[PATCH v4] staging: r8188eu: fix a potential memory leak in _rtw_init_cmd_priv()

[xkernel . wang]

From: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>

In _rtw_init_cmd_priv(), if `pcmdpriv->rsp_allocated_buf` is allocated  
in failure, then `pcmdpriv->cmd_allocated_buf` will not be properly 
released. Besides, considering there are only two error paths and the 
first one can directly return, we do not need to implicitly jump to the 
`exit` tag to execute the error handling code.

So this patch added `kfree(pcmdpriv->cmd_allocated_buf);` on the error 
path to release the resource and simplified the return logic of 
_rtw_init_cmd_priv().

Signed-off-by: Xiaoke Wang <xkernel.wang@xxxxxxxxxxx>
---
ChangeLog:
v1->v2: simplify the function.
v2->v3: rebase and recover some whitespace cleanups.
v3->v4: update the description.
 drivers/staging/r8188eu/core/rtw_cmd.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/drivers/staging/r8188eu/core/rtw_cmd.c b/drivers/staging/r8188eu/core/rtw_cmd.c
index 4eeb961..f6653d6 100644
--- a/drivers/staging/r8188eu/core/rtw_cmd.c
+++ b/drivers/staging/r8188eu/core/rtw_cmd.c
@@ -18,8 +18,6 @@ No irqsave is necessary.
 
 static int _rtw_init_cmd_priv(struct cmd_priv *pcmdpriv)
 {
-	int res = _SUCCESS;
-
 	init_completion(&pcmdpriv->enqueue_cmd);
 	/* sema_init(&(pcmdpriv->cmd_done_sema), 0); */
 	init_completion(&pcmdpriv->start_cmd_thread);
@@ -34,27 +32,24 @@ static int _rtw_init_cmd_priv(struct cmd_priv *pcmdpriv)
 	pcmdpriv->cmd_allocated_buf = kzalloc(MAX_CMDSZ + CMDBUFF_ALIGN_SZ,
 					      GFP_KERNEL);
 
-	if (!pcmdpriv->cmd_allocated_buf) {
-		res = _FAIL;
-		goto exit;
-	}
+	if (!pcmdpriv->cmd_allocated_buf)
+		return _FAIL;
 
 	pcmdpriv->cmd_buf = pcmdpriv->cmd_allocated_buf  +  CMDBUFF_ALIGN_SZ - ((size_t)(pcmdpriv->cmd_allocated_buf) & (CMDBUFF_ALIGN_SZ - 1));
 
 	pcmdpriv->rsp_allocated_buf = kzalloc(MAX_RSPSZ + 4, GFP_KERNEL);
 
 	if (!pcmdpriv->rsp_allocated_buf) {
-		res = _FAIL;
-		goto exit;
+		kfree(pcmdpriv->cmd_allocated_buf);
+		return _FAIL;
 	}
 
 	pcmdpriv->rsp_buf = pcmdpriv->rsp_allocated_buf  +  4 - ((size_t)(pcmdpriv->rsp_allocated_buf) & 3);
 
 	pcmdpriv->cmd_done_cnt = 0;
 	pcmdpriv->rsp_cnt = 0;
-exit:
 
-	return res;
+	return _SUCCESS;
 }
 
 static void c2h_wk_callback(struct work_struct *work);
--