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From: Johannes Berg <johannes@sipsolutions.net>
To: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	rkuo <rkuo@codeaurora.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	David Miller <davem@davemloft.net>,
	linux-wireless@vger.kernel.org, netdev <netdev@vger.kernel.org>
Subject: Re: [PATCH] net: mac80211: tx.c: be sure of 'sdata->vif.type' must be NL80211_IFTYPE_AP when be in NL80211_IFTYPE_AP case
Date: Sat, 30 Nov 2013 13:53:33 +0100	[thread overview]
Message-ID: <1385816013.4327.1.camel@jlt4.sipsolutions.net> (raw)
In-Reply-To: <5299D306.7070701@gmail.com> (sfid-20131130_125901_519610_EDA4068E)

On Sat, 2013-11-30 at 19:59 +0800, Chen Gang wrote:
> On 11/29/2013 11:38 PM, Johannes Berg wrote:
> > 
> >> +++ b/net/mac80211/tx.c
> >> @@ -1814,8 +1814,9 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
> >>  			break;
> >>  		/* fall through */
> >>  	case NL80211_IFTYPE_AP:
> >> -		if (sdata->vif.type == NL80211_IFTYPE_AP)
> >> -			chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
> >> +		if (sdata->vif.type != NL80211_IFTYPE_AP)
> >> +			goto fail_rcu;
> >> +		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
> > 
> > This change is completely wrong.
> > 
> 
> Oh, it is.
> 
> Hmm... for me, this work flow still can be implemented with a little
> clearer way (at least it will avoid related warning):
> 
> -------------------------diff begin------------------------------
> 
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index c558b24..7076128 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -1810,14 +1810,14 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff *skb,
>  		if (!chanctx_conf)
>  			goto fail_rcu;
>  		band = chanctx_conf->def.chan->band;
> -		if (sta)
> -			break;
> -		/* fall through */
> +		if (!sta)
> +			goto try_next;
> +		break;
>  	case NL80211_IFTYPE_AP:
> -		if (sdata->vif.type == NL80211_IFTYPE_AP)
> -			chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
> +		chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf);
>  		if (!chanctx_conf)
>  			goto fail_rcu;
> +try_next:

I don't think that's better than the (fairly obvious) fall-through, and
has a pretty odd goto. Also, depending on the compiler, it still knows
the previous case label and doesn't warn.

johannes


  reply	other threads:[~2013-11-30 12:53 UTC|newest]

Thread overview: 52+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-19  4:57 [PATCH] arch: hexagon: Kconfig: add HAVE_DMA_ATTR in Kconfig and remove "linux/dma-mapping.h" from "asm/dma-mapping.h" Chen Gang
2013-11-25  1:19 ` rkuo
2013-11-25  2:39   ` [PATCH 0/2] arch: hexagon: include: asm: add prefix "vm_" for all enum members in "hexagon_vm.h" Chen Gang
2013-11-25  2:40     ` [PATCH 1/2] " Chen Gang
2013-11-25  2:41       ` [PATCH 2/2] arch: hexagon: include: asm: use 'affinity' instead of 'locdis' for __vmintop_affinity() " Chen Gang
2013-11-28  8:51         ` [PATCH v2] arch: hexagon: include: asm: add prefix "hvm[ci]_" for all enum members " Chen Gang
2013-12-06 18:22           ` rkuo
2013-11-26  4:36       ` [PATCH 1/2] arch: hexagon: include: asm: add prefix "vm_" " Chen Gang
2013-11-27  2:29         ` [PATCH] drivers: scsi: scsi_lib.c: add prefix "SCSILIB_" to macro "SP" Chen Gang
2013-12-01 16:17           ` Bart Van Assche
2013-12-02  0:34             ` Chen Gang
2013-12-02  0:49               ` James Bottomley
2013-12-02 10:14                 ` Chen Gang
2013-12-02 21:32                   ` rkuo
2013-12-03 11:42                     ` Chen Gang
2013-12-04  2:42                     ` [PATCH v2] drivers: scsi: scsi_lib.c: use SG_POOL instead of SP Chen Gang
2013-11-27  3:01         ` [PATCH] drivers: staging: ft1000: ft1000-usb: initialize 'status' with STATUS_SUCCESS in request_code_segment() Chen Gang
2013-11-27  9:18           ` Josh Triplett
2013-11-27  9:27             ` Chen Gang
2013-12-04  7:31               ` Chen Gang
2013-11-27  3:17         ` [PATCH] drivers: staging: media: go7007: go7007-usb.c use pr_*() instead of dev_*() before 'go' initialized in go7007_usb_probe() Chen Gang
2013-11-27  3:21           ` Joe Perches
2013-11-27  3:40             ` Chen Gang
2013-11-27  3:48               ` [PATCH v2] " Chen Gang
2013-11-27  4:03                 ` Greg KH
2013-11-27  4:24                   ` Chen Gang
2013-11-27 10:43                     ` Dan Carpenter
2013-11-28  1:47                       ` Chen Gang
2013-11-27  3:40         ` [PATCH] drivers: staging: ft1000: ft1000-usb: ft1000_debug.c: check return value of get_user() in ft1000_ioctl() Chen Gang
2013-11-27  4:53         ` [PATCH] net: mac80211: tx.c: be sure of 'sdata->vif.type' must be NL80211_IFTYPE_AP when be in NL80211_IFTYPE_AP case Chen Gang
2013-11-29 15:38           ` Johannes Berg
2013-11-30 11:59             ` Chen Gang
2013-11-30 12:53               ` Johannes Berg [this message]
2013-11-30 13:50                 ` Chen Gang
2013-11-30 14:02                   ` Chen Gang
2013-11-30 20:08                     ` Johannes Berg
2013-11-30 20:39                       ` Joe Perches
2013-11-30 23:48                         ` Chen Gang
2013-11-30 23:59                           ` Chen Gang
2013-12-01  9:37                           ` Johannes Berg
2013-12-01 11:50                             ` Chen Gang
2013-12-01  9:35                         ` Johannes Berg
2013-12-01 22:38                           ` Joe Perches
2013-12-02  0:45                             ` Chen Gang
2013-12-02 14:48                             ` Johannes Berg
2013-12-04  2:12                               ` Chen Gang
2013-12-04  8:04                                 ` Johannes Berg
2013-12-04  8:41                                   ` Chen Gang
2013-12-04  8:49                                     ` Johannes Berg
2013-12-04  9:00                                       ` Chen Gang
2013-11-27  5:28         ` [PATCH] arch: hexagon: include: uapi: asm: setup.h add swith macro __KERNEL__ Chen Gang
2013-12-06 18:21           ` rkuo

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