brcmfmac: Fix glom_skb leak in brcmf_sdiod_recv_chain

BugLink: https://bugs.launchpad.net/bugs/1810807

[ Upstream commit 5ea59db8 ]

An earlier change to this function (3bdae810) fixed a leak in the
case of an unsuccessful call to brcmf_sdiod_buffrw(). However, the
glom_skb buffer, used for emulating a scattering read, is never used
or referenced after its contents are copied into the destination
buffers, and therefore always needs to be freed by the end of the
function.

Fixes: 3bdae810 ("brcmfmac: Fix glob_skb leak in brcmf_sdiod_recv_chain")
Fixes: a413e39a ("brcmfmac: fix brcmf_sdcard_recv_chain() for host without sg support")
Cc: stable@vger.kernel.org # 4.9.x-
Signed-off-by: Peter S. Housel <housel@acm.org>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Juerg Haefliger <juergh@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

drivers/net/wireless/brcm80211/brcmfmac/bcmsdh.c

@@ -705,7 +705,7 @@ int brcmf_sdiod_recv_pkt(struct brcmf_sdio_dev *sdiodev, struct sk_buff *pkt)
 int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev,
 			   struct sk_buff_head *pktq, uint totlen)
 {
-	struct sk_buff *glom_skb;
+	struct sk_buff *glom_skb = NULL;
 	struct sk_buff *skb;
 	u32 addr = sdiodev->sbwad;
 	int err = 0;
@@ -726,10 +726,8 @@ int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev,
 			return -ENOMEM;
 		err = brcmf_sdiod_buffrw(sdiodev, SDIO_FUNC_2, false, addr,
 					 glom_skb);
-		if (err) {
-			brcmu_pkt_buf_free_skb(glom_skb);
+		if (err)
 			goto done;
-		}
 
 		skb_queue_walk(pktq, skb) {
 			memcpy(skb->data, glom_skb->data, skb->len);
@@ -740,6 +738,7 @@ int brcmf_sdiod_recv_chain(struct brcmf_sdio_dev *sdiodev,
 					    pktq);
 
 done:
+	brcmu_pkt_buf_free_skb(glom_skb);
 	return err;
 }