From: Davidlohr Bueso <dave@stgolabs.net>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, Davidlohr Bueso <dbueso@suse.de>
Subject: Re: [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE
Date: Sun, 20 Nov 2016 08:09:40 -0800 [thread overview]
Message-ID: <20161120160940.GA31288@linux-80c1.suse> (raw)
In-Reply-To: <20161120093932.GA21152@kroah.com>
Hi Greg!
On Sun, 20 Nov 2016, Greg KH wrote:
>On Sat, Nov 19, 2016 at 11:54:25AM -0800, Davidlohr Bueso wrote:
>> With the new standardized functions, we can replace all ACCESS_ONCE()
>> calls across relevant drivers/usb/.
>>
>> ACCESS_ONCE() does not work reliably on non-scalar types. For example
>> gcc 4.6 and 4.7 might remove the volatile tag for such accesses during
>> the SRA (scalar replacement of aggregates) step:
>>
>> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145
>>
>> Update the new calls regardless of if it is a scalar type, this is
>> cleaner than having three alternatives.
>>
>> Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
>
>Nit, this doesn't match your From: line :(
That's on purpose, and all my patches are the same.
>If this is the case, why not just replacing the define for ACCESS_ONCE()
>with READ_ONCE() and then go back and just do a search/replace for the
>whole kernel all at once?
So that we don't have three variants; the idea is to eventually
get rid of ACCESS_ONCE entirely.
>
>Or just send Linus a patch for this all at once after -rc1 is out?
No rush, whenever you see fit.
Thanks,
Davidlohr
next prev parent reply other threads:[~2016-11-20 16:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-19 19:54 [PATCH] drivers/usb: use READ_ONCE instead of deprecated ACCESS_ONCE Davidlohr Bueso
2016-11-20 9:39 ` Greg KH
2016-11-20 12:11 ` Mark Rutland
2016-11-20 16:09 ` Davidlohr Bueso [this message]
2016-11-21 7:15 ` Greg KH
2016-11-29 19:24 ` Greg KH
2016-11-30 13:50 ` [PATCH v2] " Davidlohr Bueso
2016-11-30 14:23 ` Greg KH
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