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Subject: Re: [PATCH] mac80211: Fixing sparse warning at sta_info.c
From: Johannes Berg <johannes@sipsolutions.net>
To: Yogesh Ashok Powar <yogeshp@marvell.com>
Cc: "John W. Linville" <linville@tuxdriver.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	Nishant Sarmukadam <nishants@marvell.com>
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Date: Thu, 15 Dec 2011 09:23:45 +0100
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On Thu, 2011-12-15 at 10:43 +0530, Yogesh Ashok Powar wrote:
> The commit 42624d4913a00219a8fdbb4bafd634d1d843be85
> created following sparse warning
> >net/mac80211/sta_info.c:965:24: warning: incorrect type in assignment (different address spaces)
> >net/mac80211/sta_info.c:965:24:    expected struct tid_ampdu_tx *tid_tx
> >net/mac80211/sta_info.c:965:24:    got struct tid_ampdu_tx [noderef] <asn:4>*<noident>
> 
> Making use of rcu_dereference to fix the problem.

That doesn't fix any problem. It trades the compiler warning for a
runtime warning, so NACK.

You will need something like rcu_dereference_protected() here (although
it's not actually protected, but there's also no need to)

johannes