[PATCH v2] staging: r8188eu: handle rtw_init_netdev_name() failure appropriately

[PATCH v2] staging: r8188eu: handle rtw_init_netdev_name() failure appropriately

[Vihas Mak]

rtw_init_netdev_name() calls dev_alloc_name() which allocates the name
for the device as per the given name format.
The name format is specified by the module parameter "ifname".
It returns a negative err code if the format is invalid. Handle this
error appropriately.
Cancel the timers ininitliazed by rtw_init_drv_sw() before calling
rtw_free_drv_sw() and then proceed to free the adapter.

Also, if register_netdev() fails then goto free_drv_sw instead of
goto handle_dualmac.

Signed-off-by: Vihas Mak <makvihas@gmail.com>
---
v1->v2:
    free the adapter and netdev instead of warning the user about 
    allocation failure.

 drivers/staging/r8188eu/os_dep/usb_intf.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/r8188eu/os_dep/usb_intf.c b/drivers/staging/r8188eu/os_dep/usb_intf.c
index 91792dfd3..85b5d0bd7 100644
--- a/drivers/staging/r8188eu/os_dep/usb_intf.c
+++ b/drivers/staging/r8188eu/os_dep/usb_intf.c
@@ -399,7 +399,11 @@ static struct adapter *rtw_usb_if1_init(struct dvobj_priv *dvobj,
 			DBG_88E("can't get autopm:\n");
 
 	/*  alloc dev name after read efuse. */
-	rtw_init_netdev_name(pnetdev, padapter->registrypriv.ifname);
+	if (rtw_init_netdev_name(pnetdev, padapter->registrypriv.ifname) < 0) {
+		DBG_88E("rtw_init_netdev_name failed, ifname:%s\n",
+			padapter->registrypriv.ifname);
+		goto free_drv_sw;
+	}
 	rtw_macaddr_cfg(padapter->eeprompriv.mac_addr);
 	rtw_init_wifidirect_addrs(padapter, padapter->eeprompriv.mac_addr,
 				  padapter->eeprompriv.mac_addr);
@@ -409,7 +413,7 @@ static struct adapter *rtw_usb_if1_init(struct dvobj_priv *dvobj,
 
 	/* step 6. Tell the network stack we exist */
 	if (register_netdev(pnetdev) != 0)
-		goto handle_dualmac;
+		goto free_drv_sw;
 
 	DBG_88E("bDriverStopped:%d, bSurpriseRemoved:%d, bup:%d, hw_init_completed:%d\n"
 		, padapter->bDriverStopped
@@ -420,6 +424,11 @@ static struct adapter *rtw_usb_if1_init(struct dvobj_priv *dvobj,
 
 	status = _SUCCESS;
 
+free_drv_sw:
+	if (status != _SUCCESS) {
+		rtw_cancel_all_timer(padapter);
+		rtw_free_drv_sw(padapter);
+	}
 handle_dualmac:
 	if (status != _SUCCESS)
 		rtw_handle_dualmac(padapter, 0);
-- 
2.30.2

Re: [PATCH v2] staging: r8188eu: handle rtw_init_netdev_name() failure appropriately

[Dan Carpenter]

On Sun, Jan 23, 2022 at 11:47:35PM +0530, Vihas Mak wrote:
> rtw_init_netdev_name() calls dev_alloc_name() which allocates the name
> for the device as per the given name format.
> The name format is specified by the module parameter "ifname".
> It returns a negative err code if the format is invalid. Handle this
> error appropriately.
> Cancel the timers ininitliazed by rtw_init_drv_sw() before calling
> rtw_free_drv_sw() and then proceed to free the adapter.
> 
> Also, if register_netdev() fails then goto free_drv_sw instead of
> goto handle_dualmac.
> 
> Signed-off-by: Vihas Mak <makvihas@gmail.com>
> ---
> v1->v2:
>     free the adapter and netdev instead of warning the user about 
>     allocation failure.

Thanks!

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>

Of course, all this code is staging code and terrible.  This function
is needlessly difficult to read/review.

TODO: re-write probe error handling

Step 1: Keep the success path and error path separate.

-	status = _SUCCESS;
+	return padapter;

Step 2: Eliminate do-nothing-gotos.  s/goto exit/return NULL/

Step 3: Delete the vfree(pnpi->priv); from rtw_free_netdev() and call
        vfree(pnpi->priv); from probe and rtw_usb_if1_deinit() instead.
        Avoid a layering violation.

Step 4: Every allocation function needs a matching free function.  Move
        the rtw_cancel_all_timer() into the rtw_free_drv_sw() function.
        Open coding it is a layering violation.

Step 5: Get rid of the rtw_handle_dualmac() function.  It has a bad
        name and a global variable.  What is the point of this function?

But that stuff is for later patches.

regards,
dan carpenter

Re: [PATCH v2] staging: r8188eu: handle rtw_init_netdev_name() failure appropriately

[Vihas Mak]

Thanks for reviewing the patch Dan.

>> TODO: re-write probe error handling

Will submit a series of patches in upcoming days, based on the steps
you provided.

On Mon, Jan 24, 2022 at 12:19 PM Dan Carpenter <dan.carpenter@oracle.com> wrote:
>
> On Sun, Jan 23, 2022 at 11:47:35PM +0530, Vihas Mak wrote:
> > rtw_init_netdev_name() calls dev_alloc_name() which allocates the name
> > for the device as per the given name format.
> > The name format is specified by the module parameter "ifname".
> > It returns a negative err code if the format is invalid. Handle this
> > error appropriately.
> > Cancel the timers ininitliazed by rtw_init_drv_sw() before calling
> > rtw_free_drv_sw() and then proceed to free the adapter.
> >
> > Also, if register_netdev() fails then goto free_drv_sw instead of
> > goto handle_dualmac.
> >
> > Signed-off-by: Vihas Mak <makvihas@gmail.com>
> > ---
> > v1->v2:
> >     free the adapter and netdev instead of warning the user about
> >     allocation failure.
>
> Thanks!
>
> Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
>
> Of course, all this code is staging code and terrible.  This function
> is needlessly difficult to read/review.
>
> TODO: re-write probe error handling
>
> Step 1: Keep the success path and error path separate.
>
> -       status = _SUCCESS;
> +       return padapter;
>
> Step 2: Eliminate do-nothing-gotos.  s/goto exit/return NULL/
>
> Step 3: Delete the vfree(pnpi->priv); from rtw_free_netdev() and call
>         vfree(pnpi->priv); from probe and rtw_usb_if1_deinit() instead.
>         Avoid a layering violation.
>
> Step 4: Every allocation function needs a matching free function.  Move
>         the rtw_cancel_all_timer() into the rtw_free_drv_sw() function.
>         Open coding it is a layering violation.
>
> Step 5: Get rid of the rtw_handle_dualmac() function.  It has a bad
>         name and a global variable.  What is the point of this function?
>
> But that stuff is for later patches.
>
> regards,
> dan carpenter
>


-- 
Thanks,
Vihas