[PATCH] mac80211: remove fragmentation offload functionality

[PATCH] mac80211: remove fragmentation offload functionality

[Johannes Berg]

There's no driver that actually does fragmentation on the
device, and the callback is buggy (when it returns an error,
mac80211's fragmentation status is changed so reading the
frag threshold from userspace reads the new value despite
the error). Let's just remove it, if we really find some
hardware supporting it we can add it back later.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
---
Unless anybody knows a work-in-progress driver that needs this, in which
case we should fix it? Speak up now if you do.

 include/net/mac80211.h |    5 -----
 net/mac80211/tx.c      |    1 -
 net/mac80211/wext.c    |    8 --------
 3 files changed, 14 deletions(-)

--- everything.orig/include/net/mac80211.h	2008-12-08 21:54:08.000000000 +0100
+++ everything/include/net/mac80211.h	2008-12-08 21:54:21.000000000 +0100
@@ -1253,10 +1253,6 @@ enum ieee80211_ampdu_mlme_action {
  *
  * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
  *
- * @set_frag_threshold: Configuration of fragmentation threshold. Assign this if
- *	the device does fragmentation by itself; if this method is assigned then
- *	the stack will not do fragmentation.
- *
  * @sta_notify: Notifies low level driver about addition or removal of an
  *	associated station, AP, IBSS/WDS/mesh peer etc. Must be atomic.
  *
@@ -1326,7 +1322,6 @@ struct ieee80211_ops {
 	void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
 			     u32 *iv32, u16 *iv16);
 	int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
-	int (*set_frag_threshold)(struct ieee80211_hw *hw, u32 value);
 	void (*sta_notify)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 			enum sta_notify_cmd, struct ieee80211_sta *sta);
 	void (*sta_notify_ps)(struct ieee80211_hw *hw,
--- everything.orig/net/mac80211/tx.c	2008-12-08 21:52:57.000000000 +0100
+++ everything/net/mac80211/tx.c	2008-12-08 21:54:21.000000000 +0100
@@ -1003,7 +1003,6 @@ __ieee80211_tx_prepare(struct ieee80211_
 	if (tx->flags & IEEE80211_TX_FRAGMENTED) {
 		if ((tx->flags & IEEE80211_TX_UNICAST) &&
 		    skb->len + FCS_LEN > local->fragmentation_threshold &&
-		    !local->ops->set_frag_threshold &&
 		    !(info->flags & IEEE80211_TX_CTL_AMPDU))
 			tx->flags |= IEEE80211_TX_FRAGMENTED;
 		else
--- everything.orig/net/mac80211/wext.c	2008-12-08 21:52:57.000000000 +0100
+++ everything/net/mac80211/wext.c	2008-12-08 21:54:21.000000000 +0100
@@ -639,14 +639,6 @@ static int ieee80211_ioctl_siwfrag(struc
 		local->fragmentation_threshold = frag->value & ~0x1;
 	}
 
-	/* If the wlan card performs fragmentation in hardware/firmware,
-	 * configure it here */
-
-	if (local->ops->set_frag_threshold)
-		return local->ops->set_frag_threshold(
-			local_to_hw(local),
-			local->fragmentation_threshold);
-
 	return 0;
 }
 

Re: [PATCH] mac80211: remove fragmentation offload functionality

[Ivo van Doorn]

On Tuesday 09 December 2008, Johannes Berg wrote:
> There's no driver that actually does fragmentation on the
> device, and the callback is buggy (when it returns an error,
> mac80211's fragmentation status is changed so reading the
> frag threshold from userspace reads the new value despite
> the error). Let's just remove it, if we really find some
> hardware supporting it we can add it back later.
> 
> Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> ---
> Unless anybody knows a work-in-progress driver that needs this, in which
> case we should fix it? Speak up now if you do.

For rt2800{pci,usb} the set_frag_threshold is not implemented, so it won't
provide problems with those drivers.

