same way as others.
I think it will be better if these points are documented as
code-comments in this function to make it more clearer as to why
negative value 'cmd_rd' will be ignored and how userspace can get hold
of it if needed.
--
Vaibhav Jain <vaibhav@linux.ibm.com>
Linux Technology Center, IBM India Pvt. Ltd.
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prev parent reply other threads:[~2020-03-02 4:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-22 15:53 [PATCH] libnvdimm/bus: return the outvar 'cmd_rc' error code in __nd_ioctl() Vaibhav Jain
2020-02-18 21:00 ` Jeff Moyer
2020-02-18 21:03 ` Dan Williams
2020-02-29 2:37 ` Dan Williams
2020-03-02 4:21 ` Vaibhav Jain [this message]
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