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Mon, 13 Jul 2020 10:27:24 +0800 Message-ID: <1594607245.22878.8.camel@mtkswgap22> Subject: Re: [PATCH v3] scsi: ufs: Cleanup completed request without interrupt notification From: Stanley Chu To: Bart Van Assche CC: , , , , , , , , , , , , , , , , , Date: Mon, 13 Jul 2020 10:27:25 +0800 In-Reply-To: <3d509c4b-d66d-2a4a-5fbd-a50a0610ad31@acm.org> References: <20200706132113.21096-1-stanley.chu@mediatek.com> <3d509c4b-d66d-2a4a-5fbd-a50a0610ad31@acm.org> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: 69731E3067A72BEFA2FBAE86A43C91635FEE4B1E3E5A14E4DECC1E66CD00A30D2000:8 X-MTK: N Content-Transfer-Encoding: base64 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org SGkgQmFydCBhbmQgQXZyaSwNCg0KT24gU3VuLCAyMDIwLTA3LTEyIGF0IDE4OjM5IC0wNzAwLCBC YXJ0IFZhbiBBc3NjaGUgd3JvdGU6DQo+IE9uIDIwMjAtMDctMDYgMDY6MjEsIFN0YW5sZXkgQ2h1 IHdyb3RlOg0KPiA+IElmIHNvbWVob3cgbm8gaW50ZXJydXB0IG5vdGlmaWNhdGlvbiBpcyByYWlz ZWQgZm9yIGEgY29tcGxldGVkIHJlcXVlc3QNCj4gPiBhbmQgaXRzIGRvb3JiZWxsIGJpdCBpcyBj bGVhcmVkIGJ5IGhvc3QsIFVGUyBkcml2ZXIgbmVlZHMgdG8gY2xlYW51cA0KPiA+IGl0cyBvdXRz dGFuZGluZyBiaXQgaW4gdWZzaGNkX2Fib3J0KCkuDQo+IA0KPiBIb3cgaXMgaXQgcG9zc2libGUg dGhhdCBubyBpbnRlcnJ1cHQgbm90aWZpY2F0aW9uIGlzIHJhaXNlZCBmb3IgYSBjb21wbGV0ZWQN Cj4gcmVxdWVzdD8gSXMgdGhpcyB0aGUgcmVzdWx0IG9mIGEgaGFyZHdhcmUgc2hvcnRjb21pbmcg b3IgcmF0aGVyIHRoZSByZXN1bHQNCj4gb2YgaG93IHRoZSBVRlMgZHJpdmVyIHdvcmtzPyBJbiB0 aGUgbGF0dGVyIGNhc2UsIGlzIHRoaXMgcGF0Y2ggcGVyaGFwcyBhDQo+IHdvcmthcm91bmQ/IElm IHNvLCBoYXMgaXQgYmVlbiBjb25zaWRlcmVkIHRvIGZpeCB0aGUgcm9vdCBjYXVzZSBpbnN0ZWFk IG9mDQo+IGltcGxlbWVudGluZyBhIHdvcmthcm91bmQ/DQoNCkFjdHVhbGx5IHRoaXMgZmFpbCBp cyB0cmlnZ2VyZWQgYnkgImVycm9yIGluamVjdGlvbiIgdG8gcHJvZHVjZSBhDQpjb21tYW5kIHRp bWVvdXQgZXZlbnQgZm9yIGNoZWNraW5nIGlmIGFueXRoaW5nIGNhbiBiZSBpbXByb3ZlZCBvciBm aXhlZC4NCg0KSSBhZ3JlZSB0aGF0ICJubyBpbnRlcnJ1cHQgbm90aWZpY2F0aW9uIiBtYXkgYmUg c29tZXRoaW5nIHdyb25nIGluDQpoYXJkd2FyZSBhbmQgdGhlIHJvb3QgY2F1c2Ugc2hhbGwgYmUg Zml4ZWQgaW4gdGhlIGhpZ2hlc3QgcHJpb3JpdHkuDQpIb3dldmVyIGZyb20gdGhpcyBpbmplY3Rp b24sIHdlIGZvdW5kIHVmc2hjZF9hYm9ydCgpIGluZGVlZCBoYXMgYSBkZWZlY3QNCmZsb3cgZm9y IGEgY29ybmVyIGNhc2UsIHNvIHdlIGFyZSBsb29raW5nIGZvciB0aGUgc29sdXRpb24gdG8gZml4 IHRoZQ0KImhvbGUiLg0KDQpXaGF0IHdvdWxkIHlvdSB0aGluayBpZiBMaW51eCBkcml2ZXIgc2hh bGwgY29uc2lkZXIgdGhpcyBjYXNlPyBJZiB0aGlzDQppcyBub3QgbmVjZXNzYXJ5LCBJIHdvdWxk IGRyb3AgdGhpcyBwYXRjaCA6ICkNCg0KVGhhbmtzIGEgbG90LA0KU3RhbmxleSBDaHUNCg0KPiAN Cj4gSW4gc2VjdGlvbiA3LjIuMyBvZiB0aGUgVUZTIHNwZWNpZmljYXRpb24gSSBmb3VuZCB0aGUg Zm9sbG93aW5nIGFib3V0IGhvdw0KPiB0byBwcm9jZXNzIHJlcXVlc3QgY29tcGxldGlvbnM6ICJT b2Z0d2FyZSBkZXRlcm1pbmVzIGlmIG5ldyBUUnMgaGF2ZQ0KPiBjb21wbGV0ZWQgc2luY2Ugc3Rl cCAjMiwgYnkgcmVwZWF0aW5nIG9uZSBvZiB0aGUgdHdvIG1ldGhvZHMgZGVzY3JpYmVkIGluDQo+ IHN0ZXAgIzIuIElmIG5ldyBUUnMgaGF2ZSBjb21wbGV0ZWQsIHNvZnR3YXJlIHJlcGVhdHMgdGhl IHNlcXVlbmNlIGZyb20gc3RlcA0KPiAjMy4iIElzIHN1Y2ggYSBsb29wIHBlcmhhcHMgbWlzc2lu ZyBmcm9tIHRoZSBMaW51eCBVRlMgZHJpdmVyPw0KPiANCj4gVGhhbmtzLA0KPiANCj4gQmFydC4N Cg0K 