[PATCH v2] brcm80211: fmac: Add error handling forbrcmf_usb_dl_writeimage()

[Wentao Liang <vulab@iscas.ac.cn>]

The function brcmf_usb_dl_writeimage() calls the function
brcmf_usb_dl_cmd() but dose not check its return value. The
'state.state' and the 'state.bytes' are uninitialized if the
function brcmf_usb_dl_cmd() fails. It is dangerous to use
uninitialized variables in the conditions.

Add error handling for brcmf_usb_dl_cmd() to jump to error
handling path if the brcmf_usb_dl_cmd() fails and the
'state.state' and the 'state.bytes' are uninitialized.

Improve the error message to report more detailed error
information.

Fixes: 71bb244ba2fd ("brcm80211: fmac: add USB support for bcm43235/6/8 chipsets")
Cc: stable@vger.kernel.org # v3.4+
Signed-off-by: Wentao Liang <vulab@iscas.ac.cn>
---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
index 2821c27f317e..d06c724f63d9 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/usb.c
@@ -896,14 +896,16 @@ brcmf_usb_dl_writeimage(struct brcmf_usbdev_info *devinfo, u8 *fw, int fwlen)
 	}
 
 	/* 1) Prepare USB boot loader for runtime image */
-	brcmf_usb_dl_cmd(devinfo, DL_START, &state, sizeof(state));
+	err = brcmf_usb_dl_cmd(devinfo, DL_START, &state, sizeof(state));
+	if (err)
+		goto fail;
 
 	rdlstate = le32_to_cpu(state.state);
 	rdlbytes = le32_to_cpu(state.bytes);
 
 	/* 2) Check we are in the Waiting state */
 	if (rdlstate != DL_WAITING) {
-		brcmf_err("Failed to DL_START\n");
+		brcmf_err("Invalid DL state: %u\n", rdlstate);
 		err = -EINVAL;
 		goto fail;
 	}
-- 
2.42.0.windows.2