[PATCH] USB: serial: mos7720: improve handling of a kmalloc failure in read_mos_reg()

[trix]

From: Tom Rix <t...@redhat.com>

clang static analysis reports this problem

mos7720.c:352:2: warning: Undefined or garbage value returned to caller
        return d;
        ^~~~~~~~

In the parport_mos7715_read_data()'s call to read_mos_reg(), 'd' is
only set after the alloc block.

        buf = kmalloc(1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

Although the problem is reported in parport_most7715_read_data(),
none of the callee's of read_mos_reg() check the return status.

So move the clearing of data to before the malloc.

Fixes: 0d130367abf5 ("USB: serial: mos7720: fix control-message error handling")
Signed-off-by: Tom Rix <t...@redhat.com>
---
 drivers/usb/serial/mos7720.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 41ee2984a0df..23e8162c768b 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -214,6 +214,7 @@ static int read_mos_reg(struct usb_serial *serial, unsigned 
int serial_portnum,
        u8 *buf;
        int status;
 
+       *data = 0;
        buf = kmalloc(1, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;
@@ -227,7 +228,6 @@ static int read_mos_reg(struct usb_serial *serial, unsigned 
int serial_portnum,
                        "mos7720: usb_control_msg() failed: %d\n", status);
                if (status >= 0)
                        status = -EIO;
-               *data = 0;
        }
 
        kfree(buf);
-- 
2.27.0