diff mbox series

[v3,25/27] powerpc/powernv/pmem: Expose the serial number in sysfs

Message ID 20200221032720.33893-26-alastair@au1.ibm.com (mailing list archive)
State New, archived
Headers show
Series Add support for OpenCAPI Persistent Memory devices | expand

Commit Message

Alastair D'Silva Feb. 21, 2020, 3:27 a.m. UTC 
From: Alastair D'Silva <alastair@d-silva.org>

This information will be used by ndctl in userspace to help users identify
the device.

Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
---
 arch/powerpc/platforms/powernv/pmem/Makefile  |  2 +-
 arch/powerpc/platforms/powernv/pmem/ocxl.c    |  5 +++
 .../platforms/powernv/pmem/ocxl_internal.h    |  6 +++
 .../platforms/powernv/pmem/ocxl_sysfs.c       | 37 +++++++++++++++++++
 4 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c

Comments

Andrew Donnellan Feb. 28, 2020, 6:25 a.m. UTC | #1 
On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> +int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
> +{
> +	int i, rc;
> +
> +	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
> +		rc = device_create_file(&ocxlpmem->dev, &attrs[i]);
> +		if (rc) {
> +			for (; --i >= 0;)
> +				device_remove_file(&ocxlpmem->dev, &attrs[i]);

I'd rather avoid weird for loop constructs if possible.

Is it actually dangerous to call device_remove_file() on an attr that 
hasn't been added? If not then I'd rather define an err: label and loop 
over the whole array there.
Greg KH Feb. 28, 2020, 7:15 a.m. UTC | #2 
On Fri, Feb 28, 2020 at 05:25:31PM +1100, Andrew Donnellan wrote:
> On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> > +int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
> > +{
> > +	int i, rc;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
> > +		rc = device_create_file(&ocxlpmem->dev, &attrs[i]);
> > +		if (rc) {
> > +			for (; --i >= 0;)
> > +				device_remove_file(&ocxlpmem->dev, &attrs[i]);
> 
> I'd rather avoid weird for loop constructs if possible.
> 
> Is it actually dangerous to call device_remove_file() on an attr that hasn't
> been added? If not then I'd rather define an err: label and loop over the
> whole array there.

None of this should be used at all, just use attribute groups properly
and the driver core will handle this all for you.

device_create/remove_file should never be called by anyone anymore if at all
possible.

thanks,

greg k-h
Alastair D'Silva March 1, 2020, 11:42 p.m. UTC | #3 
On Fri, 2020-02-28 at 08:15 +0100, Greg Kroah-Hartman wrote:
> On Fri, Feb 28, 2020 at 05:25:31PM +1100, Andrew Donnellan wrote:
> > On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> > > +int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
> > > +{
> > > +	int i, rc;
> > > +
> > > +	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
> > > +		rc = device_create_file(&ocxlpmem->dev, &attrs[i]);
> > > +		if (rc) {
> > > +			for (; --i >= 0;)
> > > +				device_remove_file(&ocxlpmem->dev,
> > > &attrs[i]);
> > 
> > I'd rather avoid weird for loop constructs if possible.
> > 
> > Is it actually dangerous to call device_remove_file() on an attr
> > that hasn't
> > been added? If not then I'd rather define an err: label and loop
> > over the
> > whole array there.
> 
> None of this should be used at all, just use attribute groups
> properly
> and the driver core will handle this all for you.
> 
> device_create/remove_file should never be called by anyone anymore if
> at all
> possible.
> 
> thanks,
> 
> greg k-h