Ivo

>  include/net/mac80211.h |    5 -----
>  net/mac80211/tx.c      |    1 -
>  net/mac80211/wext.c    |    8 --------
>  3 files changed, 14 deletions(-)
> 
> --- everything.orig/include/net/mac80211.h	2008-12-08 21:54:08.000000000 +0100
> +++ everything/include/net/mac80211.h	2008-12-08 21:54:21.000000000 +0100
> @@ -1253,10 +1253,6 @@ enum ieee80211_ampdu_mlme_action {
>   *
>   * @set_rts_threshold: Configuration of RTS threshold (if device needs it)
>   *
> - * @set_frag_threshold: Configuration of fragmentation threshold. Assign this if
> - *	the device does fragmentation by itself; if this method is assigned then
> - *	the stack will not do fragmentation.
> - *
>   * @sta_notify: Notifies low level driver about addition or removal of an
>   *	associated station, AP, IBSS/WDS/mesh peer etc. Must be atomic.
>   *
> @@ -1326,7 +1322,6 @@ struct ieee80211_ops {
>  	void (*get_tkip_seq)(struct ieee80211_hw *hw, u8 hw_key_idx,
>  			     u32 *iv32, u16 *iv16);
>  	int (*set_rts_threshold)(struct ieee80211_hw *hw, u32 value);
> -	int (*set_frag_threshold)(struct ieee80211_hw *hw, u32 value);
>  	void (*sta_notify)(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  			enum sta_notify_cmd, struct ieee80211_sta *sta);
>  	void (*sta_notify_ps)(struct ieee80211_hw *hw,
> --- everything.orig/net/mac80211/tx.c	2008-12-08 21:52:57.000000000 +0100
> +++ everything/net/mac80211/tx.c	2008-12-08 21:54:21.000000000 +0100
> @@ -1003,7 +1003,6 @@ __ieee80211_tx_prepare(struct ieee80211_
>  	if (tx->flags & IEEE80211_TX_FRAGMENTED) {
>  		if ((tx->flags & IEEE80211_TX_UNICAST) &&
>  		    skb->len + FCS_LEN > local->fragmentation_threshold &&
> -		    !local->ops->set_frag_threshold &&
>  		    !(info->flags & IEEE80211_TX_CTL_AMPDU))
>  			tx->flags |= IEEE80211_TX_FRAGMENTED;
>  		else
> --- everything.orig/net/mac80211/wext.c	2008-12-08 21:52:57.000000000 +0100
> +++ everything/net/mac80211/wext.c	2008-12-08 21:54:21.000000000 +0100
> @@ -639,14 +639,6 @@ static int ieee80211_ioctl_siwfrag(struc
>  		local->fragmentation_threshold = frag->value & ~0x1;
>  	}
>  
> -	/* If the wlan card performs fragmentation in hardware/firmware,
> -	 * configure it here */
> -
> -	if (local->ops->set_frag_threshold)
> -		return local->ops->set_frag_threshold(
> -			local_to_hw(local),
> -			local->fragmentation_threshold);
> -
>  	return 0;
>  }
>  
> 
> 
> 

Re: [PATCH] mac80211: remove fragmentation offload functionality

[Johannes Berg]

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On Tue, 2008-12-09 at 21:36 +0100, Ivo van Doorn wrote:
> On Tuesday 09 December 2008, Johannes Berg wrote:
> > There's no driver that actually does fragmentation on the
> > device, and the callback is buggy (when it returns an error,
> > mac80211's fragmentation status is changed so reading the
> > frag threshold from userspace reads the new value despite
> > the error). Let's just remove it, if we really find some
> > hardware supporting it we can add it back later.
> > 
> > Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
> > ---
> > Unless anybody knows a work-in-progress driver that needs this, in which
> > case we should fix it? Speak up now if you do.
> 
> For rt2800{pci,usb} the set_frag_threshold is not implemented, so it won't
> provide problems with those drivers.

That's why I asked, thanks :)

johannes

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