From: Bjorn Helgaas <helgaas@kernel.org>
To: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J. Wysocki" <rafael@kernel.org>,
Stuart Yoder <stuyoder@gmail.com>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Abel Vesa <abel.vesa@nxp.com>, Shawn Guo <shawnguo@kernel.org>,
Sascha Hauer <s.hauer@pengutronix.de>,
Fabio Estevam <festevam@gmail.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Mathieu Poirier <mathieu.poirier@linaro.org>,
Vineeth Vijayan <vneethv@linux.ibm.com>,
Peter Oberparleiter <oberpar@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Sven Schnelle <svens@linux.ibm.com>,
Andy Gross <agross@kernel.org>,
Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
Mark Brown <broonie@kernel.org>,
"Michael S. Tsirkin" <mst@redhat.com>,
Jason Wang <jasowang@redhat.com>,
linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org,
NXP Linux Team <linux-imx@nxp.com>,
linux-arm-kernel@lists.infradead.org,
linux-hyperv@vger.kernel.org, linux-pci@vger.kernel.org,
linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org,
linux-arm-msm@vger.kernel.org, alsa-devel@alsa-project.org,
linux-spi@vger.kernel.org,
virtualization@lists.linux-foundation.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Rasmus Villemoes <linux@rasmusvillemoes.dk>
Subject: Re: [PATCH v2 05/11] pci: use helper for safer setting of driver_override
Date: Thu, 24 Feb 2022 17:52:06 -0600 [thread overview]
Message-ID: <20220224235206.GA302751@bhelgaas> (raw)
In-Reply-To: <f7347531-8aa4-c011-d405-dea93e29779f@canonical.com>
On Thu, Feb 24, 2022 at 08:49:15AM +0100, Krzysztof Kozlowski wrote:
> On 23/02/2022 22:51, Bjorn Helgaas wrote:
> > In subject, to match drivers/pci/ convention, do something like:
> >
> > PCI: Use driver_set_override() instead of open-coding
> >
> > On Wed, Feb 23, 2022 at 08:13:04PM +0100, Krzysztof Kozlowski wrote:
> >> Use a helper for seting driver_override to reduce amount of duplicated
> >> code.
> >> @@ -567,31 +567,15 @@ static ssize_t driver_override_store(struct device *dev,
> >> const char *buf, size_t count)
> >> {
> >> struct pci_dev *pdev = to_pci_dev(dev);
> >> - char *driver_override, *old, *cp;
> >> + int ret;
> >>
> >> /* We need to keep extra room for a newline */
> >> if (count >= (PAGE_SIZE - 1))
> >> return -EINVAL;
> >
> > This check makes no sense in the new function. Michael alluded to
> > this as well.
>
> I am not sure if I got your comment properly. You mean here:
> 1. Move this check to driver_set_override()?
> 2. Remove the check entirely?
I was mistaken about the purpose of the comment and the check. I
thought it had to do with *this* function, and this function doesn't
add a newline, and there's no obvious connection with PAGE_SIZE.
But looking closer, I think the "extra room for a newline" is really
to make sure that *driver_override_show()* can add a newline and have
it still fit within the PAGE_SIZE sysfs limit.
Most driver_override_*() functions have the same comment, so maybe
this was obvious to everybody except me :) I do see that spi.c adds
"when displaying value" at the end, which helps a lot.
Sorry for the wild goose chase.
> >> - driver_override = kstrndup(buf, count, GFP_KERNEL);
> >> - if (!driver_override)
> >> - return -ENOMEM;
> >> -
> >> - cp = strchr(driver_override, '\n');
> >> - if (cp)
> >> - *cp = '\0';
> >> -
> >> - device_lock(dev);
> >> - old = pdev->driver_override;
> >> - if (strlen(driver_override)) {
> >> - pdev->driver_override = driver_override;
> >> - } else {
> >> - kfree(driver_override);
> >> - pdev->driver_override = NULL;
> >> - }
> >> - device_unlock(dev);
> >> -
> >> - kfree(old);
> >> + ret = driver_set_override(dev, &pdev->driver_override, buf);
> >> + if (ret)
> >> + return ret;
> >>
> >> return count;
> >> }
> >> --
> >> 2.32.0
> >>
> >>
> >> _______________________________________________
> >> linux-arm-kernel mailing list
> >> linux-arm-kernel@lists.infradead.org
> >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
> Best regards,
> Krzysztof
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2022-02-24 23:52 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-23 19:12 [PATCH v2 00/11] Fix broken usage of driver_override (and kfree of static memory) Krzysztof Kozlowski
2022-02-23 19:13 ` [PATCH v2 01/11] driver: platform: add and use helper for safer setting of driver_override Krzysztof Kozlowski
2022-02-23 21:33 ` Michael S. Tsirkin
2022-02-24 7:46 ` Krzysztof Kozlowski
2022-02-23 21:53 ` Bjorn Helgaas
2022-02-24 7:47 ` Krzysztof Kozlowski
2022-02-24 8:43 ` Krzysztof Kozlowski
2022-02-23 19:13 ` [PATCH v2 02/11] amba: " Krzysztof Kozlowski
2022-02-23 19:13 ` [PATCH v2 03/11] fsl-mc: " Krzysztof Kozlowski
2022-02-23 19:13 ` [PATCH v2 04/11] hv: vmbus: " Krzysztof Kozlowski
2022-02-23 19:13 ` [PATCH v2 05/11] pci: " Krzysztof Kozlowski
2022-02-23 21:51 ` Bjorn Helgaas
2022-02-24 7:49 ` Krzysztof Kozlowski
2022-02-24 23:52 ` Bjorn Helgaas [this message]
2022-02-25 9:36 ` Krzysztof Kozlowski
2022-02-25 17:13 ` Bjorn Helgaas
2022-02-23 19:13 ` [PATCH v2 06/11] s390: cio: " Krzysztof Kozlowski
2022-02-23 19:14 ` [PATCH v2 07/11] spi: " Krzysztof Kozlowski
2022-02-23 20:04 ` Mark Brown
2022-02-23 20:13 ` Krzysztof Kozlowski
2022-02-23 19:14 ` [PATCH v2 08/11] vdpa: " Krzysztof Kozlowski
2022-02-23 19:14 ` [PATCH v2 09/11] clk: imx: scu: fix kfree() of static memory on setting driver_override Krzysztof Kozlowski
2022-02-23 19:19 ` Krzysztof Kozlowski
2022-02-23 19:14 ` [PATCH v2 10/11] slimbus: qcom-ngd: " Krzysztof Kozlowski
2022-02-23 19:14 ` [PATCH v2 11/11] rpmsg: " Krzysztof Kozlowski
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