[PATCH v5] drivers/net: process the result of hdlc_open() and add call of hdlc_close() in uhdlc_close()

[Alexandra Diupina]

Process the result of hdlc_open() and call uhdlc_close()
in case of an error. It is necessary to pass the error
code up the control flow, similar to a possible
error in request_irq().
Also add a hdlc_close() call to the uhdlc_close()
because the comment to hdlc_close() says it must be called
by the hardware driver when the HDLC device is being closed

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: c19b6d246a35 ("drivers/net: support hdlc function for QE-UCC")
Signed-off-by: Alexandra Diupina <adiup...@astralinux.ru>
---
v5: do some refactoring as Paolo Abeni <pab...@redhat.com> and 
Christophe Leroy <christophe.le...@csgroup.eu> suggested
v4: undo all the things done prior to hdlc_open() as 
Jakub Kicinski <k...@kernel.org> suggested, 
add hdlc_close() call to the uhdlc_close() to match the function comment, 
add uhdlc_close() declaration to the top of the file not to put the 
uhdlc_close() function definition before uhdlc_open()
v3: Fix the commits tree
v2: Remove the 'rc' variable (stores the return value of the 
hdlc_open()) as Christophe Leroy <christophe.le...@csgroup.eu> suggested
 drivers/net/wan/fsl_ucc_hdlc.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wan/fsl_ucc_hdlc.c b/drivers/net/wan/fsl_ucc_hdlc.c
index 47c2ad7a3e42..fd50bb313b92 100644
--- a/drivers/net/wan/fsl_ucc_hdlc.c
+++ b/drivers/net/wan/fsl_ucc_hdlc.c
@@ -34,6 +34,8 @@
 #define TDM_PPPOHT_SLIC_MAXIN
 #define RX_BD_ERRORS (R_CD_S | R_OV_S | R_CR_S | R_AB_S | R_NO_S | R_LG_S)
 
+static int uhdlc_close(struct net_device *dev);
+
 static struct ucc_tdm_info utdm_primary_info = {
        .uf_info = {
                .tsa = 0,
@@ -708,6 +710,7 @@ static int uhdlc_open(struct net_device *dev)
        hdlc_device *hdlc = dev_to_hdlc(dev);
        struct ucc_hdlc_private *priv = hdlc->priv;
        struct ucc_tdm *utdm = priv->utdm;
+       int rc = 0;
 
        if (priv->hdlc_busy != 1) {
                if (request_irq(priv->ut_info->uf_info.irq,
@@ -731,10 +734,13 @@ static int uhdlc_open(struct net_device *dev)
                napi_enable(&priv->napi);
                netdev_reset_queue(dev);
                netif_start_queue(dev);
-               hdlc_open(dev);
+
+               rc = hdlc_open(dev);
+               if (rc)
+                       uhdlc_close(dev);
        }
 
-       return 0;
+       return rc;
 }
 
 static void uhdlc_memclean(struct ucc_hdlc_private *priv)
@@ -824,6 +830,8 @@ static int uhdlc_close(struct net_device *dev)
        netdev_reset_queue(dev);
        priv->hdlc_busy = 0;
 
+       hdlc_close(dev);
+
        return 0;
 }
 
-- 
2.30.2