From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DCF1D29415 for ; Tue, 31 Dec 2024 18:13:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735668818; cv=none; b=OirnROfg2oFVLlYH4g/rs9pJhNXE/WyY4HSNLE9elFm1xqa+1e/zGrF+HN5mlsWqRG0SdEOZAveyjp7Kno8ouPCJKSClMnqoVRyDefLwB7GbC8JN+Kn4nRXR69SB7QoJl+FN6KidZG/YofXRpMY7WdprjZMj52vlF7h8j9UjUrk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1735668818; c=relaxed/simple; bh=kfVA9Fw+YAUQ75SJrC7MRF1gZanYOSfE6nQjpjVx+dM=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=aWAsAh4DC+puv6jPXvDVtVF1TwBUwfzyzdLaGHGKs2zJVbaiSfY0dK06gTKwKcaENblNcwZoMS3ca8ni7JlpZQClThvOiHFm2T1RzfSohOYHXcJSCEVSzCRK5nGdDiX+MDLr5zQe8eZAb603iZ9/9zFPYoJm9OTRPFBHhNWGk68= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RbwIvcTB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RbwIvcTB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id A5E62C4CED2; Tue, 31 Dec 2024 18:13:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1735668817; bh=kfVA9Fw+YAUQ75SJrC7MRF1gZanYOSfE6nQjpjVx+dM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=RbwIvcTB1J/tsFtrwC3bM/PZFqsQAALjBPcwFoAxiToR42R6xo3PO0CnKzTfcQwd1 D68aQoz8pK3IlbRSCc1j/2jL04Rh3jeNRGRvy6vogmamljiTgv5GsV7wpqIV5BAL8W Z4eBRzLpxShI23AJ4dqQVs515NwPe+D/jAAzUvlAKhUpEF8ZxTouUnFUGLCf/k90LC Oby2P1qo/PlBUqWm6kgtM3E5/isvdcXyfxKMqYHAZdvcGWRcMXPEq37xPQkpHr/VfC o7pXqrw2XqApZLTQfSz3OFBQ30HEWsdYXm4NyUfNddMEKTA1FxDLvKnqMXNSFOeZ5+ 9P0QwXG+r21gA== Date: Tue, 31 Dec 2024 19:13:33 +0100 From: Niklas Cassel To: Manivannan Sadhasivam Cc: Jingoo Han , Lorenzo Pieralisi , Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= , Rob Herring , Bjorn Helgaas , Damien Le Moal , linux-pci@vger.kernel.org Subject: Re: [PATCH] PCI: dwc: Reject a negative nr_irqs value in dw_pcie_edma_irq_verify() Message-ID: References: <20241220072328.351329-2-cassel@kernel.org> <20241231155158.5edodo2r5zar3tfe@thinkpad> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241231155158.5edodo2r5zar3tfe@thinkpad> On Tue, Dec 31, 2024 at 09:21:58PM +0530, Manivannan Sadhasivam wrote: > On Fri, Dec 20, 2024 at 08:23:29AM +0100, Niklas Cassel wrote: > > Platforms that do not have (one or more) dedicated IRQs for the eDMA > > need to set nr_irqs to a non-zero value in their DWC glue driver. > > > > Platforms that do have (one or more) dedicated IRQs do not need to > > initialize nr_irqs. DWC common code will automatically set nr_irqs. > > > > Since a glue driver can initialize nr_irqs, dw_pcie_edma_irq_verify() > > should verify that nr_irqs, if non-zero, is a valid value. Thus, add a > > check in dw_pcie_edma_irq_verify() to reject a negative nr_irqs value. > > > > Why can't we make dw_edma_chip::nr_irqs unsigned? dw_edma is defined in drivers/dma/dw-edma/dw-edma-core.h in struct dw_edma. struct dw_pcie (defined in drivers/pci/controller/dwc/pcie-designware.h) simply has a struct dw_edma as a struct member. If you bounce on nr_irqs in: drivers/dma/dw-edma/dw-edma-core.c and in drivers/dma/dw-edma/dw-edma-pcie.c you can see that this driver uses signed int for this everywhere. I didn't feel like refactoring a whole DMA driver. dw_pcie_edma_irq_verify() is supposed to verify that nr_irqs is either initialized to a valid value by a DWC PCIe glue driver, or that common code initializes it. If nr_irqs is initialized by a glue driver && "pci->edma.nr_irqs != ch_cnt", dw_pcie_edma_irq_verify() returns error and avoids calling dw_edma_probe(), thus it made sense for dw_pcie_edma_irq_verify() to also return error on negative nr_irqs. Kind regards, Niklas