Subject: [PATCH 11/11] PCI: shpchp: Use sysfs_emit() and sysfs_emit_at() in "show" functions

From: Krzysztof Wilczyński <[email-masked]>
Date: Mon, 10 May 2021 04:14:24 +0000

The sysfs_emit() and sysfs_emit_at() functions were introduced to make
it less ambiguous which function is preferred when writing to the output
buffer in a device attribute's "show" callback [1].

Convert the PCI sysfs object "show" functions from sprintf(), snprintf()
and scnprintf() to sysfs_emit() and sysfs_emit_at() accordingly, as the
latter is aware of the PAGE_SIZE buffer and correctly returns the number
of bytes written into the buffer.

No functional change intended.

[1] Documentation/filesystems/sysfs.rst

Related to:
  commit ad025f8e46f3 ("PCI/sysfs: Use sysfs_emit() and sysfs_emit_at() in "show" functions")

Signed-off-by: Krzysztof Wilczyński <[email-masked]>
---
 drivers/pci/hotplug/shpchp_sysfs.c | 38 +++++++++++++++++-------------
 1 file changed, 21 insertions(+), 17 deletions(-)

diff --git a/drivers/pci/hotplug/shpchp_sysfs.c b/drivers/pci/hotplug/shpchp_sysfs.c
index 45658bb5c554..64beed7a26be 100644
--- a/drivers/pci/hotplug/shpchp_sysfs.c
+++ b/drivers/pci/hotplug/shpchp_sysfs.c
@@ -24,50 +24,54 @@
 static ssize_t show_ctrl(struct device *dev, struct device_attribute *attr, char *buf)
 {
 	struct pci_dev *pdev;
-	char *out = buf;
 	int index, busnr;
 	struct resource *res;
 	struct pci_bus *bus;
+	size_t len = 0;
 
 	pdev = to_pci_dev(dev);
 	bus = pdev->subordinate;
 
-	out += sprintf(buf, "Free resources: memory\n");
+	len += sysfs_emit_at(buf, len, "Free resources: memory\n");
 	pci_bus_for_each_resource(bus, res, index) {
 		if (res && (res->flags & IORESOURCE_MEM) &&
 				!(res->flags & IORESOURCE_PREFETCH)) {
-			out += sprintf(out, "start = %8.8llx, length = %8.8llx\n",
-				       (unsigned long long)res->start,
-				       (unsigned long long)resource_size(res));
+			len += sysfs_emit_at(buf, len,
+					     "start = %8.8llx, length = %8.8llx\n",
+					     (unsigned long long)res->start,
+					     (unsigned long long)resource_size(res));
 		}
 	}
-	out += sprintf(out, "Free resources: prefetchable memory\n");
+	len += sysfs_emit_at(buf, len, "Free resources: prefetchable memory\n");
 	pci_bus_for_each_resource(bus, res, index) {
 		if (res && (res->flags & IORESOURCE_MEM) &&
 			       (res->flags & IORESOURCE_PREFETCH)) {
-			out += sprintf(out, "start = %8.8llx, length = %8.8llx\n",
-				       (unsigned long long)res->start,
-				       (unsigned long long)resource_size(res));
+			len += sysfs_emit_at(buf, len,
+					     "start = %8.8llx, length = %8.8llx\n",
+					     (unsigned long long)res->start,
+					     (unsigned long long)resource_size(res));
 		}
 	}
-	out += sprintf(out, "Free resources: IO\n");
+	len += sysfs_emit_at(buf, len, "Free resources: IO\n");
 	pci_bus_for_each_resource(bus, res, index) {
 		if (res && (res->flags & IORESOURCE_IO)) {
-			out += sprintf(out, "start = %8.8llx, length = %8.8llx\n",
-				       (unsigned long long)res->start,
-				       (unsigned long long)resource_size(res));
+			len += sysfs_emit_at(buf, len,
+					     "start = %8.8llx, length = %8.8llx\n",
+					     (unsigned long long)res->start,
+					     (unsigned long long)resource_size(res));
 		}
 	}
-	out += sprintf(out, "Free resources: bus numbers\n");
+	len += sysfs_emit_at(buf, len, "Free resources: bus numbers\n");
 	for (busnr = bus->busn_res.start; busnr <= bus->busn_res.end; busnr++) {
 		if (!pci_find_bus(pci_domain_nr(bus), busnr))
 			break;
 	}
 	if (busnr < bus->busn_res.end)
-		out += sprintf(out, "start = %8.8x, length = %8.8x\n",
-				busnr, (int)(bus->busn_res.end - busnr));
+		len += sysfs_emit_at(buf, len,
+				     "start = %8.8x, length = %8.8x\n",
+				     busnr, (int)(bus->busn_res.end - busnr));
 
-	return out - buf;
+	return len;
 }
 static DEVICE_ATTR(ctrl, S_IRUGO, show_ctrl, NULL);
 
-- 
2.31.1