Thread (14 messages) 14 messages, 4 authors, 2021-08-30

Re: [PATCH 2/3] staging: r8188eu: simplify c2h_evt_hdl function

From: Fabio M. De Francesco <hidden>
Date: 2021-08-29 08:52:10
Also in: lkml

On Saturday, August 28, 2021 11:24:52 PM CEST Phillip Potter wrote:
quoted hunk ↗ jump to hunk
Simplify c2h_evt_hdl function by removing majority of its code. The
function always returns _FAIL anyway, due to the wrapper function it
calls always returning _FAIL. For this reason, it is better to just
return _FAIL directly.

Leave the call to c2h_evt_read in place, as without it, event handling
semantics of the driver would be changed, despite nothing actually being
done with the event.

Signed-off-by: Phillip Potter <phil@philpotter.co.uk>
---
 drivers/staging/r8188eu/core/rtw_cmd.c | 21 +++------------------
 1 file changed, 3 insertions(+), 18 deletions(-)
diff --git a/drivers/staging/r8188eu/core/rtw_cmd.c b/drivers/staging/r8188eu/core/rtw_cmd.c
index ce73ac7cf973..b520c6b43c03 100644
--- a/drivers/staging/r8188eu/core/rtw_cmd.c
+++ b/drivers/staging/r8188eu/core/rtw_cmd.c
@@ -1854,27 +1854,12 @@ u8 rtw_c2h_wk_cmd(struct adapter *padapter, u8 *c2h_evt)
 
 static s32 c2h_evt_hdl(struct adapter *adapter, struct c2h_evt_hdr *c2h_evt, c2h_id_filter filter)
 {
-	s32 ret = _FAIL;
 	u8 buf[16];
 
-	if (!c2h_evt) {
-		/* No c2h event in cmd_obj, read c2h event before handling*/
-		if (c2h_evt_read(adapter, buf) == _SUCCESS) {
-			c2h_evt = (struct c2h_evt_hdr *)buf;
Dear Philip,

Not related to your patch, but what kind of odd assignment is it? c2h_evt takes
the address of a local variable and therefore it crashes the kernel whenever
someone decides to dereference it after this function returns and unwinds 
the stack...
+	if (!c2h_evt)
+		c2h_evt_read(adapter, buf);
Having said that, I strongly doubt that this path is ever taken. I didn't check the call
chain, but it may be that the function in never called or, if it is called, it always
has a valid c2h_evt argument. 

Actually I don't mean to suggest something specific. It simply looks odd, so I'd check 
and if this happens to be the case, I'd remove the whole c2h_evt_hdl().

Regards,

Fabio
 
-			if (filter && !filter(c2h_evt->id))
-				goto exit;
-
-			ret = rtw_hal_c2h_handler(adapter, c2h_evt);
-		}
-	} else {
-		if (filter && !filter(c2h_evt->id))
-			goto exit;
-
-		ret = rtw_hal_c2h_handler(adapter, c2h_evt);
-	}
-exit:
-	return ret;
+	return _FAIL;
 }
 
 static void c2h_wk_callback(struct work_struct *work)
-- 
2.31.1


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