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, 6 insertions, 8 deletions

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index dafdc652fcd0..0267977c9f17 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -183,11 +183,10 @@ static ssize_t sriov_vf_msix_count_store(struct device *dev,
 {
 	struct pci_dev *vf_dev = to_pci_dev(dev);
 	struct pci_dev *pdev = pci_physfn(vf_dev);
-	int val, ret;
+	int val, ret = 0;
 
-	ret = kstrtoint(buf, 0, &val);
-	if (ret)
-		return ret;
+	if (kstrtoint(buf, 0, &val) < 0)
+		return -EINVAL;
 
 	if (val < 0)
 		return -EINVAL;
@@ -376,12 +375,11 @@ static ssize_t sriov_numvfs_store(struct device *dev,
 				  const char *buf, size_t count)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
-	int ret;
+	int ret = 0;
 	u16 num_vfs;
 
-	ret = kstrtou16(buf, 0, &num_vfs);
-	if (ret < 0)
-		return ret;
+	if (kstrtou16(buf, 0, &num_vfs) < 0)
+		return -EINVAL;
 
 	if (num_vfs > pci_sriov_get_totalvfs(pdev))
 		return -ERANGE;