From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f45.google.com (mail-ed1-f45.google.com [209.85.208.45]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1AEF01366; Sat, 2 Apr 2022 10:13:27 +0000 (UTC) Received: by mail-ed1-f45.google.com with SMTP id h4so5642000edr.3; Sat, 02 Apr 2022 03:13:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=nq7rsHg8A3iBgRJPmTpgXY1OAM+6fX6NYBzTSzTX1C4=; b=CTwZbdYvrj4KAu0xHRfcJUQGyWJaqzAOfCiguc/crzFxDm2B7eKW5F2KudW+/zpD4h ENeIVrF38WevKHfBGdtUAtVLwHbjAlNvHiGllWuMkg3t7SNnyktQ/wfYmk2Iu57V7Hqh p1RVlMCOrWp/kou0x5bp8xAazC2aiox4Gyb15wS0KL8ReMTgj6mC3siHhSbTWB9u6vzp iodgdPSC0x7qOoFuAM5Ls52XjBLpHTZY3glwRBtFswt9TBj6rrawGSKbATE5IroqfN7H GFNKHu9mUNTqTUtf1m6EnqQJGKTFY/iOp4Y73YsDUmiIBparj1N4WCQpByskqMRv4snO me7w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=nq7rsHg8A3iBgRJPmTpgXY1OAM+6fX6NYBzTSzTX1C4=; b=ndyf85c0O5vY2pwVUWwYqljCTd00FtqxU9hE7tF1HcC0XqUjo8t9+kMA9YN4s7eQGg u+Y2P+Qis1/p27XdhyEKqS76kYSqqECndu7MPX1ykGt1D6OT2fO7fuLCMKwkJU6qtWuC LPk2kDMZZi7b/7TSqauYy9WmQ3y8Qihhe215PW76JiJhRK+GCHxW+s8L2CjanLVqrklx 92MPhcE1wXqsMPYh7a8a6O2H5Q1kFDX3KHaUohH8BH1+FatCZ92sOoisD55VniI1Cqn6 sNHYHwL14NQE10xFGKwED9pR9lS6Ptp4BylkexhWmHf2Kn8uH6J0vwi8HPZhx2n44FOO TzLg== X-Gm-Message-State: AOAM533hmMmKg8JWy1zayppL6io/LwnRMk1WYoaTTK5I8SouJSG3Go7F Ahmmh637iX54/y5elwQAEgo= X-Google-Smtp-Source: ABdhPJzqJkyefi7J2cWzB2Ryqz9jNoMNznjyESx9VUbicGy3kNqEj5pQvaHy6jaGftlqgmnLWXAdjg== X-Received: by 2002:a05:6402:13d6:b0:419:2eab:d21 with SMTP id a22-20020a05640213d600b004192eab0d21mr24687793edx.78.1648894405231; Sat, 02 Apr 2022 03:13:25 -0700 (PDT) Received: from leap.localnet (host-95-249-145-232.retail.telecomitalia.it. [95.249.145.232]) by smtp.gmail.com with ESMTPSA id gq12-20020a170906e24c00b006e067c93e1bsm1929807ejb.39.2022.04.02.03.13.22 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 02 Apr 2022 03:13:23 -0700 (PDT) From: "Fabio M. De Francesco" To: Ira Weiny , Greg Kroah-Hartman Cc: Larry Finger , Phillip Potter , linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, outreachy@lists.linux.dev Subject: Re: [PATCH] staging: r8188eu: Remove goto to no-op exit label Date: Sat, 02 Apr 2022 12:13:20 +0200 Message-ID: <1724388.VLH7GnMWUR@leap> In-Reply-To: References: <20220401183513.26222-1-fmdefrancesco@gmail.com> Precedence: bulk X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" On venerd? 1 aprile 2022 22:41:40 CEST Ira Weiny wrote: > On Fri, Apr 01, 2022 at 08:35:13PM +0200, Fabio M. De Francesco wrote: > > In function rtw_free_netdev() there are two "goto" jumps to a no-op exit > > label called "RETURN". Remove the label and return in line. > > Thanks for the patch! However, A good commit message lists the why and what of > a change. I don't see a why for this commit? Yes I forgot the "why" :( I'll rework the commit message for v2. > > FWIW (For what it's worth) I know of a couple of good reasons for this change > but you should get in the habit of putting that in the commit message. Even > for obvious things like this. > > Anyway, I think this patch can stand on it's own with an updated commit > message. However, see below... > > > > > Signed-off-by: Fabio M. De Francesco > > --- > > drivers/staging/r8188eu/os_dep/osdep_service.c | 7 ++----- > > 1 file changed, 2 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/staging/r8188eu/os_dep/osdep_service.c b/drivers/staging/r8188eu/os_dep/osdep_service.c > > index 7a6fcc96081a..d680bfba7f5d 100644 > > --- a/drivers/staging/r8188eu/os_dep/osdep_service.c > > +++ b/drivers/staging/r8188eu/os_dep/osdep_service.c > > @@ -117,18 +117,15 @@ void rtw_free_netdev(struct net_device *netdev) > > struct rtw_netdev_priv_indicator *pnpi; > > > > if (!netdev) > > - goto RETURN; > > + return; Actually this function doesn't need to test for a valid "netdev". There are only two callers of this function (they are in os_dep/usb_intf.c) and they already test the pointer soon before calling rtw_free_netdev(). Therefore, I'll remove the test for a valid "netdev" and (obviously) the code has no more need to return at that point in function. > > > > pnpi = netdev_priv(netdev); > > > > if (!pnpi->priv) > > - goto RETURN; > > + return; I cannot see how pnpi->priv might ever be NULL. Pavel Skripkin made me notice that "in rtw_alloc_etherdev() (I can confirm this information because now I've just read the code), if pnpi->priv allocation fails, then netdev will be just freed.". If "netdev" is already free, this function is never called. Therefore, I'll remove this test too. > This does not look right. If netdev is not NULL why does this function skip > free_netdev()? After the two removals I've talked about above, the code will always call vfree(pnpi->priv) and then free_netdev(netdev). Therefore, the code won't anymore skip free_netdev() and the bug is avoided. > > Fabio could you follow up with Larry and/or Phillip and see why the code does > this? To me it looks like a potential bug. > > Thanks! > Ira > > > > > vfree(pnpi->priv); > > free_netdev(netdev); > > - > > -RETURN: > > - return; > > } > > > > int rtw_change_ifname(struct adapter *padapter, const char *ifname) > > -- > > 2.34.1 > > > This is how I think to rework rtw_free_netdev(): void rtw_free_netdev(struct net_device *netdev) { struct rtw_netdev_priv_indicator *pnpi = netdev_priv(netdev); vfree(pnpi->priv); free_netdev(netdev); } Am I missing something? @Greg: please discard this patch; I'll send another that has the purpose to rework rtw_free_netdev() as I showed above for the purpose to avoid redundant tests and avoid the potential skipping of free_netdev() (as Ira has correctly noted, currently we have a bug). Thanks, Fabio