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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23793C433F5 for ; Sat, 23 Apr 2022 14:45:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229812AbiDWOsK (ORCPT ); Sat, 23 Apr 2022 10:48:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50434 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229468AbiDWOsJ (ORCPT ); Sat, 23 Apr 2022 10:48:09 -0400 Received: from mail-pl1-x636.google.com (mail-pl1-x636.google.com [IPv6:2607:f8b0:4864:20::636]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B9711E1F for ; Sat, 23 Apr 2022 07:45:11 -0700 (PDT) Received: by mail-pl1-x636.google.com with SMTP id c23so17167489plo.0 for ; Sat, 23 Apr 2022 07:45:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=v5FxqibB6lrBSfM5RHY6cGUOYEFPWbPTw3YyYjEAfbQ=; b=xJuYvvFIBtH1IeO79+DHJTgR1fwDmXMJ41EyXP3EY6AKpSoHPPHtsbZQUmhfTSBTlj e1+ZHJX7cE8KjIRNvLfX7w+ZUPtgepCCONWQBQ8MPXz9XW+5lASpekk8JW3/IOA+SlpS QH2GYdwGRceYdLmx7bUwqv8uJyLSr9y6EMwcm2KQLJusjyAd4mljavIGft4JXw7u6FHP 391iP934qJ0sgBrPXFNqJHdDDp0MiIZECD+28BY6f7N0eVzfYY/teI+Z096jf/rDdL6e hSY2bB/gRYRGEP+bXDZfftaljJOzrazc5Oo6aXRLLloomhxUP/w1GqmB6whe5k1T8Jpm Zirg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=v5FxqibB6lrBSfM5RHY6cGUOYEFPWbPTw3YyYjEAfbQ=; b=NZjaZUKZLrN+cI38FxWa3Fc2kSLQL7NxatZFsqNvNf8+lL2QTxJccsHNtT/yJhfXmw +74ePTiVPfSRXWNJEPUwy5gBB/dp/uZtqaZnOBMsVpakrlg2xb5DQAiMsXdqh1Qq5LGX Hx+YcImN75w0Z5WJ2qNHW7JZ5C8vU2hJcQE62YLFK+k5qnuAyi2rNc7Qycm1H3YkxH32 5zymkgvmel31U+ZF/zls8YDoFmXxSRUk0k9yubYMvHK70VrELLGQZ2SkSGVAKQ/cHa4A SiYSxSKtDK3dne5+dLMRQmX662+ikFCj3LivB+AFfYKj44rRR7AkJzG7o/ez1CADMZHC tsVg== X-Gm-Message-State: AOAM530CmDhsm/e5ydo8sVP0RkhyyBAqZ0K65jA4Zy1NG4IhgZ/65DBl 6nRHVDmdHRnG1MkGzPxSvbpc X-Google-Smtp-Source: ABdhPJzkITaG3M4Hac9FG/Ta+tKPeSf3Xn02HSElnQKPpvX4qD4a7NHj5NfpTV52Ictebf4+9pwF9Q== X-Received: by 2002:a17:903:31d1:b0:159:804:e852 with SMTP id v17-20020a17090331d100b001590804e852mr9419855ple.19.1650725111227; Sat, 23 Apr 2022 07:45:11 -0700 (PDT) Received: from thinkpad ([117.207.28.196]) by smtp.gmail.com with ESMTPSA id x36-20020a634a24000000b0039cc6fff510sm5089396pga.58.2022.04.23.07.45.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 23 Apr 2022 07:45:10 -0700 (PDT) Date: Sat, 23 Apr 2022 20:15:02 +0530 From: Manivannan Sadhasivam To: Serge Semin Cc: Serge Semin , Gustavo Pimentel , Vinod Koul , Jingoo Han , Bjorn Helgaas , Frank Li , Alexey Malahov , Pavel Parkhomenko , Lorenzo Pieralisi , Rob Herring , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , linux-pci@vger.kernel.org, dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 24/25] dmaengine: dw-edma: Skip cleanup procedure if no private data found Message-ID: <20220423144502.GS374560@thinkpad> References: <20220324014836.19149-1-Sergey.Semin@baikalelectronics.ru> <20220324014836.19149-25-Sergey.Semin@baikalelectronics.ru> <20220325181503.GB12218@thinkpad> <20220418134833.awogzzfq745mc5dm@mobilestation> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220418134833.awogzzfq745mc5dm@mobilestation> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Mon, Apr 18, 2022 at 04:48:33PM +0300, Serge Semin wrote: > On Fri, Mar 25, 2022 at 11:45:03PM +0530, Manivannan Sadhasivam wrote: > > On Thu, Mar 24, 2022 at 04:48:35AM +0300, Serge Semin wrote: > > > DW eDMA driver private data is preserved in the passed DW eDMA chip info > > > structure. If either probe procedure failed or for some reason the passed > > > info object doesn't have private data pointer initialized we need to halt > > > the DMA device cleanup procedure in order to prevent possible system > > > crashes. > > > > > > > > How come remove() could happen when probe() failed? If you hit this issue then > > something else is utterly going wrong. > > It fully depends on the DW eDMA client driver implementation, which > can't and in general shouldn't be guessed. But what must be done in > the DW eDMA driver is a protection against the invalid data being > passed to the exported API methods. That wrong situation must be > detected and handled in the API user code. It's much easier to do by > having an error code returned from the dw_edma_remove() method than > catching random system crashes. > Even though I don't see any practical issue, I'm fine with this. Thanks, Mani > -Sergey > > > > > Thanks, > > Mani > > > > > Signed-off-by: Serge Semin > > > --- > > > drivers/dma/dw-edma/dw-edma-core.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c > > > index ca5cd7c99571..b932682a8ba8 100644 > > > --- a/drivers/dma/dw-edma/dw-edma-core.c > > > +++ b/drivers/dma/dw-edma/dw-edma-core.c > > > @@ -1030,6 +1030,10 @@ int dw_edma_remove(struct dw_edma_chip *chip) > > > struct dw_edma *dw = chip->dw; > > > int i; > > > > > > + /* Skip removal if no private data found */ > > > + if (!dw) > > > + return -ENODEV; > > > + > > > /* Disable eDMA */ > > > dw_edma_v0_core_off(dw); > > > > > > -- > > > 2.35.1 > > >