[PATCH] mwifiex: remove function pointer check

[tr...@redhat.com]

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

clang static analyzer reports this problem

init.c:739:8: warning: Called function pointer
is null (null dereference)
ret = adapter->if_ops.check_fw_status( ...
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In mwifiex_dnld_fw, there is an earlier check for check_fw_status(),
The check was introduced for usb support at the same time this
check in _mwifiex_fw_dpc() was made

if (adapter->if_ops.dnld_fw) {
ret = adapter->if_ops.dnld_fw(adapter, &fw);
} else {
ret = mwifiex_dnld_fw(adapter, &fw);
}

And a dnld_fw function initialized as part the usb's
mwifiex_if_ops.

The other instances of mwifiex_if_ops for pci and sdio
both set check_fw_status.

So the first check is not needed and can be removed.

Fixes: 4daffe354366 ("mwifiex: add support for Marvell USB8797 chipset")
Signed-off-by: Tom Rix <tr...@redhat.com>
---
drivers/net/wireless/marvell/mwifiex/init.c | 14 ++++++--------
1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/init.c b/drivers/net/wireless/marvell/mwifiex/init.c
index 82d69bc3aaaf..f006a3d72b40 100644
--- a/drivers/net/wireless/marvell/mwifiex/init.c
+++ b/drivers/net/wireless/marvell/mwifiex/init.c
@@ -695,14 +695,12 @@ int mwifiex_dnld_fw(struct mwifiex_adapter *adapter,
int ret;
u32 poll_num = 1;

- if (adapter->if_ops.check_fw_status) {
- /* check if firmware is already running */
- ret = adapter->if_ops.check_fw_status(adapter, poll_num);
- if (!ret) {
- mwifiex_dbg(adapter, MSG,
- "WLAN FW already running! Skip FW dnld\n");
- return 0;
- }
+ /* check if firmware is already running */
+ ret = adapter->if_ops.check_fw_status(adapter, poll_num);
+ if (!ret) {
+ mwifiex_dbg(adapter, MSG,
+ "WLAN FW already running! Skip FW dnld\n");
+ return 0;
}

/* check if we are the winner for downloading FW */
--
2.18.1

[Nathan Chancellor]

On Sun, Sep 06, 2020 at 01:05:48PM -0700, tr...@redhat.com wrote:
> From: Tom Rix <tr...@redhat.com>
>
> clang static analyzer reports this problem
>
> init.c:739:8: warning: Called function pointer
> is null (null dereference)
> ret = adapter->if_ops.check_fw_status( ...
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> In mwifiex_dnld_fw, there is an earlier check for check_fw_status(),
> The check was introduced for usb support at the same time this
> check in _mwifiex_fw_dpc() was made
>
> if (adapter->if_ops.dnld_fw) {
> ret = adapter->if_ops.dnld_fw(adapter, &fw);
> } else {
> ret = mwifiex_dnld_fw(adapter, &fw);
> }
>
> And a dnld_fw function initialized as part the usb's
> mwifiex_if_ops.
>
> The other instances of mwifiex_if_ops for pci and sdio
> both set check_fw_status.
>
> So the first check is not needed and can be removed.
>
> Fixes: 4daffe354366 ("mwifiex: add support for Marvell USB8797 chipset")
> Signed-off-by: Tom Rix <tr...@redhat.com>

Indeed, on the surface, mwifiex_dnld_fw assumes that check_fw_status()
cannot be NULL because it will always be called at the end of the
function even if the first check is skipped.

Reviewed-by: Nathan Chancellor <natecha...@gmail.com>

> --
> You received this message because you are subscribed to the Google Groups "Clang Built Linux" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to clang-built-li...@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/clang-built-linux/20200906200548.18053-1-trix%40redhat.com.

[Kalle Valo]

tr...@redhat.com wrote:

> From: Tom Rix <tr...@redhat.com>
>
> clang static analyzer reports this problem
>
> init.c:739:8: warning: Called function pointer
> is null (null dereference)
> ret = adapter->if_ops.check_fw_status( ...
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> In mwifiex_dnld_fw, there is an earlier check for check_fw_status(),
> The check was introduced for usb support at the same time this
> check in _mwifiex_fw_dpc() was made
>
> if (adapter->if_ops.dnld_fw) {
> ret = adapter->if_ops.dnld_fw(adapter, &fw);
> } else {
> ret = mwifiex_dnld_fw(adapter, &fw);
> }
>
> And a dnld_fw function initialized as part the usb's
> mwifiex_if_ops.
>
> The other instances of mwifiex_if_ops for pci and sdio
> both set check_fw_status.
>
> So the first check is not needed and can be removed.
>
> Fixes: 4daffe354366 ("mwifiex: add support for Marvell USB8797 chipset")
> Signed-off-by: Tom Rix <tr...@redhat.com>

> Reviewed-by: Nathan Chancellor <natecha...@gmail.com>

Patch applied to wireless-drivers-next.git, thanks.

eb2c6ca2db8c mwifiex: remove function pointer check

--
https://patchwork.kernel.org/patch/11759719/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches