From: Kirti Wankhede <kwankhede@nvidia.com>
To: Christoph Hellwig <hch@lst.de>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jason Gunthorpe <jgg@nvidia.com>,
"Alex Williamson" <alex.williamson@redhat.com>
Cc: Tony Krowiak <akrowiak@linux.ibm.com>,
Jason Herne <jjherne@linux.ibm.com>,
kvm@vger.kernel.org, Vasily Gorbik <gor@linux.ibm.com>,
Jonathan Corbet <corbet@lwn.net>, David Airlie <airlied@linux.ie>,
linux-s390@vger.kernel.org, Heiko Carstens <hca@linux.ibm.com>,
Cornelia Huck <cohuck@redhat.com>,
linux-doc@vger.kernel.org, dri-devel@lists.freedesktop.org,
Halil Pasic <pasic@linux.ibm.com>,
Christian Borntraeger <borntraeger@de.ibm.com>,
Rodrigo Vivi <rodrigo.vivi@intel.com>,
"Rafael J. Wysocki" <rafael@kernel.org>,
intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 02/10] driver core: Better distinguish probe errors in really_probe
Date: Tue, 15 Jun 2021 00:17:53 +0530 [thread overview]
Message-ID: <8002c963-ce48-ecf8-a209-58195818a160@nvidia.com> (raw)
In-Reply-To: <20210614150846.4111871-3-hch@lst.de>
On 6/14/2021 8:38 PM, Christoph Hellwig wrote:
> really_probe tries to special case errors from ->probe, but due to all
> other initialization added to the function over time now a lot of
> internal errors hit that code path as well. Untangle that by adding
> a new probe_err local variable and apply the special casing only to
> that.
>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
> drivers/base/dd.c | 72 +++++++++++++++++++++++++++--------------------
> 1 file changed, 41 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index 7477d3322b3a..999bc737a8f0 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -513,12 +513,42 @@ static ssize_t state_synced_show(struct device *dev,
> }
> static DEVICE_ATTR_RO(state_synced);
>
> +
> +static int call_driver_probe(struct device *dev, struct device_driver *drv)
> +{
> + int ret = 0;
> +
> + if (dev->bus->probe)
> + ret = dev->bus->probe(dev);
> + else if (drv->probe)
> + ret = drv->probe(dev);
> +
> + switch (ret) {
> + case -EPROBE_DEFER:
> + /* Driver requested deferred probing */
> + dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
> + break;
> + case -ENODEV:
> + case -ENXIO:
> + pr_debug("%s: probe of %s rejects match %d\n",
> + drv->name, dev_name(dev), ret);
> + break;
> + default:
> + /* driver matched but the probe failed */
> + pr_warn("%s: probe of %s failed with error %d\n",
> + drv->name, dev_name(dev), ret);
There should be case 0, that is, success case before default case as below:
+ case 0:
+ /* Driver returned success */
+ break;
Otherwise even in case of success, above warning would mislead that
probe has failed.
Thanks,
Kirti
> + break;
> + }
> +
> + return ret;
> +}
> +
> static int really_probe(struct device *dev, struct device_driver *drv)
> {
> - int ret = -EPROBE_DEFER;
> int local_trigger_count = atomic_read(&deferred_trigger_count);
> bool test_remove = IS_ENABLED(CONFIG_DEBUG_TEST_DRIVER_REMOVE) &&
> !drv->suppress_bind_attrs;
> + int ret = -EPROBE_DEFER, probe_ret = 0;
>
> if (defer_all_probes) {
> /*
> @@ -572,15 +602,15 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> goto probe_failed;
> }
>
> - if (dev->bus->probe) {
> - ret = dev->bus->probe(dev);
> - if (ret)
> - goto probe_failed;
> - } else if (drv->probe) {
> - ret = drv->probe(dev);
> - if (ret)
> - goto probe_failed;
> - }
> + probe_ret = call_driver_probe(dev, drv);
> + if (probe_ret) {
> + /*
> + * Ignore errors returned by ->probe so that the next driver can
> + * try its luck.
> + */
> + ret = 0;
> + goto probe_failed;
> + }
>
> if (device_add_groups(dev, drv->dev_groups)) {
> dev_err(dev, "device_add_groups() failed\n");
> @@ -650,28 +680,8 @@ static int really_probe(struct device *dev, struct device_driver *drv)
> dev->pm_domain->dismiss(dev);
> pm_runtime_reinit(dev);
> dev_pm_set_driver_flags(dev, 0);
> -
> - switch (ret) {
> - case -EPROBE_DEFER:
> - /* Driver requested deferred probing */
> - dev_dbg(dev, "Driver %s requests probe deferral\n", drv->name);
> + if (probe_ret == -EPROBE_DEFER)
> driver_deferred_probe_add_trigger(dev, local_trigger_count);
> - break;
> - case -ENODEV:
> - case -ENXIO:
> - pr_debug("%s: probe of %s rejects match %d\n",
> - drv->name, dev_name(dev), ret);
> - break;
> - default:
> - /* driver matched but the probe failed */
> - pr_warn("%s: probe of %s failed with error %d\n",
> - drv->name, dev_name(dev), ret);
> - }
> - /*
> - * Ignore errors returned by ->probe so that the next driver can try
> - * its luck.
> - */
> - ret = 0;
> done:
> atomic_dec(&probe_count);
> wake_up_all(&probe_waitqueue);
>
next prev parent reply other threads:[~2021-06-15 5:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210614150846.4111871-1-hch@lst.de>
[not found] ` <20210614150846.4111871-5-hch@lst.de>
2021-06-14 22:43 ` [PATCH 04/10] driver core: Don't return EPROBE_DEFER to userspace during sysfs bind Jason Gunthorpe
[not found] ` <20210614150846.4111871-2-hch@lst.de>
2021-06-15 5:16 ` [PATCH 01/10] driver core: Pull required checks into driver_probe_device() Greg Kroah-Hartman
2021-06-15 10:27 ` Cornelia Huck
[not found] ` <20210614150846.4111871-3-hch@lst.de>
2021-06-14 18:47 ` Kirti Wankhede [this message]
2021-06-15 5:17 ` [PATCH 02/10] driver core: Better distinguish probe errors in really_probe Greg Kroah-Hartman
2021-06-15 5:21 ` Allow mdev drivers to directly create the vfio_device (v2 / alternative) Greg Kroah-Hartman
[not found] ` <20210615055021.GB21080@lst.de>
2021-06-15 15:27 ` Jason Gunthorpe
[not found] ` <20210614150846.4111871-4-hch@lst.de>
2021-06-15 5:18 ` [PATCH 03/10] driver core: Flow the return code from ->probe() through to sysfs bind Greg Kroah-Hartman
2021-06-15 10:31 ` Cornelia Huck
[not found] ` <20210614150846.4111871-6-hch@lst.de>
2021-06-15 5:20 ` [PATCH 05/10] driver core: Export device_driver_attach() Greg Kroah-Hartman
2021-06-15 10:49 ` Cornelia Huck
[not found] ` <20210614150846.4111871-7-hch@lst.de>
2021-06-15 10:50 ` [PATCH 06/10] vfio/mdev: Remove CONFIG_VFIO_MDEV_DEVICE Cornelia Huck
[not found] ` <20210614150846.4111871-8-hch@lst.de>
2021-06-15 10:54 ` [PATCH 07/10] vfio/mdev: Allow the mdev_parent_ops to specify the device driver to bind Cornelia Huck
[not found] <20210615133519.754763-1-hch@lst.de>
[not found] ` <20210615133519.754763-3-hch@lst.de>
2021-06-15 13:53 ` [PATCH 02/10] driver core: Better distinguish probe errors in really_probe Cornelia Huck
2021-06-15 14:09 ` Greg Kroah-Hartman
2021-06-15 14:09 ` Greg Kroah-Hartman
2021-06-16 20:20 ` Kirti Wankhede
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