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From:   Ivan Safonov <insafonov@gmail.com>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Hariprasad Kelam <hariprasad.kelam@gmail.com>,
        Colin Ian King <colin.king@canonical.com>,
        Dan Carpenter <dan.carpenter@oracle.com>,
        Simran Singhal <singhalsimran0@gmail.com>,
        R Veera Kumar <vkor@vkten.in>,
        Michael Straube <straube.linux@gmail.com>,
        Kees Cook <keescook@chromium.org>,
        Shobhit Kukreti <shobhitkukreti@gmail.com>,
        Nishka Dasgupta <nishkadg.linux@gmail.com>,
        Lukasz Szczesny <luk@wybcz.pl>, devel@driverdev.osuosl.org,
        linux-kernel@vger.kernel.org,
        Larry Finger <Larry.Finger@lwfinger.net>,
        Hans de Goede <hdegoede@redhat.com>,
        Ivan Safonov <insafonov@gmail.com>
Subject: [PATCH] staging:rtl8723bs: eliminate usage of skb_clone after skb allocation fail
Date:   Sat,  2 May 2020 18:19:05 +0300
Message-Id: <20200502151905.43663-1-insafonov@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

The skb allocated when out of memory
is likely to be discarded during subsequent processing.

Signed-off-by: Ivan Safonov <insafonov@gmail.com>
---
 .../staging/rtl8723bs/hal/rtl8723bs_recv.c    | 44 ++++++-------------
 drivers/staging/rtl8723bs/os_dep/recv_linux.c | 19 +++-----
 2 files changed, 19 insertions(+), 44 deletions(-)

diff --git a/drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c b/drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c
index c3051ebaeb78..29c29e2e125b 100644
--- a/drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c
+++ b/drivers/staging/rtl8723bs/hal/rtl8723bs_recv.c
@@ -311,39 +311,21 @@ static void rtl8723bs_recv_tasklet(unsigned long priv)
 				}
 
 				pkt_copy = rtw_skb_alloc(alloc_sz);
-
-				if (pkt_copy) {
-					pkt_copy->dev = padapter->pnetdev;
-					precvframe->u.hdr.pkt = pkt_copy;
-					skb_reserve(pkt_copy, 8 - ((SIZE_PTR)(pkt_copy->data) & 7));/* force pkt_copy->data at 8-byte alignment address */
-					skb_reserve(pkt_copy, shift_sz);/* force ip_hdr at 8-byte alignment address according to shift_sz. */
-					memcpy(pkt_copy->data, (ptr + rx_report_sz + pattrib->shift_sz), skb_len);
-					precvframe->u.hdr.rx_head = pkt_copy->head;
-					precvframe->u.hdr.rx_data = precvframe->u.hdr.rx_tail = pkt_copy->data;
-					precvframe->u.hdr.rx_end = skb_end_pointer(pkt_copy);
-				} else {
-					if ((pattrib->mfrag == 1) && (pattrib->frag_num == 0)) {
-						DBG_8192C("%s: alloc_skb fail, drop frag frame\n", __func__);
-						rtw_free_recvframe(precvframe, &precvpriv->free_recv_queue);
-						break;
-					}
-
-					precvframe->u.hdr.pkt = rtw_skb_clone(precvbuf->pskb);
-					if (precvframe->u.hdr.pkt) {
-						_pkt *pkt_clone = precvframe->u.hdr.pkt;
-
-						pkt_clone->data = ptr + rx_report_sz + pattrib->shift_sz;
-						skb_reset_tail_pointer(pkt_clone);
-						precvframe->u.hdr.rx_head = precvframe->u.hdr.rx_data = precvframe->u.hdr.rx_tail
-							= pkt_clone->data;
-						precvframe->u.hdr.rx_end = pkt_clone->data + skb_len;
-					} else {
-						DBG_8192C("%s: rtw_skb_clone fail\n", __func__);
-						rtw_free_recvframe(precvframe, &precvpriv->free_recv_queue);
-						break;
-					}
+				if (!pkt_copy) {
+					DBG_8192C("%s: alloc_skb fail, drop frame\n", __func__);
+					rtw_free_recvframe(precvframe, &precvpriv->free_recv_queue);
+					break;
 				}
 
+				pkt_copy->dev = padapter->pnetdev;
+				precvframe->u.hdr.pkt = pkt_copy;
+				skb_reserve(pkt_copy, 8 - ((SIZE_PTR)(pkt_copy->data) & 7));/* force pkt_copy->data at 8-byte alignment address */
+				skb_reserve(pkt_copy, shift_sz);/* force ip_hdr at 8-byte alignment address according to shift_sz. */
+				memcpy(pkt_copy->data, (ptr + rx_report_sz + pattrib->shift_sz), skb_len);
+				precvframe->u.hdr.rx_head = pkt_copy->head;
+				precvframe->u.hdr.rx_data = precvframe->u.hdr.rx_tail = pkt_copy->data;
+				precvframe->u.hdr.rx_end = skb_end_pointer(pkt_copy);
+
 				recvframe_put(precvframe, skb_len);
 				/* recvframe_pull(precvframe, drvinfo_sz + RXDESC_SIZE); */
 
diff --git a/drivers/staging/rtl8723bs/os_dep/recv_linux.c b/drivers/staging/rtl8723bs/os_dep/recv_linux.c
index 60c35d92ba29..560221723d70 100644
--- a/drivers/staging/rtl8723bs/os_dep/recv_linux.c
+++ b/drivers/staging/rtl8723bs/os_dep/recv_linux.c
@@ -60,21 +60,14 @@ _pkt *rtw_os_alloc_msdu_pkt(union recv_frame *prframe, u16 nSubframe_Length, u8
 	pattrib = &prframe->u.hdr.attrib;
 
 	sub_skb = rtw_skb_alloc(nSubframe_Length + 12);
-	if (sub_skb) {
-		skb_reserve(sub_skb, 12);
-		skb_put_data(sub_skb, (pdata + ETH_HLEN), nSubframe_Length);
-	} else {
-		sub_skb = rtw_skb_clone(prframe->u.hdr.pkt);
-		if (sub_skb) {
-			sub_skb->data = pdata + ETH_HLEN;
-			sub_skb->len = nSubframe_Length;
-			skb_set_tail_pointer(sub_skb, nSubframe_Length);
-		} else {
-			DBG_871X("%s(): rtw_skb_clone() Fail!!!\n", __func__);
-			return NULL;
-		}
+	if (!sub_skb) {
+		DBG_871X("%s(): rtw_skb_alloc() Fail!!!\n", __func__);
+		return NULL;
 	}
 
+	skb_reserve(sub_skb, 12);
+	skb_put_data(sub_skb, (pdata + ETH_HLEN), nSubframe_Length);
+
 	eth_type = RTW_GET_BE16(&sub_skb->data[6]);
 
 	if (sub_skb->len >= 8 &&
-- 
2.26.2