From: Christoph Hellwig <hch@lst.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rafael@kernel.org>,
linux-kernel@vger.kernel.org, Arnd Bergmann <arnd@arndb.de>,
Christoph Hellwig <hch@lst.de>,
Russell King <linux@armlinux.org.uk>,
Linus Walleij <linus.walleij@linaro.org>,
Robin Murphy <robin.murphy@arm.com>,
Vinod Koul <vkoul@kernel.org>, Haibo Chen <haibo.chen@nxp.com>,
Ludovic Barre <ludovic.barre@st.com>,
linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [RESEND PATCH v2 1/2] driver core: platform: Initialize dma_parms for platform devices
Date: Wed, 22 Apr 2020 19:03:49 +0200 [thread overview]
Message-ID: <20200422170349.GA28781@lst.de> (raw)
In-Reply-To: <20200422100954.31211-1-ulf.hansson@linaro.org>
On Wed, Apr 22, 2020 at 12:09:54PM +0200, Ulf Hansson wrote:
> It's currently the platform driver's responsibility to initialize the
> pointer, dma_parms, for its corresponding struct device. The benefit with
> this approach allows us to avoid the initialization and to not waste memory
> for the struct device_dma_parameters, as this can be decided on a case by
> case basis.
>
> However, it has turned out that this approach is not very practical. Not
> only does it lead to open coding, but also to real errors. In principle
> callers of dma_set_max_seg_size() doesn't check the error code, but just
> assumes it succeeds.
>
> For these reasons, let's do the initialization from the common platform bus
> at the device registration point. This also follows the way the PCI devices
> are being managed, see pci_device_add().
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: <stable@vger.kernel.org>
> Tested-by: Haibo Chen <haibo.chen@nxp.com>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Arnd Bergmann <arnd@arndb.de>,
"Rafael J . Wysocki" <rafael@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Walleij <linus.walleij@linaro.org>,
Russell King <linux@armlinux.org.uk>,
Haibo Chen <haibo.chen@nxp.com>,
linux-kernel@vger.kernel.org, Vinod Koul <vkoul@kernel.org>,
linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
stable@vger.kernel.org, Robin Murphy <robin.murphy@arm.com>,
Christoph Hellwig <hch@lst.de>,
Ludovic Barre <ludovic.barre@st.com>
Subject: Re: [RESEND PATCH v2 1/2] driver core: platform: Initialize dma_parms for platform devices
Date: Wed, 22 Apr 2020 19:03:49 +0200 [thread overview]
Message-ID: <20200422170349.GA28781@lst.de> (raw)
In-Reply-To: <20200422100954.31211-1-ulf.hansson@linaro.org>
On Wed, Apr 22, 2020 at 12:09:54PM +0200, Ulf Hansson wrote:
> It's currently the platform driver's responsibility to initialize the
> pointer, dma_parms, for its corresponding struct device. The benefit with
> this approach allows us to avoid the initialization and to not waste memory
> for the struct device_dma_parameters, as this can be decided on a case by
> case basis.
>
> However, it has turned out that this approach is not very practical. Not
> only does it lead to open coding, but also to real errors. In principle
> callers of dma_set_max_seg_size() doesn't check the error code, but just
> assumes it succeeds.
>
> For these reasons, let's do the initialization from the common platform bus
> at the device registration point. This also follows the way the PCI devices
> are being managed, see pci_device_add().
>
> Suggested-by: Christoph Hellwig <hch@lst.de>
> Cc: <stable@vger.kernel.org>
> Tested-by: Haibo Chen <haibo.chen@nxp.com>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Looks good,
Reviewed-by: Christoph Hellwig <hch@lst.de>
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next prev parent reply other threads:[~2020-04-22 17:03 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 10:09 [RESEND PATCH v2 1/2] driver core: platform: Initialize dma_parms for platform devices Ulf Hansson
2020-04-22 10:09 ` Ulf Hansson
2020-04-22 17:03 ` Christoph Hellwig [this message]
2020-04-22 17:03 ` Christoph Hellwig
2020-04-23 13:25 ` Sasha Levin
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