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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_SANE_2 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 19FDAC433E2 for ; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org Hi Bart and Avri, On Sun, 2020-07-12 at 18:39 -0700, Bart Van Assche wrote: > On 2020-07-06 06:21, Stanley Chu wrote: > > If somehow no interrupt notification is raised for a completed request > > and its doorbell bit is cleared by host, UFS driver needs to cleanup > > its outstanding bit in ufshcd_abort(). > > How is it possible that no interrupt notification is raised for a completed > request? Is this the result of a hardware shortcoming or rather the result > of how the UFS driver works? In the latter case, is this patch perhaps a > workaround? If so, has it been considered to fix the root cause instead of > implementing a workaround? Actually this fail is triggered by "error injection" to produce a command timeout event for checking if anything can be improved or fixed. I agree that "no interrupt notification" may be something wrong in hardware and the root cause shall be fixed in the highest priority. However from this injection, we found ufshcd_abort() indeed has a defect flow for a corner case, so we are looking for the solution to fix the "hole". What would you think if Linux driver shall consider this case? If this is not necessary, I would drop this patch : ) Thanks a lot, Stanley Chu > > In section 7.2.3 of the UFS specification I found the following about how > to process request completions: "Software determines if new TRs have > completed since step #2, by repeating one of the two methods described in > step #2. If new TRs have completed, software repeats the sequence from step > #3." Is such a loop perhaps missing from the Linux UFS driver? > > Thanks, > > Bart. _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek 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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,URIBL_BLOCKED,USER_AGENT_SANE_2 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 F26BCC433E0 for ; Mon, 13 Jul 2020 02:29:08 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C08AB2068F for ; 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bh=vdpX6QOZNKEgVnpAN4JmKDJp7I0M4aDpvfzDjmiNtpI=; b=f/TDqbf7PfrTMQRadRomIUVqOt1l3uynOLQsPGuTdTmvEiR+7CJP8yl5VeroAMqR28i8GqNUfLSEsO/3MjDu9aS3HzH+ms9Ktl72wHReX1eFkn6k8x0YdyMqvJ4WMY+sbDh8hhKBeVr2l5f+bbbAH63a4qgVz1HR+xR4fOBgpLg=; X-UUID: 278e9e934fa44e05b096afc311f79438-20200712 Received: from mtkcas67.mediatek.inc [(172.29.193.45)] by mailgw01.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLS) with ESMTP id 180011289; Sun, 12 Jul 2020 18:27:25 -0800 Received: from MTKMBS02N2.mediatek.inc (172.21.101.101) by MTKMBS62DR.mediatek.inc (172.29.94.18) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Sun, 12 Jul 2020 19:27:27 -0700 Received: from mtkcas07.mediatek.inc (172.21.101.84) by mtkmbs02n2.mediatek.inc (172.21.101.101) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Mon, 13 Jul 2020 10:27:24 +0800 Received: from [172.21.77.33] (172.21.77.33) by mtkcas07.