linux-nvdimm.lists.01.org archive mirror
 help / color / mirror / Atom feed
From: Vaibhav Jain <vaibhav@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org, linux-nvdimm@lists.01.org
Cc: Vaibhav Jain <vaibhav@linux.ibm.com>,
	"Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>
Subject: [PATCH v3] powerpc/papr_scm: Reduce error severity if nvdimm stats inaccessible
Date: Sat,  8 May 2021 10:06:42 +0530	[thread overview]
Message-ID: <20210508043642.114076-1-vaibhav@linux.ibm.com> (raw)

Currently drc_pmem_qeury_stats() generates a dev_err in case
"Enable Performance Information Collection" feature is disabled from
HMC or performance stats are not available for an nvdimm. The error is
of the form below:

papr_scm ibm,persistent-memory:ibm,pmemory@44104001: Failed to query
	 performance stats, Err:-10

This error message confuses users as it implies a possible problem
with the nvdimm even though its due to a disabled/unavailable
feature. We fix this by explicitly handling the H_AUTHORITY and
H_UNSUPPORTED errors from the H_SCM_PERFORMANCE_STATS hcall.

In case of H_AUTHORITY error an info message is logged instead of an
error, saying that "Permission denied while accessing performance
stats" and an EPERM error is returned back.

In case of H_UNSUPPORTED error we return a EOPNOTSUPP error back from
drc_pmem_query_stats() indicating that performance stats-query
operation is not supported on this nvdimm.

Fixes: 2d02bf835e57('powerpc/papr_scm: Fetch nvdimm performance stats from PHYP')
Signed-off-by: Vaibhav Jain <vaibhav@linux.ibm.com>
---
Changelog

v3:
* Return EOPNOTSUPP error in case of H_UNSUPPORTED [ Ira ]
* Return EPERM in case of H_AUTHORITY [ Ira ]
* Updated patch description

v2:
* Updated the message logged in case of H_AUTHORITY error [ Ira ]
* Switched from dev_warn to dev_info in case of H_AUTHORITY error.
* Instead of -EPERM return -EACCESS for H_AUTHORITY error.
* Added explicit handling of H_UNSUPPORTED error.
---
 arch/powerpc/platforms/pseries/papr_scm.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index ef26fe40efb0..e2b69cc3beaf 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -310,6 +310,13 @@ static ssize_t drc_pmem_query_stats(struct papr_scm_priv *p,
 		dev_err(&p->pdev->dev,
 			"Unknown performance stats, Err:0x%016lX\n", ret[0]);
 		return -ENOENT;
+	} else if (rc == H_AUTHORITY) {
+		dev_info(&p->pdev->dev,
+			 "Permission denied while accessing performance stats");
+		return -EPERM;
+	} else if (rc == H_UNSUPPORTED) {
+		dev_dbg(&p->pdev->dev, "Performance stats unsupported\n");
+		return -EOPNOTSUPP;
 	} else if (rc != H_SUCCESS) {
 		dev_err(&p->pdev->dev,
 			"Failed to query performance stats, Err:%lld\n", rc);
-- 
2.31.1
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

             reply	other threads:[~2021-05-08  4:37 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-08  4:36 Vaibhav Jain [this message]
2021-05-08 15:11 ` Ira Weiny
2021-05-19  7:06 ` kajoljain

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20210508043642.114076-1-vaibhav@linux.ibm.com \
    --to=vaibhav@linux.ibm.com \
    --cc=aneesh.kumar@linux.ibm.com \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linuxppc-dev@lists.ozlabs.org \
    --cc=mpe@ellerman.id.au \
    --subject='Re: [PATCH v3] powerpc/papr_scm: Reduce error severity if nvdimm stats inaccessible' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).