[PATCH v2 wireless 1/3] wifi: carl9170: replace open-coded IE search with cfg80211_find_ie()

[PATCH v2 wireless 1/3] wifi: carl9170: replace open-coded IE search with cfg80211_find_ie()

[Tristan Madani]

carl9170_find_ie() open-codes the IE search that cfg80211_find_ie()
already provides.  Replace the hand-rolled function with
cfg80211_find_ie() at the single call site.

Fixes: a84fab3cbfdc4 ("carl9170: 802.11 rx/tx processing and usb backend")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
 drivers/net/wireless/ath/carl9170/rx.c | 27 ++++++--------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/drivers/net/wireless/ath/carl9170/rx.c b/drivers/net/wireless/ath/carl9170/rx.c
index fbe46a5e4e415..9db6ac9d6d3c0 100644
--- a/drivers/net/wireless/ath/carl9170/rx.c
+++ b/drivers/net/wireless/ath/carl9170/rx.c
@@ -490,25 +490,6 @@ static struct sk_buff *carl9170_rx_copy_data(u8 *buf, int len)
 	return skb;
 }
 
-static u8 *carl9170_find_ie(u8 *data, unsigned int len, u8 ie)
-{
-	struct ieee80211_mgmt *mgmt = (void *)data;
-	u8 *pos, *end;
-
-	pos = (u8 *)mgmt->u.beacon.variable;
-	end = data + len;
-	while (pos < end) {
-		if (pos + 2 + pos[1] > end)
-			return NULL;
-
-		if (pos[0] == ie)
-			return pos;
-
-		pos += 2 + pos[1];
-	}
-	return NULL;
-}
-
 /*
  * NOTE:
  *
@@ -521,9 +502,10 @@ static u8 *carl9170_find_ie(u8 *data, unsigned int len, u8 ie)
 static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
 {
 	struct ieee80211_hdr *hdr = data;
+	struct ieee80211_mgmt *mgmt = data;
 	struct ieee80211_tim_ie *tim_ie;
 	struct ath_common *common = &ar->common;
-	u8 *tim;
+	const u8 *tim;
 	u8 tim_len;
 	bool cam;
 
@@ -541,7 +523,10 @@ static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
 
 	ar->ps.last_beacon = jiffies;
 
-	tim = carl9170_find_ie(data, len - FCS_LEN, WLAN_EID_TIM);
+	tim = cfg80211_find_ie(WLAN_EID_TIM, mgmt->u.beacon.variable,
+			       (len - FCS_LEN) -
+			       offsetof(struct ieee80211_mgmt,
+					u.beacon.variable));
 	if (!tim)
 		return;
 
-- 
2.47.3

Re: [PATCH v2 wireless 1/3] wifi: carl9170: replace open-coded IE search with cfg80211_find_ie()

[Christian Lamparter]

On 10/26/26 11:32 PM, Tristan Madani wrote:
> carl9170_find_ie() open-codes the IE search that cfg80211_find_ie()
> already provides.  Replace the hand-rolled function with
> cfg80211_find_ie() at the single call site.
> 
> Fixes: a84fab3cbfdc4 ("carl9170: 802.11 rx/tx processing and usb backend")
> Signed-off-by: Tristan Madani <tristan@talencesecurity.com>

Sure!

Acked-by: Christian Lamparter <chunkeey@gmail.com>

> ---
>   drivers/net/wireless/ath/carl9170/rx.c | 27 ++++++--------------------
>   1 file changed, 6 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/carl9170/rx.c b/drivers/net/wireless/ath/carl9170/rx.c
> index fbe46a5e4e415..9db6ac9d6d3c0 100644
> --- a/drivers/net/wireless/ath/carl9170/rx.c
> +++ b/drivers/net/wireless/ath/carl9170/rx.c
 > [...]> @@ -541,7 +523,10 @@ static void carl9170_ps_beacon(struct ar9170 *ar, void *data, unsigned int len)
>   
>   	ar->ps.last_beacon = jiffies;
>   
> -	tim = carl9170_find_ie(data, len - FCS_LEN, WLAN_EID_TIM);
> +	tim = cfg80211_find_ie(WLAN_EID_TIM, mgmt->u.beacon.variable,
> +			       (len - FCS_LEN) -
> +			       offsetof(struct ieee80211_mgmt,
> +					u.beacon.variable));

nit:
If there ever will be a v3. You could consider that the 80 characters per line
is not a strict rule.

This is straight out of "Documentation/process/maintainer-tip.rst:
"The 80 character rule is not a strict rule, so please use common sense when
breaking lines. Especially format strings should never be broken up."

my 2¢:
	tim = cfg80211_find_ie(WLAN_EID_TIM, mgmt->u.beacon.variable,
			       len - FCS_LEN - offsetof(struct ieee80211_mgmt, u.beacon.variable));

Cheers,
Christian