[PATCH v2 2/2] PCI: switchtec: Return -EFAULT for copy_to_user() errors

Bjorn Helgaas
2022-12-16T16:22:15Z

From: Bjorn Helgaas <bhelgaas@google.com>

switchtec_dev_read() didn't handle copy_to_user() errors correctly: it
assigned "rc = -EFAULT", but actually returned either "size", -ENXIO, or
-EBADMSG instead.

Update the failure cases to unlock mrpc_mutex and return -EFAULT directly.

Fixes: 080b47def5e5 ("MicroSemi Switchtec management interface driver")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/switch/switchtec.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index d7ae84070e29..0ac9d4488210 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -606,16 +606,16 @@ static ssize_t switchtec_dev_read(struct file *filp, char __user *data,
rc = copy_to_user(data, &stuser->return_code,
sizeof(stuser->return_code));
if (rc) {
- rc = -EFAULT;
- goto out;
+ mutex_unlock(&stdev->mrpc_mutex);
+ return -EFAULT;
}

data += sizeof(stuser->return_code);
rc = copy_to_user(data, &stuser->data,
size - sizeof(stuser->return_code));
if (rc) {
- rc = -EFAULT;
- goto out;
+ mutex_unlock(&stdev->mrpc_mutex);
+ return -EFAULT;
}

stuser_set_state(stuser, MRPC_IDLE);
--
2.25.1