[PATCH v2 wireless 2/3] wifi: rt2x00: replace open-coded IE search with cfg80211_find_ie()

[PATCH v2 wireless 2/3] wifi: rt2x00: replace open-coded IE search with cfg80211_find_ie()

[Tristan Madani]

rt2x00lib_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: 1c0bcf89d85cc ("rt2x00: Add autowake support for USB hardware")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
 .../net/wireless/ralink/rt2x00/rt2x00dev.c    | 30 +++++--------------
 1 file changed, 7 insertions(+), 23 deletions(-)

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
index 4d94b7062f440..921383a630bf2 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
@@ -557,26 +557,6 @@ void rt2x00lib_txdone_noinfo(struct queue_entry *entry, u32 status)
 }
 EXPORT_SYMBOL_GPL(rt2x00lib_txdone_noinfo);
 
-static u8 *rt2x00lib_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;
-}
-
 static void rt2x00lib_sleep(struct work_struct *work)
 {
 	struct rt2x00_dev *rt2x00dev =
@@ -642,9 +622,10 @@ static void rt2x00lib_rxdone_check_ps(struct rt2x00_dev *rt2x00dev,
 				      struct sk_buff *skb,
 				      struct rxdone_entry_desc *rxdesc)
 {
-	struct ieee80211_hdr *hdr = (void *) skb->data;
+	struct ieee80211_hdr *hdr = (void *)skb->data;
+	struct ieee80211_mgmt *mgmt = (void *)skb->data;
 	struct ieee80211_tim_ie *tim_ie;
-	u8 *tim;
+	const u8 *tim;
 	u8 tim_len;
 	bool cam;
 
@@ -666,7 +647,10 @@ static void rt2x00lib_rxdone_check_ps(struct rt2x00_dev *rt2x00dev,
 
 	rt2x00dev->last_beacon = jiffies;
 
-	tim = rt2x00lib_find_ie(skb->data, skb->len - FCS_LEN, WLAN_EID_TIM);
+	tim = cfg80211_find_ie(WLAN_EID_TIM, mgmt->u.beacon.variable,
+			       (skb->len - FCS_LEN) -
+			       offsetof(struct ieee80211_mgmt,
+					u.beacon.variable));
 	if (!tim)
 		return;
 
-- 
2.47.3

Re: [PATCH v2 wireless 2/3] wifi: rt2x00: replace open-coded IE search with cfg80211_find_ie()

[Stanislaw Gruszka]

On Mon, Oct 26, 2026 at 10:32:13PM +0000, Tristan Madani wrote:
> rt2x00lib_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: 1c0bcf89d85cc ("rt2x00: Add autowake support for USB hardware")
> Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>

> ---
>  .../net/wireless/ralink/rt2x00/rt2x00dev.c    | 30 +++++--------------
>  1 file changed, 7 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
> index 4d94b7062f440..921383a630bf2 100644
> --- a/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
> +++ b/drivers/net/wireless/ralink/rt2x00/rt2x00dev.c
> @@ -557,26 +557,6 @@ void rt2x00lib_txdone_noinfo(struct queue_entry *entry, u32 status)
>  }
>  EXPORT_SYMBOL_GPL(rt2x00lib_txdone_noinfo);
>  
> -static u8 *rt2x00lib_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;
> -}
> -
>  static void rt2x00lib_sleep(struct work_struct *work)
>  {
>  	struct rt2x00_dev *rt2x00dev =
> @@ -642,9 +622,10 @@ static void rt2x00lib_rxdone_check_ps(struct rt2x00_dev *rt2x00dev,
>  				      struct sk_buff *skb,
>  				      struct rxdone_entry_desc *rxdesc)
>  {
> -	struct ieee80211_hdr *hdr = (void *) skb->data;
> +	struct ieee80211_hdr *hdr = (void *)skb->data;
> +	struct ieee80211_mgmt *mgmt = (void *)skb->data;
>  	struct ieee80211_tim_ie *tim_ie;
> -	u8 *tim;
> +	const u8 *tim;
>  	u8 tim_len;
>  	bool cam;
>  
> @@ -666,7 +647,10 @@ static void rt2x00lib_rxdone_check_ps(struct rt2x00_dev *rt2x00dev,
>  
>  	rt2x00dev->last_beacon = jiffies;
>  
> -	tim = rt2x00lib_find_ie(skb->data, skb->len - FCS_LEN, WLAN_EID_TIM);
> +	tim = cfg80211_find_ie(WLAN_EID_TIM, mgmt->u.beacon.variable,
> +			       (skb->len - FCS_LEN) -
> +			       offsetof(struct ieee80211_mgmt,
> +					u.beacon.variable));
>  	if (!tim)
>  		return;
>  
> -- 
> 2.47.3
>