From: Segher Boessenkool <segher@kernel.crashing.org>
To: Vaibhav Jain <vaibhav@linux.ibm.com>
Cc: Ira Weiny <ira.weiny@intel.com>,
Santosh Sivaraj <santosh@fossix.org>,
linux-nvdimm@lists.01.org,
"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
linux-kernel@vger.kernel.org,
Steven Rostedt <rostedt@goodmis.org>,
"Oliver O'Halloran" <oohall@gmail.com>,
Dan Williams <dan.j.williams@intel.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v10 6/6] powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH
Date: Sat, 6 Jun 2020 13:09:10 -0500 [thread overview]
Message-ID: <20200606180910.GW31009@gate.crashing.org> (raw)
In-Reply-To: <87wo4kfk58.fsf@linux.ibm.com>
On Sat, Jun 06, 2020 at 06:04:11PM +0530, Vaibhav Jain wrote:
> >> + /* update health struct with various flags derived from health bitmap */
> >> + health = (struct nd_papr_pdsm_health) {
> >> + .dimm_unarmed = p->health_bitmap & PAPR_PMEM_UNARMED_MASK,
> >> + .dimm_bad_shutdown = p->health_bitmap & PAPR_PMEM_BAD_SHUTDOWN_MASK,
> >> + .dimm_bad_restore = p->health_bitmap & PAPR_PMEM_BAD_RESTORE_MASK,
> >> + .dimm_encrypted = p->health_bitmap & PAPR_PMEM_ENCRYPTED,
> >> + .dimm_locked = p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >> + .dimm_scrubbed = p->health_bitmap & PAPR_PMEM_SCRUBBED_AND_LOCKED,
> >
> > Are you sure these work? These are not assignments to a bool so I don't think
> > gcc will do what you want here.
> Yeah, somehow this slipped by and didnt show up in my tests. I checked
> the assembly dump and seems GCC was silently skipping initializing these
> fields without making any noise.
It's not "skipping" that, it initialises the field to 0, just like your
code said it should :-)
If you think GCC should warn for this, please open a PR? It is *normal*
for bit-fields to be truncated from what is assigned to it, but maybe we
could warn for it in the 1-bit case (we currently don't seem to, even
when the bit-field type is _Bool).
Thanks,
Segher
prev parent reply other threads:[~2020-06-06 18:10 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-04 23:41 [PATCH v10 0/6] powerpc/papr_scm: Add support for reporting nvdimm health Vaibhav Jain
2020-06-04 23:41 ` [PATCH v10 1/6] powerpc: Document details on H_SCM_HEALTH hcall Vaibhav Jain
2020-06-04 23:41 ` [PATCH v10 2/6] seq_buf: Export seq_buf_printf Vaibhav Jain
2020-06-04 23:41 ` [PATCH v10 3/6] powerpc/papr_scm: Fetch nvdimm health information from PHYP Vaibhav Jain
2020-06-04 23:41 ` [PATCH v10 4/6] powerpc/papr_scm: Improve error logging and handling papr_scm_ndctl() Vaibhav Jain
2020-06-05 17:13 ` Ira Weiny
2020-06-05 19:49 ` Dan Williams
2020-06-06 11:21 ` Vaibhav Jain
2020-06-04 23:41 ` [PATCH v10 5/6] ndctl/papr_scm,uapi: Add support for PAPR nvdimm specific methods Vaibhav Jain
2020-06-05 19:49 ` Ira Weiny
2020-06-05 20:58 ` Dan Williams
2020-06-04 23:41 ` [PATCH v10 6/6] powerpc/papr_scm: Implement support for PAPR_PDSM_HEALTH Vaibhav Jain
2020-06-05 18:36 ` Ira Weiny
2020-06-06 12:34 ` Vaibhav Jain
2020-06-06 18:09 ` Segher Boessenkool [this message]
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