From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C10F2C4332B for ; Mon, 8 Mar 2021 14:12:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8C77A65201 for ; Mon, 8 Mar 2021 14:12:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230111AbhCHOM2 (ORCPT ); Mon, 8 Mar 2021 09:12:28 -0500 Received: from mail.kernel.org ([198.145.29.99]:40044 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231307AbhCHOMM (ORCPT ); Mon, 8 Mar 2021 09:12:12 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id D8C6E650F2; Mon, 8 Mar 2021 14:12:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615212732; bh=TpYHSv5nK8/7K9g1DZ6mZmGpQI/dDZxeoiKf7FDZj7k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=s1Trenm8s5+P7MTFrWH3/PL8Ph7ExbOVf3gDt+TPUTnRzOVI1S008+zqRfwmUuu9L zKKVz67Bjgmuf+6vyZr9K/7hIjO2ZtcCeB6vMAtS/g2zzPa5S7mRjaLNpMb+XTUA2X UYCpckQ4JJG7vnCoOAJbHqqYq4GBu0MzzKf5Nym/+T7w7k8EzLRhpLANDETtHbD3kZ qvp5i8eVegFI+ybyq19MCPIjij0lOXDVsKZT36xeO45Ws8N90SIo+ztYlAbbE3ZQhG nKkBffD41siP/MlC7FZoRr13Y/kGIrOh0K7M34uSVBP0AFWUZv0Lleb/Angctd3dsV /YKN+oQvIHfjw== Date: Mon, 8 Mar 2021 14:11:01 +0000 From: Mark Brown To: Lukas Wunner Cc: Jay Fang , linux-spi@vger.kernel.org, huangdaode@huawei.com Subject: Re: [PATCH] spi: Add HiSilicon SPI controller driver support Message-ID: <20210308141101.GC4656@sirena.org.uk> References: <1614599771-33629-1-git-send-email-f.fangjian@huawei.com> <20210301135405.GC4628@sirena.org.uk> <20210307144313.GA15472@wunner.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="eRtJSFbw+EEWtPj3" Content-Disposition: inline In-Reply-To: <20210307144313.GA15472@wunner.de> X-Cookie: Am I SHOPLIFTING? User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org --eRtJSFbw+EEWtPj3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sun, Mar 07, 2021 at 03:43:13PM +0100, Lukas Wunner wrote: > On Mon, Mar 01, 2021 at 01:54:05PM +0000, Mark Brown wrote: > > On Mon, Mar 01, 2021 at 07:56:11PM +0800, Jay Fang wrote: > > > + ret = devm_request_irq(dev, hs->irq, hisi_spi_irq, IRQF_SHARED, > > > + dev_name(dev), master); > > > + if (ret < 0) { > > > + dev_err(dev, "failed to get IRQ=%d, ret=%d\n", hs->irq, ret); > > > + return ret; > > > + } > > This will free the IRQ *after* the controller is unregistered, it's > > better to manually free the interrupt > Transfers may still be ongoing until spi_unregister_controller() returns. > (It's called from devres_release_all() in this case.) Since the IRQ is > presumably necessary to handle those transfers, freeing the IRQ after > unregistering is actually correct. So the code looks fine in principle. Well, it should just time out which is annoying. > However, because the IRQ is requested with IRQF_SHARED, the handler may > be invoked at any time, even after the controller has been unregistered. > It is therefore necessary to quiesce the SPI controller's interrupt on > unregistering and it is also necessary to check in the IRQ handler whether > an interrupt is actually pending (and bail out if not). It's also important and even more of a concern that even if there is a valid interrupt the handler doesn't try to use structures that might have been deallocated before the handler uses it as this controller does, that will segfault which is more serious. --eRtJSFbw+EEWtPj3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmBGMHUACgkQJNaLcl1U h9BKWgf8DT5qM2k5+JsYrmuVeoJbBijnMoT4P90g3dkSSHrfP6+VQdlSTvmLGrRH rtIcIfzuuTKYhJGFapWgE71ZPoIW+G12ZKe0ao0hV6Tbvv92ClaYWV7CEYO0i0o6 PTbpfjmpuEHh1Ld3gXeGbia0Jz/feLq9WCzuGUcRmkj7Nr48grJe1uwoLrAcJ22V KVpOTY6hs0cL14wHFtUOdYaC+0nybDc+chRwLxRBja+xoqQhj8V+1MZFoBU91OOH NmpOPzbaWJmEz4EBNODbxJbO0WaOpew6r313yaPJeEZLpsAqmkRTAxlnsrpqdxwO CSEry5OhUluavwdcMjGHR6U/ZH9tdQ== =iimQ -----END PGP SIGNATURE----- --eRtJSFbw+EEWtPj3--