brcmsmac: handle packet drop during transmit correctly

commit c4dea35e34f5f46e1701156153a09cce429d1ea9 upstream.

The .tx() callback function can drop packets when there is no
space in the DMA fifo. Propagate that information to caller
and make sure the freed sk_buff reference is not accessed.

Reviewed-by: Arend van Spriel <arend@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Signed-off-by: Piotr Haber <phaber@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

4 files changed, 13 insertions, 9 deletions

diff --git a/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c b/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c
index 7d71315116cf..36014bf5df9a 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/mac80211_if.c
@@ -280,8 +280,8 @@ static void brcms_ops_tx(struct ieee80211_hw *hw,
 		kfree_skb(skb);
 		goto done;
 	}
-	brcms_c_sendpkt_mac80211(wl->wlc, skb, hw);
-	tx_info->rate_driver_data[0] = control->sta;
+	if (brcms_c_sendpkt_mac80211(wl->wlc, skb, hw))
+		tx_info->rate_driver_data[0] = control->sta;
  done:
 	spin_unlock_bh(&wl->lock);
 }
diff --git a/drivers/net/wireless/brcm80211/brcmsmac/main.c b/drivers/net/wireless/brcm80211/brcmsmac/main.c
index 75086b37c817..9fb0a4c96b78 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/main.c
+++ b/drivers/net/wireless/brcm80211/brcmsmac/main.c
@@ -6095,7 +6095,7 @@ static bool brcms_c_prec_enq(struct brcms_c_info *wlc, struct pktq *q,
 	return brcms_c_prec_enq_head(wlc, q, pkt, prec, false);
 }
 
-void brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
+bool brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
 		     struct sk_buff *sdu, uint prec)
 {
 	struct brcms_txq_info *qi = wlc->pkt_queue;	/* Check me */
@@ -6110,7 +6110,9 @@ void brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
 		 * packet flooding from mac80211 stack
 		 */
 		brcmu_pkt_buf_free_skb(sdu);
+		return false;
 	}
+	return true;
 }
 
 /*
@@ -7273,7 +7275,7 @@ brcms_c_d11hdrs_mac80211(struct brcms_c_info *wlc, struct ieee80211_hw *hw,
 	return 0;
 }
 
-void brcms_c_sendpkt_mac80211(struct brcms_c_info *wlc, struct sk_buff *sdu,
+bool brcms_c_sendpkt_mac80211(struct brcms_c_info *wlc, struct sk_buff *sdu,
 			      struct ieee80211_hw *hw)
 {
 	u8 prio;
@@ -7288,10 +7290,12 @@ void brcms_c_sendpkt_mac80211(struct brcms_c_info *wlc, struct sk_buff *sdu,
 	prio = ieee80211_is_data(d11_header->frame_control) ? sdu->priority :
 		MAXPRIO;
 	fifo = prio2fifo[prio];
-	if (brcms_c_d11hdrs_mac80211(wlc, hw, sdu, scb, 0, 1, fifo, 0))
-		return;
-	brcms_c_txq_enq(wlc, scb, sdu, BRCMS_PRIO_TO_PREC(prio));
+	brcms_c_d11hdrs_mac80211(wlc, hw, sdu, scb, 0, 1, fifo, 0);
+	if (!brcms_c_txq_enq(wlc, scb, sdu, BRCMS_PRIO_TO_PREC(prio)))
+		return false;
 	brcms_c_send_q(wlc);
+
+	return true;
 }
 
 void brcms_c_send_q(struct brcms_c_info *wlc)
diff --git a/drivers/net/wireless/brcm80211/brcmsmac/main.h b/drivers/net/wireless/brcm80211/brcmsmac/main.h
index 8debc74c54e1..b44725c0c23d 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/main.h
+++ b/drivers/net/wireless/brcm80211/brcmsmac/main.h
@@ -642,7 +642,7 @@ extern void brcms_c_txfifo(struct brcms_c_info *wlc, uint fifo,
 			   bool commit, s8 txpktpend);
 extern void brcms_c_txfifo_complete(struct brcms_c_info *wlc, uint fifo,
 				    s8 txpktpend);
-extern void brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
+extern bool brcms_c_txq_enq(struct brcms_c_info *wlc, struct scb *scb,
 			    struct sk_buff *sdu, uint prec);
 extern void brcms_c_print_txstatus(struct tx_status *txs);
 extern int brcms_b_xmtfifo_sz_get(struct brcms_hardware *wlc_hw, uint fifo,
diff --git a/drivers/net/wireless/brcm80211/brcmsmac/pub.h b/drivers/net/wireless/brcm80211/brcmsmac/pub.h
index 5855f4fd16dc..bfa26306d27f 100644
--- a/drivers/net/wireless/brcm80211/brcmsmac/pub.h
+++ b/drivers/net/wireless/brcm80211/brcmsmac/pub.h
@@ -321,7 +321,7 @@ extern void brcms_c_intrsrestore(struct brcms_c_info *wlc, u32 macintmask);
 extern bool brcms_c_intrsupd(struct brcms_c_info *wlc);
 extern bool brcms_c_isr(struct brcms_c_info *wlc, bool *wantdpc);
 extern bool brcms_c_dpc(struct brcms_c_info *wlc, bool bounded);
-extern void brcms_c_sendpkt_mac80211(struct brcms_c_info *wlc,
+extern bool brcms_c_sendpkt_mac80211(struct brcms_c_info *wlc,
 				     struct sk_buff *sdu,
 				     struct ieee80211_hw *hw);
 extern bool brcms_c_aggregatable(struct brcms_c_info *wlc, u8 tid);