mac80211: support hardware TX fragmentation offload

The lower driver is notified when the fragmentation threshold changes
and upon a reconfig of the interface.

If the driver supports hardware TX fragmentation, don't fragment
packets in the stack.

Signed-off-by: Arik Nemtsov <arik@wizery.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 54 insertions, 2 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 18bd0e550600..3df12f7d0cfe 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1299,6 +1299,13 @@ static int ieee80211_set_wiphy_params(struct wiphy *wiphy, u32 changed)
         struct ieee80211_local *local = wiphy_priv(wiphy);
         int err;
 
+        if (changed & WIPHY_PARAM_FRAG_THRESHOLD) {
+                err = drv_set_frag_threshold(local, wiphy->frag_threshold);
+
+                if (err)
+                        return err;
+        }
+
         if (changed & WIPHY_PARAM_COVERAGE_CLASS) {
                 err = drv_set_coverage_class(local, wiphy->coverage_class);
 
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 16983825f8e8..79019f94f621 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -233,6 +233,20 @@ static inline void drv_get_tkip_seq(struct ieee80211_local *local,
         trace_drv_get_tkip_seq(local, hw_key_idx, iv32, iv16);
 }
 
+static inline int drv_set_frag_threshold(struct ieee80211_local *local,
+                                        u32 value)
+{
+        int ret = 0;
+
+        might_sleep();
+
+        trace_drv_set_frag_threshold(local, value);
+        if (local->ops->set_frag_threshold)
+                ret = local->ops->set_frag_threshold(&local->hw, value);
+        trace_drv_return_int(local, ret);
+        return ret;
+}
+
 static inline int drv_set_rts_threshold(struct ieee80211_local *local,
                                         u32 value)
 {
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 6831fb1641c8..431d65500d6a 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -531,6 +531,27 @@ TRACE_EVENT(drv_get_tkip_seq,
         )
 );
 
+TRACE_EVENT(drv_set_frag_threshold,
+        TP_PROTO(struct ieee80211_local *local, u32 value),
+
+        TP_ARGS(local, value),
+
+        TP_STRUCT__entry(
+                LOCAL_ENTRY
+                __field(u32, value)
+        ),
+
+        TP_fast_assign(
+                LOCAL_ASSIGN;
+                __entry->value = value;
+        ),
+
+        TP_printk(
+                LOCAL_PR_FMT " value:%d",
+                LOCAL_PR_ARG, __entry->value
+        )
+);
+
 TRACE_EVENT(drv_set_rts_threshold,
         TP_PROTO(struct ieee80211_local *local, u32 value),
 
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 96c594309506..b392876af7d8 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1033,6 +1033,7 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
         struct ieee80211_radiotap_header *rthdr =
                 (struct ieee80211_radiotap_header *) skb->data;
         struct ieee80211_supported_band *sband;
+        bool hw_frag;
         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
         int ret = ieee80211_radiotap_iterator_init(&iterator, rthdr, skb->len,
                                                    NULL);
@@ -1042,6 +1043,9 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
         info->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
         tx->flags &= ~IEEE80211_TX_FRAGMENTED;
 
+        /* packet is fragmented in HW if we have a non-NULL driver callback */
+        hw_frag = (tx->local->ops->set_frag_threshold != NULL);
+
         /*
          * for every radiotap entry that is present
          * (ieee80211_radiotap_iterator_next returns -ENOENT when no more
@@ -1078,7 +1082,8 @@ static bool __ieee80211_parse_tx_radiotap(struct ieee80211_tx_data *tx,
                         }
                         if (*iterator.this_arg & IEEE80211_RADIOTAP_F_WEP)
                                 info->flags &= ~IEEE80211_TX_INTFL_DONT_ENCRYPT;
-                        if (*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG)
+                        if ((*iterator.this_arg & IEEE80211_RADIOTAP_F_FRAG) &&
+                                                                !hw_frag)
                                 tx->flags |= IEEE80211_TX_FRAGMENTED;
                         break;
 
@@ -1181,8 +1186,10 @@ ieee80211_tx_prepare(struct ieee80211_sub_if_data *sdata,
         /*
          * Set this flag (used below to indicate "automatic fragmentation"),
          * it will be cleared/left by radiotap as desired.
+         * Only valid when fragmentation is done by the stack.
          */
-        tx->flags |= IEEE80211_TX_FRAGMENTED;
+        if (!local->ops->set_frag_threshold)
+                tx->flags |= IEEE80211_TX_FRAGMENTED;
 
         /* process and remove the injection radiotap header */
         if (unlikely(info->flags & IEEE80211_TX_INTFL_HAS_RADIOTAP)) {
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 0b6fc92bc0d7..e486286ebf1a 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -1152,6 +1152,9 @@ int ieee80211_reconfig(struct ieee80211_local *local)
         }
         mutex_unlock(&local->sta_mtx);
 
+        /* setup fragmentation threshold */
+        drv_set_frag_threshold(local, hw->wiphy->frag_threshold);
+
         /* setup RTS threshold */
         drv_set_rts_threshold(local, hw->wiphy->rts_threshold);