staging: r8188eu: fix potential memory leak in _rtw_init_xmit_priv()

In _rtw_init_xmit_priv(), there are several error paths for allocation
failures just jump to the `exit` section. However, there is no action
will be performed, so the allocated resources are not properly released,
which leads to various memory leaks.

To properly release them, this patch unifies the error handling code and
several error handling paths are added.
According to the allocation sequence, if the validation fails, it will
jump to its corresponding error tag to release the resources.

Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
Link: https://lore.kernel.org/r/tencent_DB57E4F270F4539485C32B05FDAF8394310A@qq.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/r8188eu/core/rtw_xmit.c

@@ -134,7 +134,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (!pxmitpriv->pallocated_xmitbuf) {
 		res = _FAIL;
-		goto exit;
+		goto free_frame_buf;
 	}
 
 	pxmitpriv->pxmitbuf = (u8 *)ALIGN((size_t)(pxmitpriv->pallocated_xmitbuf), 4);
@@ -156,7 +156,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 			msleep(10);
 			res = rtw_xmit_resource_alloc(padapter, pxmitbuf, (MAX_XMITBUF_SZ + XMITBUF_ALIGN_SZ));
 			if (res == _FAIL)
-				goto exit;
+				goto free_xmitbuf;
 		}
 
 		pxmitbuf->flags = XMIT_VO_QUEUE;
@@ -174,7 +174,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (!pxmitpriv->pallocated_xmit_extbuf) {
 		res = _FAIL;
-		goto exit;
+		goto free_xmitbuf;
 	}
 
 	pxmitpriv->pxmit_extbuf = (u8 *)ALIGN((size_t)(pxmitpriv->pallocated_xmit_extbuf), 4);
@@ -191,7 +191,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 		res = rtw_xmit_resource_alloc(padapter, pxmitbuf, max_xmit_extbuf_size + XMITBUF_ALIGN_SZ);
 		if (res == _FAIL) {
 			res = _FAIL;
-			goto exit;
+			goto free_xmit_extbuf;
 		}
 
 		list_add_tail(&pxmitbuf->list, &pxmitpriv->free_xmit_extbuf_queue.queue);
@@ -202,7 +202,7 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	if (rtw_alloc_hwxmits(padapter)) {
 		res = _FAIL;
-		goto exit;
+		goto free_xmit_extbuf;
 	}
 
 	rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
@@ -226,8 +226,26 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
 
 	rtl8188eu_init_xmit_priv(padapter);
 
-exit:
+	return _SUCCESS;
 
+free_xmit_extbuf:
+	pxmitbuf = (struct xmit_buf *)pxmitpriv->pxmit_extbuf;
+	while (i--) {
+		rtw_xmit_resource_free(padapter, pxmitbuf, (max_xmit_extbuf_size + XMITBUF_ALIGN_SZ));
+		pxmitbuf++;
+	}
+	vfree(pxmitpriv->pallocated_xmit_extbuf);
+	i = NR_XMITBUFF;
+free_xmitbuf:
+	pxmitbuf = (struct xmit_buf *)pxmitpriv->pxmitbuf;
+	while (i--) {
+		rtw_xmit_resource_free(padapter, pxmitbuf, (MAX_XMITBUF_SZ + XMITBUF_ALIGN_SZ));
+		pxmitbuf++;
+	}
+	vfree(pxmitpriv->pallocated_xmitbuf);
+free_frame_buf:
+	vfree(pxmitpriv->pallocated_frame_buf);
+exit:
 	return res;
 }