linux-kernel - Re: [RFC v2 1/1] RTL8712 alignment bug in 3.6 and up on ARMV5

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Message-ID: <20121215194324.GD5032@mwanda>
Date:	Sat, 15 Dec 2012 22:43:24 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Josh Coombs <josh.coombs@...il.com>
Cc:	Andrew Lunn <andrew@...n.ch>, devel@...verdev.osuosl.org,
	florian.c.schilhabel@...glemail.com,
	Russell King - ARM Linux <linux@....linux.org.uk>,
	gregkh@...uxfoundation.org, linux-kernel@...r.kernel.org,
	wlanfae@...ltek.com,
	linux ARM <linux-arm-kernel@...ts.infradead.org>,
	Larry.Finger@...inger.net
Subject: Re: [RFC v2 1/1] RTL8712 alignment bug in 3.6 and up on ARMV5

Thanks for fixing this bug.  Your patch works but it's not the right
way to do it.

The original code here adds 4 to pointers which are currently
aligned instead of leaving them as is.  We have a kernel ALIGN()
macro which works correctly, but actually, it's not needed.

On arm, the pointer returned from kmalloc() is already aligned at
the 8 byte boundary because "#define ARCH_SLAB_MINALIGN 8".  The
original code always adds 4 to the pointer so everything is
misaligned.

Your patch adds another 4 bytes so it is now aligned at the 8 byte
boundary again.  That works, of course, but it's better to remove
the whole mess.

	pstapriv->pallocated_stainfo_buf = kmalloc(sizeof(struct sta_info) * NUM_STA);

Get rid of the ->pstainfo_buf pointer which is only used to store
the "aligned" version of ->pallocated_stainfo_buf.

Please send a version which applies with "git am" and has the proper
sign-off.  Sent it to yourself first.  Save the raw email (including
headers and everything).
	cat raw_email.txt | git am
Type "git log -p" to verify that the commit message looks good.
Then resend it to the list.

Thanks again.  This is a good bugfix.

regards,
dan carpenter

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