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 v2] powerpc/papr_scm: Make 'perf_stats' invisible if perf-stats unavailable
Date: Fri,  7 May 2021 17:09:48 +0530	[thread overview]
Message-ID: <20210507113948.38950-1-vaibhav@linux.ibm.com> (raw)

In case performance stats for an nvdimm are not available, reading the
'perf_stats' sysfs file returns an -ENOENT error. A better approach is
to make the 'perf_stats' file entirely invisible to indicate that
performance stats for an nvdimm are unavailable.

So this patch updates 'papr_nd_attribute_group' to add a 'is_visible'
callback implemented as newly introduced 'papr_nd_attribute_visible()'
that returns an appropriate mode in case performance stats aren't
supported in a given nvdimm.

Also the initialization of 'papr_scm_priv.stat_buffer_len' is moved
from papr_scm_nvdimm_init() to papr_scm_probe() so that it value is
available when 'papr_nd_attribute_visible()' is called during nvdimm
initialization.

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

v2:
* Removed a redundant dev_info() from pap_scm_nvdimm_init() [ Aneesh ]
* Marked papr_nd_attribute_visible() as static which also fixed the
  build warning reported by kernel build robot
---
 arch/powerpc/platforms/pseries/papr_scm.c | 35 ++++++++++++++++-------
 1 file changed, 24 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/papr_scm.c b/arch/powerpc/platforms/pseries/papr_scm.c
index e2b69cc3beaf..11e7b90a3360 100644
--- a/arch/powerpc/platforms/pseries/papr_scm.c
+++ b/arch/powerpc/platforms/pseries/papr_scm.c
@@ -907,6 +907,20 @@ static ssize_t flags_show(struct device *dev,
 }
 DEVICE_ATTR_RO(flags);
 
+static umode_t papr_nd_attribute_visible(struct kobject *kobj,
+					 struct attribute *attr, int n)
+{
+	struct device *dev = container_of(kobj, typeof(*dev), kobj);
+	struct nvdimm *nvdimm = to_nvdimm(dev);
+	struct papr_scm_priv *p = nvdimm_provider_data(nvdimm);
+
+	/* For if perf-stats not available remove perf_stats sysfs */
+	if (attr == &dev_attr_perf_stats.attr && p->stat_buffer_len == 0)
+		return 0;
+
+	return attr->mode;
+}
+
 /* papr_scm specific dimm attributes */
 static struct attribute *papr_nd_attributes[] = {
 	&dev_attr_flags.attr,
@@ -916,6 +930,7 @@ static struct attribute *papr_nd_attributes[] = {
 
 static struct attribute_group papr_nd_attribute_group = {
 	.name = "papr",
+	.is_visible = papr_nd_attribute_visible,
 	.attrs = papr_nd_attributes,
 };
 
@@ -931,7 +946,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	struct nd_region_desc ndr_desc;
 	unsigned long dimm_flags;
 	int target_nid, online_nid;
-	ssize_t stat_size;
 
 	p->bus_desc.ndctl = papr_scm_ndctl;
 	p->bus_desc.module = THIS_MODULE;
@@ -1016,16 +1030,6 @@ static int papr_scm_nvdimm_init(struct papr_scm_priv *p)
 	list_add_tail(&p->region_list, &papr_nd_regions);
 	mutex_unlock(&papr_ndr_lock);
 
-	/* Try retriving the stat buffer and see if its supported */
-	stat_size = drc_pmem_query_stats(p, NULL, 0);
-	if (stat_size > 0) {
-		p->stat_buffer_len = stat_size;
-		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
-			p->stat_buffer_len);
-	} else {
-		dev_info(&p->pdev->dev, "Dimm performance stats unavailable\n");
-	}
-
 	return 0;
 
 err:	nvdimm_bus_unregister(p->bus);
@@ -1102,6 +1106,7 @@ static int papr_scm_probe(struct platform_device *pdev)
 	u64 blocks, block_size;
 	struct papr_scm_priv *p;
 	const char *uuid_str;
+	ssize_t stat_size;
 	u64 uuid[2];
 	int rc;
 
@@ -1179,6 +1184,14 @@ static int papr_scm_probe(struct platform_device *pdev)
 	p->res.name  = pdev->name;
 	p->res.flags = IORESOURCE_MEM;
 
+	/* Try retriving the stat buffer and see if its supported */
+	stat_size = drc_pmem_query_stats(p, NULL, 0);
+	if (stat_size > 0) {
+		p->stat_buffer_len = stat_size;
+		dev_dbg(&p->pdev->dev, "Max perf-stat size %lu-bytes\n",
+			p->stat_buffer_len);
+	}
+
 	rc = papr_scm_nvdimm_init(p);
 	if (rc)
 		goto err2;
-- 
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:[~2021-05-07 11:40 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-07 11:39 Vaibhav Jain [this message]
2021-05-12 19:48 ` Dan Williams
2021-05-13  9:26   ` Vaibhav Jain

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=20210507113948.38950-1-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 v2] powerpc/papr_scm: Make '\''perf_stats'\'' invisible if perf-stats unavailable' \
    /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).