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Mon, 13 Jul 2020 10:27:24 +0800 Message-ID: <1594607245.22878.8.camel@mtkswgap22> Subject: Re: [PATCH v3] scsi: ufs: Cleanup completed request without interrupt notification From: Stanley Chu To: Bart Van Assche Date: Mon, 13 Jul 2020 10:27:25 +0800 In-Reply-To: <3d509c4b-d66d-2a4a-5fbd-a50a0610ad31@acm.org> References: <20200706132113.21096-1-stanley.chu@mediatek.com> <3d509c4b-d66d-2a4a-5fbd-a50a0610ad31@acm.org> X-Mailer: Evolution 3.2.3-0ubuntu6 MIME-Version: 1.0 X-TM-SNTS-SMTP: 69731E3067A72BEFA2FBAE86A43C91635FEE4B1E3E5A14E4DECC1E66CD00A30D2000:8 X-MTK: N X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200712_222736_347958_8B344129 X-CRM114-Status: GOOD ( 17.44 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-scsi@vger.kernel.org, martin.petersen@oracle.com, andy.teng@mediatek.com, jejb@linux.ibm.com, chun-hung.wu@mediatek.com, kuohong.wang@mediatek.com, linux-kernel@vger.kernel.org, avri.altman@wdc.com, cang@codeaurora.org, linux-mediatek@lists.infradead.org, peter.wang@mediatek.com, alim.akhtar@samsung.com, matthias.bgg@gmail.com, asutoshd@codeaurora.org, chaotian.jing@mediatek.com, cc.chou@mediatek.com, linux-arm-kernel@lists.infradead.org, beanhuo@micron.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Bart and Avri, On Sun, 2020-07-12 at 18:39 -0700, Bart Van Assche wrote: > On 2020-07-06 06:21, Stanley Chu wrote: > > If somehow no interrupt notification is raised for a completed request > > and its doorbell bit is cleared by host, UFS driver needs to cleanup > > its outstanding bit in ufshcd_abort(). > > How is it possible that no interrupt notification is raised for a completed > request? Is this the result of a hardware shortcoming or rather the result > of how the UFS driver works? In the latter case, is this patch perhaps a > workaround? If so, has it been considered to fix the root cause instead of > implementing a workaround? Actually this fail is triggered by "error injection" to produce a command timeout event for checking if anything can be improved or fixed. I agree that "no interrupt notification" may be something wrong in hardware and the root cause shall be fixed in the highest priority. However from this injection, we found ufshcd_abort() indeed has a defect flow for a corner case, so we are looking for the solution to fix the "hole". What would you think if Linux driver shall consider this case? If this is not necessary, I would drop this patch : ) Thanks a lot, Stanley Chu > > In section 7.2.3 of the UFS specification I found the following about how > to process request completions: "Software determines if new TRs have > completed since step #2, by repeating one of the two methods described in > step #2. If new TRs have completed, software repeats the sequence from step > #3." Is such a loop perhaps missing from the Linux UFS driver? > > Thanks, > > Bart. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel