From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753335AbbJSO1D (ORCPT ); Mon, 19 Oct 2015 10:27:03 -0400 Received: from mout.kundenserver.de ([212.227.126.187]:51587 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751386AbbJSO1A (ORCPT ); Mon, 19 Oct 2015 10:27:00 -0400 From: Arnd Bergmann To: John Garry Cc: James.Bottomley@hansenpartnership.com, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linuxarm@huawei.com, zhangfei.gao@linaro.org, linux-scsi@vger.kernel.org, xuwei5@hisilicon.com, john.garry2@mail.dcu.ie, hare@suse.de Subject: Re: [PATCH 13/25] scsi: hisi_sas: add path from phyup irq to SAS framework Date: Mon, 19 Oct 2015 16:26:38 +0200 Message-ID: <4269975.xfCo9ut8KK@wuerfel> User-Agent: KMail/4.11.5 (Linux/3.16.0-10-generic; KDE/4.11.5; x86_64; ; ) In-Reply-To: <5624FA23.1050502@huawei.com> References: <1444663237-238302-1-git-send-email-john.garry@huawei.com> <6858991.h0xpYFqkjM@wuerfel> <5624FA23.1050502@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Provags-ID: V03:K0:ehrUHWQRR7W32ENLAyaRqZyZpvaiUnFCbRlBs6tHNFozOXTO1Qt 8DFpUJRImflS2ldlmQ9ZMv3OHnH0Jre7bpbdh95xpX6CACXrVTqub2sXv7xBD+tZNoJjxTy 1qDN34keyKIuarpCNYZGlxQHbx35aVMF+0YzgQ08KmwJyU69UHogLVaBXNFrUXk0Nfm48ow OOSnYjdAJFLzvLgCN8L6A== X-UI-Out-Filterresults: notjunk:1;V01:K0:t8K93HbkhBc=:qD3ydPoGYSw8O3hoV4+IxG RicJqBT8vHmpoU366BtO81ygGO+jgjUF+IsPraYhTmRyjG59hHDl3RMQDtriHM+4Xa8tj8y5g j1SvlH803VMJqwtJD3A5gdBkOFRuJrpp7bVS3ezgXS+GSKtC69nd60Ne9tDaGxA2qPaXO9bYC GrtVwry737NE7dQng+M6p6sSbjseBzm5PjEwYM0qGkmlc2kzGEcajEZddF/OP/cwZ6LmYxxPN VvUEtZ9VrdlogPtXjdI7muvEtKlKNVZhRJ9Vlvl2xhXHQX3gAWnj+YahuWZ2sdCAL1ixDcNlX 2FsJ91vWYpSL1+FFxvdtMg0bTbrmEHJw1RsGYGQq+Uktw0lFSfK5c+WPtGTFTY5+aiKXZJWFI dZmlezEloGBM0kmL67awnMssEfGb8hTXpncFsRYeyagEMfwXhHaNnnGPjdgjQVHPLYeUiyPY2 /AaqpLkWlGnrkWxQDV/0XHtzS2m57KXy8edQxaBMOZTydbBbfdJWtAXYd5tsY60zoHN7frvpU zLwHpd8C0LMDVRni0rJ+fuW+l2V8BnJCN+4bVJetGokzQ4j0qSIsUap/i1cawIKc4geuFZm+d YQyPzrRXkg9MjKB507M7EbrJcwT3yTQObAciqZFB3VeIqQ0/aZs7UP20ziOzykWcElI0iCrqU 5NTRbaxSM8Nbx/Sas1omLugsvFuuX2Y4HUC/NdLQ4S4J3pM3Ct5EKktLWjmnGmryDxwcQKFXx GIvED2L7enstqhEG Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 19 October 2015 15:11:47 John Garry wrote: > On 16/10/2015 14:36, Arnd Bergmann wrote: > > On Friday 16 October 2015 14:29:55 John Garry wrote: > >> > >> It could be considered. > >> > >> A potential issue I see is with hisi_sas_control_phy() for > >> PHY_FUNC_HARD_RESET: this allocates a hisi_sas_wq struct and processes > >> the reset in the queue work. When we re-enable the phy for the reset, > >> the phyup irq will want to use the same hisi_sas_wq struct which may be > >> in use. > >> > >> hisi_sas_control_phy() is added in 23/35. > > > > I'd have to review more closely, but I think that's fine, as this > > is how most work queues are used: you can queue the same function > > multiple times, and it's guaranteed to run at least once after > > the last queue, so if you queue it while it's already running, > > it will be called again, otherwise it won't. > > > In the scenario I described the issue is not that the second call to > queue the work function is lost. The problem is that when we setup the > second call we may overwrite elements of the phy's hisi_sas_wq struct > which may be still being referenced in the work function for the first call. Do you mean these members? > + wq->event = PHYUP; > + wq->hisi_hba = hisi_hba; > + wq->phy_no = phy_no; Sorry for being unclear, I implied getting rid of them, by having a work queue per phy. You can create a structure for each phy like struct hisi_sas_phy { struct hisi_sas *dev; /* pointer to the device */ unsigned int phy_no; struct work_struct phyup_work; }; There are probably other things you can put into the same structure. When the phy is brought up, you then just start the phyup work for that phy, which can retrieve its hisi_sas_phy structure from the work_struct pointer, and from there get to the device. Arnd