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[222.152.189.137]) by smtp.gmail.com with ESMTPSA id r13sm8246894pjj.9.2021.07.08.22.47.21 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 08 Jul 2021 22:47:24 -0700 (PDT) Subject: Re: [PATCH RFC v2] m68k: remove get_fs()/set_fs() To: Christoph Hellwig References: <1625708899-29013-1-git-send-email-schmitzmic@gmail.com> <20210708043145.GB17672@lst.de> <38991687-7b33-994b-b7d3-22400872a45a@gmail.com> <20210708045804.GA18249@lst.de> <147ffcbd-f946-bb6c-b7bc-35c0672572ce@gmail.com> <20210708125751.GA11898@lst.de> <21557cf4-e1a7-69c3-7c67-c7d4e5a6fbf7@gmail.com> <20210709042219.GA13558@lst.de> Cc: Linus Torvalds , Geert Uytterhoeven , linux-m68k From: Michael Schmitz Message-ID: <1f4dde5e-2038-f0db-832d-b8dde98a52f8@gmail.com> Date: Fri, 9 Jul 2021 17:47:18 +1200 User-Agent: Mozilla/5.0 (X11; Linux ppc; rv:45.0) Gecko/20100101 Icedove/45.4.0 MIME-Version: 1.0 In-Reply-To: <20210709042219.GA13558@lst.de> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-m68k@vger.kernel.org Hi Christoph, Am 09.07.2021 um 16:22 schrieb Christoph Hellwig: > On Fri, Jul 09, 2021 at 12:31:45PM +1200, Michael Schmitz wrote: >> That patch works fine on a casual test. What you did to >> __constant_copy_to_user() does not appear to matter - but I haven't put the >> system under any kind of stress yet. I'm a little reluctant to do that >> (recovering from a trashed boot disk is a little dicey), I'll probably only >> try that with your changes to __constant_copy_to_user() from commit >> d36105c942e0 backed out. > > As Linus pointed out, small copy_to_user basically doesn't happen as > we have switched all the suspect call sites to just use put_user. Thanks, I missed that. That does explain it then. I see you've put a warning message in set_fc() - let's see whether that triggers on a test run on real hardware. Cheers, Michael > Geert: do you care about __constant_copy_to_user at all, or can we just > kill it (as well as the copy_from_user side)? >