PCI/sysfs: Return -EINVAL consistently from "store" functions

Most of the "store" functions that handle userspace input via sysfs return
-EINVAL should the value fail validation and/or type conversion.  This
error code is a clear message to userspace that the value is not a valid
input.

However, some of the "show" functions return input parsing error codes
as-is, which may be either -EINVAL or -ERANGE.  The former would often be
from kstrtobool(), and the latter typically from other kstr*() functions
such as kstrtou8(), kstrtou32(), kstrtoint(), etc.

-EINVAL is commonly returned as the error code to indicate that the value
provided is invalid, but -ERANGE is not very useful in userspace.

Therefore, normalize the return error code to be -EINVAL for when the
validation and/or type conversion fails.

Link: https://lore.kernel.org/r/20210915230127.2495723-2-kw@linux.com
Signed-off-by: Krzysztof Wilczyński <kw@linux.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 9 insertions, 11 deletions

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 6832e161be1c..a092fc0c665d 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -273,15 +273,14 @@ static ssize_t enable_store(struct device *dev, struct device_attribute *attr,
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	unsigned long val;
-	ssize_t result;
+	ssize_t result = 0;
 
 	/* this can crash the machine when done on the "wrong" device */
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	result = kstrtoul(buf, 0, &val);
-	if (result < 0)
-		return result;
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
 
 	device_lock(dev);
 	if (dev->driver)
@@ -313,14 +312,13 @@ static ssize_t numa_node_store(struct device *dev,
 			       size_t count)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	int node, ret;
+	int node;
 
 	if (!capable(CAP_SYS_ADMIN))
 		return -EPERM;
 
-	ret = kstrtoint(buf, 0, &node);
-	if (ret)
-		return ret;
+	if (kstrtoint(buf, 0, &node) < 0)
+		return -EINVAL;
 
 	if ((node < 0 && node != NUMA_NO_NODE) || node >= MAX_NUMNODES)
 		return -EINVAL;
@@ -1340,10 +1338,10 @@ static ssize_t reset_store(struct device *dev, struct device_attribute *attr,
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
 	unsigned long val;
-	ssize_t result = kstrtoul(buf, 0, &val);
+	ssize_t result;
 
-	if (result < 0)
-		return result;
+	if (kstrtoul(buf, 0, &val) < 0)
+		return -EINVAL;
 
 	if (val != 1)
 		return -EINVAL;