Thanks, I'll rework it to use the .groups member of struct pci_driver.
Alastair D'Silva March 2, 2020, 5:38 a.m. UTC | #4 
On Mon, 2020-03-02 at 10:42 +1100, Alastair D'Silva wrote:
> On Fri, 2020-02-28 at 08:15 +0100, Greg Kroah-Hartman wrote:
> > On Fri, Feb 28, 2020 at 05:25:31PM +1100, Andrew Donnellan wrote:
> > > On 21/2/20 2:27 pm, Alastair D'Silva wrote:
> > > > +int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
> > > > +{
> > > > +	int i, rc;
> > > > +
> > > > +	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
> > > > +		rc = device_create_file(&ocxlpmem->dev,
> > > > &attrs[i]);
> > > > +		if (rc) {
> > > > +			for (; --i >= 0;)
> > > > +				device_remove_file(&ocxlpmem-
> > > > >dev,
> > > > &attrs[i]);
> > > 
> > > I'd rather avoid weird for loop constructs if possible.
> > > 
> > > Is it actually dangerous to call device_remove_file() on an attr
> > > that hasn't
> > > been added? If not then I'd rather define an err: label and loop
> > > over the
> > > whole array there.
> > 
> > None of this should be used at all, just use attribute groups
> > properly
> > and the driver core will handle this all for you.
> > 
> > device_create/remove_file should never be called by anyone anymore
> > if
> > at all
> > possible.
> > 
> > thanks,
> > 
> > greg k-h
> 
> Thanks, I'll rework it to use the .groups member of struct
> pci_driver.
> 

I ended up making these available as DIMM attributes instead.
diff mbox series

Patch

diff --git a/arch/powerpc/platforms/powernv/pmem/Makefile b/arch/powerpc/platforms/powernv/pmem/Makefile
index 4ceda25907d4..d02870806f30 100644
--- a/arch/powerpc/platforms/powernv/pmem/Makefile
+++ b/arch/powerpc/platforms/powernv/pmem/Makefile
@@ -4,4 +4,4 @@  ccflags-$(CONFIG_PPC_WERROR)	+= -Werror
 
 obj-$(CONFIG_OCXL_PMEM) += ocxlpmem.o
 
-ocxlpmem-y := ocxl.o ocxl_internal.o
+ocxlpmem-y := ocxl.o ocxl_internal.o ocxl_sysfs.o
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl.c b/arch/powerpc/platforms/powernv/pmem/ocxl.c
index 5cd1b6d78dd6..ec73713d05ad 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl.c
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl.c
@@ -1878,6 +1878,11 @@  static int probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 		goto err;
 	}
 
+	if (ocxlpmem_sysfs_add(ocxlpmem)) {
+		dev_err(&pdev->dev, "Could not create sysfs entries\n");
+		goto err;
+	}
+
 	elapsed = 0;
 	timeout = ocxlpmem->readiness_timeout + ocxlpmem->memory_available_timeout;
 	while (!is_usable(ocxlpmem, false)) {
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
index 0eb7a35d24ae..12304ceace61 100644
--- a/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_internal.h
@@ -246,3 +246,9 @@  int ns_response_handled(const struct ocxlpmem *ocxlpmem);
  */
 void warn_status(const struct ocxlpmem *ocxlpmem, const char *message,
 		 u8 status);
+
+/**
+ * ocxlpmem_sysfs_add() - Create sysfs entries for an OpenCAPI persistent memory device
+ * @ocxlpmem: the device metadata
+ */
+int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem);
diff --git a/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c b/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c
new file mode 100644
index 000000000000..7829e4bc887d
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/pmem/ocxl_sysfs.c
@@ -0,0 +1,37 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2018 IBM Corp.
+
+#include <linux/sysfs.h>
+#include <linux/capability.h>
+#include <linux/limits.h>
+#include <linux/firmware.h>
+#include "ocxl_internal.h"
+
+static ssize_t serial_show(struct device *device, struct device_attribute *attr,
+			   char *buf)
+{
+	struct ocxlpmem *ocxlpmem = container_of(device, struct ocxlpmem, dev);
+	const struct ocxl_fn_config *fn_config = ocxl_function_config(ocxlpmem->ocxl_fn);
+
+	return scnprintf(buf, PAGE_SIZE, "%llu\n", fn_config->serial);
+}
+
+static struct device_attribute attrs[] = {
+	__ATTR_RO(serial),
+};
+
+int ocxlpmem_sysfs_add(struct ocxlpmem *ocxlpmem)
+{
+	int i, rc;
+
+	for (i = 0; i < ARRAY_SIZE(attrs); i++) {
+		rc = device_create_file(&ocxlpmem->dev, &attrs[i]);
+		if (rc) {
+			for (; --i >= 0;)
+				device_remove_file(&ocxlpmem->dev, &attrs[i]);
+
+			return rc;
+		}
+	}
+	return 0;
+}