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powerpc/papr_scm: Reduce error severity if nvdimm stats inaccessible

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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>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210508043642.114076-1-vaibhav@linux.ibm.com
This commit is contained in:
Vaibhav Jain 2021-05-08 10:06:42 +05:30 committed by Michael Ellerman
parent 13c7dad951
commit f3f6d18417
1 changed files with 7 additions and 0 deletions
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7
arch/powerpc/platforms/pseries/papr_scm.c
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@ -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);